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Russia’s Proton-M rocket made its first flight in six months Thursday, on track to deploy a Blagovest military communications satellite. Launch occurred from the Baikonur Cosmodrome in Kazakhstan at 04:12 local time (22:12 UTC on Wednesday), ahead of over nine hours of flight to deployment of its passenger.

Thursday’s launch is carrying the Blagovest No.12L satellite, the second spacecraft in a new series of communications satellites for Russia’s Ministry of Defence. After launch the satellite is likely to be renamed Kosmos 2526 under the designation scheme that Russia uses for its military spacecraft. Few details about the spacecraft have been made public.

Blagovest – meaning Good News – is a project that has been funded by the Russian military. Each satellite carries a payload of Ka and Q-band transponders. Although the satellites are being launched for the Ministry of Defence, they are reportedly equipped for telephony, broadcasting and internet services – which will support a dual-use mission with commercial service as well as linking Russia’s military bases.

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The Blagovest spacecraft are built by ISS Reshetnev – the successor to the Soviet-era NPO PM design bureau that was headed by Mikhail Reshetnev. Blagovest is based around the Ekspress 2000 bus that has previously been used for the civilian Ekspress-AM5 and AM6 and Yamal 401 satellites. Once in orbit the satellite will deploy a pair of solar arrays to generate power. It is expected to remain in service for fifteen years.

The Blagovest constellation is expected to consist of at least four satellites in geostationary orbit. It will include spacecraft at longitudes of 45 and 128 degrees East – Kosmos 2520 operates at 45 degrees East.

Thursday’s launch of Blagovest No.12L follows the successful deployment of Blagovest No.11L, the first satellite in the series, last August. Now known as Kosmos 2520, Blagovest No.11L was deployed by a Proton-M rocket with a Briz-M upper stage flying out of Site 81/24 at the Baikonur Cosmodrome. Blagovest No.12L is riding to orbit aboard the same type of rocket, flying from the same launch pad.

Proton-M on a previous launch – via Roscosmos

Proton has served as a workhorse of the Russian – and previously Soviet – space programmes for many years. First developed in the 1960s, Proton was derived from Vladimir Chelomei’s Universal Rocket 500 (UR-500), a massive intercontinental ballistic missile designed to carry the Soviet Union’s heaviest nuclear warheads like the Tsar Bomba. While the two-stage UR-500 never flew as a missile, four were launched between 1965 and 1966 with N-4 scientific satellites – named Proton once in orbit. The rocket was named after these payloads.

With a modified second stage and a new third stage, the UR-500 became the Proton-K. This rocket allowed the USSR to deploy most of its heaviest satellites and – with the addition of the Blok-D family of upper stages – gave the country access to geostationary orbit and the ability to launch new and heavier missions to the Moon, Venus and Mars.

Proton-K was also to have launched the Soyuz 7K-L1 spacecraft – also known as Zond – on manned flybys of the Moon. The rocket’s maiden flight in March 1967 – using a four-stage vehicle with a Blok-D upper stage – carried an unmanned prototype. During its early years, Proton-K was extremely unreliable – recording eight launch failures from ten flights in 1969 – and this, combined with the resulting delays, led to the manned Lunar flybys being abandoned. The rocket’s reliability improved after a heavily-instrumented suborbital test launch in 1970 and the following year a three-stage Proton-K deployed Salyut 1, the first space station.

Proton-K rockets launched all of the space stations in the Salyut programme – both the civilian DOS and military Almaz vehicles. The Proton-K also deployed all modules of the later Mir space station except the Stykovochnyy Otsek docking module that was delivered by Space Shuttle Atlantis, and the Zarya and Zvezda modules of the International Space Station.

The Beginning - Russian Proton Rocket Launches Zarya ISS Core 1998-11-20 - YouTube

In the 1990s, Russia began offering commercial Proton launches through International Launch Services (ILS), a company which also marketed the American Atlas II rocket. ILS continues to fly commercial missions aboard Proton, however at a reduced rate in recent years as concerns have resurfaced about the vehicle’s reliability.

The Proton-M is a modernized version of the Proton-K which first flew in April 2001. Also incorporating upgraded engines, Proton-M increased the rocket’s payload capacity. It is typically paired with a Briz-M upper stage, which had been tested on two Proton-K launches prior to the Proton-M’s debut, and two more in 2003.

Briz-M is a storable-propellant upper stage with a detachable propellant tank, optimized for the long-duration missions required to reach geostationary orbit from the Baikonur Cosmodrome. Proton-M has also flown several missions with the older Blok DM-2 upper stage – deploying Glonass navigation satellites – and its successor, Blok DM-03. Proton-K was phased out for commercial launches by 2003 and made its final flight in 2012.

Between 2006 and 2015, most years saw a Proton launch failure – with none in 2009 but two in 2012 and 2014. Proton suffered another near-miss during June 2016’s launch of Intelsat 31 – when one of four second-stage engines failed nine seconds before the end of its planned burn. Although Intelsat 31 was deployed into its planned orbit – with the Briz-M fourth stage burning for longer than planned to make up the underperformance – the episode dented confidence in Proton. Combined with delays resulting from quality control issues with its engines, the rocket would remain grounded for almost a year – the longest time between launches in its history.

Proton-M returned to flight last June – two days before the anniversary of its previous launch – with the first of four missions launched last year. Protons also deployed the previous Blagovest satellite in August and two commercial satellites via separate launches in September.

Proton rockets launch exclusively from the Baikonur Cosmodrome in Kazakhstan. Four launch pads were built – pads 23 and 24 at Site 81 and pads 39 and 40 at Site 200. Of these, only pads 24 and 39 remain operational – Pad 40 has not been used since 1991, while the last launch from Pad 23 took place in 2005.

Regardless of which pad they are launching from, Proton rockets are assembled horizontally with payload integration and Briz-M fuelling taking place before the rocket is rolled out and erected at the pad. Ahead of Thursday’s launch Proton-M was transported to Pad 24 on Sunday morning.

ILS Proton-M launch

Proton uses storable hypergolic propellants – unsymmetrical dimethylhydrazine (UDMH) oxidized by dinitrogen tetroxide – which are toxic and environmentally hazardous. This has resulted in pressure from Kazakhstan on Russia to withdraw the rocket from use.

Russia’s new Angara rocket will eventually replace Proton; however, Proton launches are expected to continue for the foreseeable future. A new Proton Medium rocket – consisting of the rocket’s first two stages and a Briz-M – has recently been announced to provide cheaper launches for lighter payloads and incremental upgrades have been made to the Proton-M since its introduction.

Thursday’s launch was the 417th flight of Proton, and the 103rd to use a Proton-M.

To allow Proton to be transported by train, Chelomei designed its first stage with six propellant tanks clustered radially around a central oxidizer tank – with final integration taking place at Baikonur. The stage’s six RD-276 engines are located underneath the fuel tanks.

Two and a half seconds before its planned liftoff, Proton began the ignition sequence for its first stage engines, with ignition itself taking place three-quarters of a second later. The engines reached full thrust about nine-tenths of a second before launch.

After lifting off, Proton passed through max-Q – the area of maximum dynamic pressure – about a minute into the mission. Two minutes into flight, the first stage separation event took place. Proton’s second stage ignited before the first stage is jettisoned, with the exhaust gasses venting through the lattice interstage between the two.

Proton’s second stage is powered by four engines: three RD-0210s and an RD-0211. The two types of engine are essentially the same, with the RD-0211 including an additional gas generator to maintain pressure in the propellant tanks. The second stage burned for three minutes and 27 seconds.

At the end of second-stage flight, Proton’s third stage ignited. This is powered by an RD-0212 – comprising a main engine and a vernier engine for attitude control. The third stage burned for four minutes and 15 seconds. About twenty seconds into its burn, Proton’s payload fairing separated from the nose of the vehicle.

About nine minutes and 42 seconds after liftoff, Proton’s third stage completed its role in Thursday’s launch and handed over to the Briz-M. Within a minute and a half to two minutes of separating from the Proton, Briz-M began its first burn to reach an initial parking orbit. This burn lasted a little over four minutes. Briz-M will make a series of four burns to inject its payload directly into geostationary orbit. Spacecraft separation will not take place until around nine hours after launch.

The first Proton launch since last September, Thursday’s launch was the first of only three or four expected to take place in 2018. The only other Proton launches confirmed to be on schedule for 2018 are a commercial mission with Eutelsat 5 West B and Orbital ATK’s first Mission Extension Vehicle (MEV-1) – which is slated for no earlier than the third quarter of the year – and the deployment of an Elektro-L weather satellite for Roskosmos in October.

An additional military launch could occur later in the year. Planned launches of the Yamal 601 communications satellite and the Nauka module of the International Space Station were recently delayed until 2019.

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Russia’s Proton-M rocket will make its first flight in six months Thursday, deploying a Blagovest military communications satellite. Launch is expected from the Baikonur Cosmodrome in Kazakhstan at 04:12 local time (22:12 UTC on Wednesday).

Thursday’s launch will carry the Blagovest No.12L satellite, the second spacecraft in a new series of communications satellites for Russia’s Ministry of Defence. After launch the satellite is likely to be renamed Kosmos 2526 under the designation scheme that Russia uses for its military spacecraft. Few details about the spacecraft have been made public.

Blagovest – meaning Good News – is a project that has been funded by the Russian military. Each satellite carries a payload of Ka and Q-band transponders. Although the satellites are being launched for the Ministry of Defence, they are reportedly equipped for telephony, broadcasting and internet services – which will support a dual-use mission with commercial service as well as linking Russia’s military bases.

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The Blagovest spacecraft are built by ISS Reshetnev – the successor to the Soviet-era NPO PM design bureau that was headed by Mikhail Reshetnev. Blagovest is based around the Ekspress 2000 bus that has previously been used for the civilian Ekspress-AM5 and AM6 and Yamal 401 satellites. Once in orbit the satellite will deploy a pair of solar arrays to generate power. It is expected to remain in service for fifteen years.

The Blagovest constellation is expected to consist of at least four satellites in geostationary orbit. It will include spacecraft at longitudes of 45 and 128 degrees East – Kosmos 2520 operates at 45 degrees East.

Thursday’s launch of Blagovest No.12L follows the successful deployment of Blagovest No.11L, the first satellite in the series, last August. Now known as Kosmos 2520, Blagovest No.11L was deployed by a Proton-M rocket with a Briz-M upper stage flying out of Site 81/24 at the Baikonur Cosmodrome. Blagovest No.12L will ride to orbit aboard the same type of rocket, flying from the same launch pad.

Proton-M on a previous launch – via Roscosmos

Proton has served as a workhorse of the Russian – and previously Soviet – space programmes for many years. First developed in the 1960s, Proton was derived from Vladimir Chelomei’s Universal Rocket 500 (UR-500), a massive intercontinental ballistic missile designed to carry the Soviet Union’s heaviest nuclear warheads like the Tsar Bomba. While the two-stage UR-500 never flew as a missile, four were launched between 1965 and 1966 with N-4 scientific satellites – named Proton once in orbit. The rocket was named after these payloads.

With a modified second stage and a new third stage, the UR-500 became the Proton-K. This rocket allowed the USSR to deploy most of its heaviest satellites and – with the addition of the Blok-D family of upper stages – gave the country access to geostationary orbit and the ability to launch new and heavier missions to the Moon, Venus and Mars.

Proton-K was also to have launched the Soyuz 7K-L1 spacecraft – also known as Zond – on manned flybys of the Moon. The rocket’s maiden flight in March 1967 – using a four-stage vehicle with a Blok-D upper stage – carried an unmanned prototype. During its early years, Proton-K was extremely unreliable – recording eight launch failures from ten flights in 1969 – and this, combined with the resulting delays, led to the manned Lunar flybys being abandoned. The rocket’s reliability improved after a heavily-instrumented suborbital test launch in 1970 and the following year a three-stage Proton-K deployed Salyut 1, the first space station.

Proton-K rockets launched all of the space stations in the Salyut programme – both the civilian DOS and military Almaz vehicles. The Proton-K also deployed all modules of the later Mir space station except the Stykovochnyy Otsek docking module that was delivered by Space Shuttle Atlantis, and the Zarya and Zvezda modules of the International Space Station.

The Beginning - Russian Proton Rocket Launches Zarya ISS Core 1998-11-20 - YouTube

In the 1990s, Russia began offering commercial Proton launches through International Launch Services (ILS), a company which also marketed the American Atlas II rocket. ILS continues to fly commercial missions aboard Proton, however at a reduced rate in recent years as concerns have resurfaced about the vehicle’s reliability.

The Proton-M is a modernized version of the Proton-K which first flew in April 2001. Also incorporating upgraded engines, Proton-M increased the rocket’s payload capacity. It is typically paired with a Briz-M upper stage, which had been tested on two Proton-K launches prior to the Proton-M’s debut, and two more in 2003.

Briz-M is a storable-propellant upper stage with a detachable propellant tank, optimized for the long-duration missions required to reach geostationary orbit from the Baikonur Cosmodrome. Proton-M has also flown several missions with the older Blok DM-2 upper stage – deploying Glonass navigation satellites – and its successor, Blok DM-03. Proton-K was phased out for commercial launches by 2003 and made its final flight in 2012.

Between 2006 and 2015, most years saw a Proton launch failure – with none in 2009 but two in 2012 and 2014. Proton suffered another near-miss during June 2016’s launch of Intelsat 31 – when one of four second-stage engines failed nine seconds before the end of its planned burn. Although Intelsat 31 was deployed into its planned orbit – with the Briz-M fourth stage burning for longer than planned to make up the underperformance – the episode dented confidence in Proton. Combined with delays resulting from quality control issues with its engines, the rocket would remain grounded for almost a year – the longest time between launches in its history.

Proton-M returned to flight last June – two days before the anniversary of its previous launch – with the first of four missions launched last year. Protons also deployed the previous Blagovest satellite in August and two commercial satellites via separate launches in September.

Proton rockets launch exclusively from the Baikonur Cosmodrome in Kazakhstan. Four launch pads were built – pads 23 and 24 at Site 81 and pads 39 and 40 at Site 200. Of these, only pads 24 and 39 remain operational – Pad 40 has not been used since 1991, while the last launch from Pad 23 took place in 2005.

Regardless of which pad they are launching from, Proton rockets are assembled horizontally with payload integration and Briz-M fuelling taking place before the rocket is rolled out and erected at the pad. Ahead of Thursday’s launch Proton-M was transported to Pad 24 on Sunday morning.

ILS Proton-M launch

Proton uses storable hypergolic propellants – unsymmetrical dimethylhydrazine (UDMH) oxidized by dinitrogen tetroxide – which are toxic and environmentally hazardous. This has resulted in pressure from Kazakhstan on Russia to withdraw the rocket from use.

Russia’s new Angara rocket will eventually replace Proton; however, Proton launches are expected to continue for the foreseeable future. A new Proton Medium rocket – consisting of the rocket’s first two stages and a Briz-M – has recently been announced to provide cheaper launches for lighter payloads and incremental upgrades have been made to the Proton-M since its introduction.

Thursday’s launch will be the 417th flight of Proton, and the 103rd to use a Proton-M.

To allow Proton to be transported by train, Chelomei designed its first stage with six propellant tanks clustered radially around a central oxidizer tank – with final integration taking place at Baikonur. The stage’s six RD-276 engines are located underneath the fuel tanks.

Two and a half seconds before its planned liftoff, Proton will begin the ignition sequence for its first stage engines, with ignition itself taking place three-quarters of a second later. The engines will reach full thrust about nine-tenths of a second before launch.

After lifting off, Proton will pass through max-Q – the area of maximum dynamic pressure – about a minute into the mission. Two minutes into flight, the first stage separation event will take place. Proton’s second stage ignites before the first stage is jettisoned, with the exhaust gasses venting through the lattice interstage between the two.

Proton’s second stage is powered by four engines: three RD-0210s and an RD-0211. The two types of engine are essentially the same, with the RD-0211 including an additional gas generator to maintain pressure in the propellant tanks. The second stage will burn for three minutes and 27 seconds.

At the end of second-stage flight, Proton’s third stage will ignite. This is powered by an RD-0212 – comprising a main engine and a vernier engine for attitude control. The third stage will burn for four minutes and 15 seconds. About twenty seconds into its burn, Proton’s payload fairing will separate from the nose of the vehicle.

About nine minutes and 42 seconds after liftoff, Proton’s third stage will complete its role in Thursday’s launch and hand over to the Briz-M. Within a minute and a half to two minutes of separating from the Proton, Briz-M will begin its first burn to reach an initial parking orbit. This burn will last a little over four minutes. Briz-M will make a series of four burns to inject its payload directly into geostationary orbit. Spacecraft separation will not take place until around nine hours after launch.

The first Proton launch since last September, Thursday’s launch is the first of only three or four expected to take place in 2018. The only other Proton launches confirmed to be on schedule for 2018 are a commercial mission with Eutelsat 5 West B and Orbital ATK’s first Mission Extension Vehicle (MEV-1) – which is slated for no earlier than the third quarter of the year – and the deployment of an Elektro-L weather satellite for Roskosmos in October.

An additional military launch could occur later in the year. Planned launches of the Yamal 601 communications satellite and the Nauka module of the International Space Station were recently delayed until 2019.

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NASA Exploration Ground Systems (EGS) and prime test and operations contractor Jacobs are busy practicing how to put Solid Rocket Boosters (SRB) together in High Bay 4 of the Vehicle Assembly Building (VAB) at the Kennedy Space Center (KSC) in Florida. Working with inert motor segments and booster hardware, the EGS and Jacobs team are running through all the procedures they will use to process the SRB flight hardware for the first Space Launch System (SLS) launch, Exploration Mission-1 (EM-1).

The practice and training events cover the different procedural checklists the workforce will step through and the different KSC facilities where the Orbital ATK boosters will be processed once they arrive from Utah.

Jacobs provides operational support for all EGS launch processing activities and is prime for their test and operations support contract (TOSC). Along with EGS, their personnel are getting hands-on training by practicing with the ground support equipment and flight-like hardware in High Bay 4.

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“Fundamentally, in order to get our workforce in a position where they’re trained and ready to support we try to establish things like these. We’ll have either a pathfinder event or we’ll have ourselves a training event,” David Diaz, NASA Operations Manager for Integrated Flow, said in an interview with NASASpaceflight.com.

“We try to use as much flight hardware — old flight hardware — as possible. So what did here was we were able to acquire, working with our different flight elements, we were able to acquire these particular parts from the booster [office].”

“This is where we train our technicians for hands-on touch labor, engineers are getting trained up on move director certification, so we’re getting a lot of our young Jacobs engineers, technicians, and crane crew all trained,” Kerry Chreist, Jacobs Flow Manager for the Rotation, Processing and Surge Facility (RPSF), added.

“This is a training event that trains not only the technicians [and] engineering [personnel], it also trains our quality [control], [and] it also trains our safety people [for] what we’ll be experiencing during the EM-1 processing.”

EGS Jacobs TOSC technicians working at the tang end of a bare metal booster cylinder. Credit: NASA/Glenn E. Benson

“This is a win-win training situation [for] brushing off the processes and procedures that we’re going to be doing during the EM-1 processing,” Chreist continued.

We’re conducting the same processes in training that we’ll be doing for EM-1. Some of that is the tang inspection, O-ring [inspection]. [After] joint mate we’ll be doing the test procedures for joint leak tests to make sure that we have a tight joint and that we’re not leaking past the O-rings. So we’re doing everything possible to simulate everything that we’ll do when we actually process the flight hardware.”

The team is working with two booster segments and two empty, bare metal cylinders that would make up the outside of segment. “Basically what creates that big segment is two individual cylinders, we have those. We can pretty much use one of the cylinders to mate it to the aft assembly, which is up in our buildup stands in the High Bay 4,” Diaz explained. “And then other direction, we’ll go ahead and get the center segment we’ll mate that to the other cylinder, it kind of gives us both ends.”

Looking up at the inert aft assembly in the build up stand in High Bay 4. Credit: NASA/Kim Shiflett

An outfitted aft assembly, with an inert aft segment, aft skirt, and nozzle extension, is configured in one stand in the high bay and an inert center segment is also there for the practice stacking activities. “This is actual one-time flight hardware, so it gives us a very flight-like environment for our TOSC workforce to go do their training and certification programs,” Diaz added.

The material in the inert segments is cast so that they have the same weight and balance characteristics as flight segments.

Ground Support Equipment: cranes, beams, stands and stations:

Outnumbering the booster rocket hardware in High Bay 4 is all the ground support equipment needed to inspect and prepare the segments to be attached to each other, and finally to move them into High Bay 3 for mating. “We basically have four stations set up there in the high bay that we’ll be using in the booster stacking when we do EM-1,” Chreist noted.

The segments are brought into the VAB sitting on a pallet. “This is how we transport it back and forth from the RPSF to the VAB when we’re ready to start processing of the hardware,” he explained. The pallet is picked up by a transporter in the RPSF and then lowered down after arrival in the high bay.

From left to right: bare metal cylinder, aft assembly in build up stand, one resting ‘384’ beam, another ‘384’ beam attached to the VAB 325-ton crane and the other empty cylinder, inert center segment sitting on a transportation pallet in High Bay 4. Credit: NASA/Kim Shiflett

Cranes lift and move large, massive hardware around the VAB. For booster hardware, a crane first attaches to a lifting beam that is then attached to a segment. “It’s called the 384 beam,” Chreist said. “That’s the beam that we actually hook up to the segments and move them around, both in the RPSF and we’ll be doing that in the VAB.”

The segments are connected at a tang/clevis field joint, with bottom, tang end of one cylinder lowered down onto the top clevis end of the other; pins around both circumferences then fasten them together.

The 384 four-point lifting beam has a similar tang interface to allow it to attach to the top, clevis end of a segment for lifting. There are two tangs at each of the lifting beam’s four quadrants where they are pinned to the segment.

Close-up of how the four-point ‘384’ lifting beam attaches to the top of a booster segment cylinder. Credit: NASA/Glenn E. Benson

After the beam is attached to the segment, it is lifted over to another workstation. “That’s station 3,” Chreist noted. “We lower the segment and put it down on there and what we can do is we can prep the tang, we do the inspection for the O-rings, we re-grease it and we prep it prior to doing mating operations.”

“We cannot prep it when it’s on the pallet, we have to pick it up and then we prep the joint,” he continued. “We pick it up and we’ll rotate it and then we get the joint completely prepped before we go, we call it going up and over, and get it ready for mate practice.”

At the beginning of the year, the team was using one of the bare metal cylinders to practice mating the field joint between the cylinder and the aft assembly. More recently, workers have been practicing with the other cylinder and the inert center segment at station 2. “Station 2 is where we have the ‘400’ stand, the work-stand, and we have a [bare metal] cylinder segment sitting there on that,” Chreist said.

The workstand with the empty cylinder is located on the floor in High Bay 4. Workers are practicing attaching the crane and a 384 lifting beam to the top of center segment, inspecting and preparing the bottom for mating, and then lifting the segment on top of the empty cylinder on the 400 stand and mating them together.

After the booster segments are physically fastened together with hundreds of pins around their circumference, the field joint is closed out with cork and room temperature vulcanizer (RTV) to protect the joint from the outside environment before and during launch. Those have to be applied to the joint in a controlled environment and so before each segment is lifted into High Bay 3 for stacking, it has essentially a rolled up, clear plastic tent — an environmental enclosure — attached around the bottom.

“It’s basically a shielding of the environment,” Chreist explained.  “The humidity is controlled and the temperature is controlled. Basically what we do is we set up the enclosure prior to the joint mate, then we go ‘up and over’ [and] we do the mating process,” he continued.

The rolled up plastic environmental enclosure, as seen around the bottom end of a Shuttle booster segment being lifted in the VAB Transfer Aisle in 2004. Credit: NASA

“Once the segment is lowered into place, the enclosure is unrolled down around work platforms surrounding the field joint area and sealed up for air conditioning.  Then the rest of the enclosure is sealed up and what we do is we environmentally control this — for humidity, temperature, and everything for joint closeout and also for the bonding of the cork and the RTV.”

The plastic itself is not critical for practicing the process of mating the hardware, but Diaz noted the team will practice some of the pre-lift work with it. “We will have set up — simulated [the] set up of — the actual enclosure structure and wrung out the plastic,” he said. “We just won’t be up on the platform, so we would have V&V’d it that way.”

As seen following set up for Shuttle booster segment mating in 2004, the plastic enclosure is draped over a work platform where the two segment are brought together. Environmental controls can be applied to create a clean room area. Credit: NASA

In addition stacking activities, the team is also practicing the reverse, destacking procedures. For the recent practice with the center segment, the practice is valuable, but the destacking is mandatory. “After we mate the joint over in High Bay 4, [where] we’re doing the segment mate training, we have to do a destack because cannot leave it on the 400 stand, we cannot leave that segment sitting on top of that cylinder,” Chreist explained.

“So what we do is we leave the crane attached, we do the joint mate, we do a leak check, and then at the end of the day what we do is…a de-pinning operation and take that segment back to the pallet. At night it is sat back on the pallet and the crane with the 384 beam is disconnected and everything is going to a resting place until we pick up [practice] at another time.”

RPSF practice:

The stacking practice in High Bay 4 is one in a series of training and certification events that EGS and Jacobs are performing ahead of EM-1 booster processing. The RPSF is one of the first stops for the booster’s motor segments when they arrive from Orbital ATK’s manufacturing and production facilities in Promontory, Utah.

Prior to the current activities, build up of the aft assembly provided the workforce with an opportunity to go through the procedures they’ll perform on the two flight assemblies next year in the RPSF.

“Back in about 2016, we went off and did what’s called an RPSF pathfinder effort,” Diaz explained. “Basically we took the whole processing flow for the RPSF, very similar to what they’re doing with the stacking operations in the VAB, and wrung out all our processes, all our paper, all our plans, what we planned to do. And that point is where we ended up using this aft segment in a build up.”

“We put that in a build up stand and we basically built that up there, wrung through our processes,” he continued. “We also were able to V&V (verify and validate) the [platform] development efforts — they did some modifications to the platforms due to the wider nozzle. So we got that all done and [that] was a mock up that TOSC went ahead and fabricated based on the drawings.”

Completed inert aft assembly in the RPSF, December, 2016. Credit: NASA

“Once we had the segments over at the RPSF we tested out our SRM transporter, we did…our route verification for EM-1 of how we were going to bring it around to High Bay 4,” Chreist added. “So we did a lot of training at the RPSF, not only the reactivation of the facility and certifying that the facility was ready to support the program.

“We conducted all the training for the Jacobs employees on both engineering, safety, quality, to hands-on flight technicians, so it was a win-win for the program there, so we’ve checked the box on there that the program is ready to support at the RPSF when the flight hardware is ready to arrive.”

Stacking flight hardware:

The iconic VAB is primarily divided into four high bays or cells, two “integration” cells facing east towards the launch pads and the Atlantic Ocean, and two facing to the west.

The cells are divided by a transfer aisle which extends to the south into a Low Bay. Exploration Mission vehicles with SLS launchers and Orion spacecraft will be stacked on a Mobile Launcher in the north east cell, High Bay 3.

Placard as seen entering the VAB in 2012. Cranes will lift the fully prepped booster segments up sixteen stories where they can cross from left to right in the diagram, going from High Bay 4 to High Bay 3. Credit: Philip Sloss for NSF/L2.

Space Shuttle vehicles — SRBs, External Tanks, and Orbiters — were stacked in the east side cells, High Bays 1 and 3. Generally all of the hardware was received or staged in the transfer aisle to be lifted into the high bays; booster segments would be transported from the nearby RPSF into the transfer aisle, where much of the same stacking prep work being practiced now by EGS and Jacobs would be performed.

For SLS, the final preparation work in the VAB before stacking segments will be done as is being rehearsed now, in High Bay 4. “It’s a very, very similar process that we did in Shuttle,” Chreist explained. “This time we’re starting it in High Bay 4.”

“We’re going to come over from the RPSF and we’re pretty much going to start with the aft assembly coming in,” Chreist said. “It comes into High Bay 4 and then at that point our folks that have got all the training there, our stations all set up there, they’re already familiar with the area, [so] it makes sense to come on in, we’ve got our transportation [route] set up.”

A crane lifting a Shuttle booster segment in the VAB in 2004 after clearing the 16th floor crossover into High Bay 3. Credit: NASA

“We’ll hook up the 384 lifting beam, we’ll pick up the aft segment assembly and of course there’s preps and so forth associated with all of that. We’ll take it up and over the crossover into High Bay 3, we’ll perform our clears, get that all set up and put that aft assembly onto the ML posts.”

“And then we move on to the different segments we have,” he continued. “They’re very, very similar. We’ll bring it up over onto the slap stand, we’ll do all our preps, and we’ll take it up and over. We’ll take it up and over the crossover into High Bay 3, we’ll perform our clears, get that all set up and put that aft assembly onto the ML posts.”

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NASA and SpaceX are in final preparations for the launch of the Transiting Exoplanet Survey Satellite, or TESS.  The planet-hunting observatory will be launched by a brand new Block 4 Falcon 9 rocket from SLC-40 into an orbital resonance with the moon that will allow it to perform a near all-sky survey to find and categorize the number and types of exoplanets within 300 light years of Earth.  Liftoff is targeted for a 30 second window that opens at 18:32:07 EDT (22:32:07 UTC) on Monday, 16 April.

TESS background/overview:

The original idea for TESS goes back to 2005 when Dr. George Ricker was the Principle Investigator High Energy Transient Explorer (HETE) – the first satellite mission dedicated to the study of gamma-ray bursts.  Slowly, the idea evolved in 2008 and 2009, with Dr. Ricker, now TESS’s Principal Investigator at MIT (Massachusetts Institute of Technology), saying “We wanted to initially try to do this as a privately funded system, and MIT was very helpful for us.  We had support from Google for some of the studies that were originally going to be done.”

That led to a collaboration with NASA Ames to create a proposal for a small-class explorer exoplanet mission that was ultimately not selected for flight.  That then led to a partnership with Orbital ATK and the Goddard Space Flight Center in Greenbelt, Maryland, for a revised mission proposal over 2011 and 2012.

TESS was officially selected for inclusion in NASA’s Medium Explorer mission program on 5 April 2013, and with just over five years of design and build operations, now stands ready to launch.  “It’s been a long time coming. It’s been 13 years, but for the last five years, basically, pretty much [everything with the mission has been] the same,” said Dr. Ricker.

TESS undergoes final pre-launch processing at the Kennedy Space Center. (Credit: Chris Gebhardt for NSF/L2)

While TESS is generally perceived as a follow-on to NASA’s Kepler planet hunting satellite, it will perform a very different kind of mission.  Where Kepler was a prolonged, deep, and narrow field observatory that looked continuously at specific stars in one quarter of 1% of the sky at an optimal range of 2,000 to 3,000 light years distance, TESS will perform a wide- and shallow-field survey covering 85% of the sky with an optimal distance stretching to 300 light years.

TESS will accomplish its observations by using the sole science instrument onboard: a package of four wide-field-of-view CCD cameras with a low-noise, low-power 16.8 megapixel CCD detector.  Each camera as a 24° x 24° field of view, a 100 mm (4 in) pupil diameter, a lens assembly with seven optical elements, and a bandpass range of 600 to 1,000 nm.

When functioning together – as designed – the four cameras have a 24° x 96° field of view.

The overall spacecraft is built on a LEOStar-2 satellite bus by Orbital ATK.  The spacecraft bus is capable of three-axis stabilization via four hydrazine thrusters as well as four reaction wheels.  This provides TESS’s cameras with greater than three-arc-second fine pointing control – necessary for the sensitive light observations TESS will perform once in its science orbit.

Transiting Exoplanet Survey Satellite (TESS) - YouTube

The data collected during TESS’s observational campaigns – as well as general spacecraft communications – will route through a Ka-band antenna with a 100 Mbit/s downlink capability.  The entire craft is powered by two solar arrays capable of generating 400 watts.

“There’s more than 100 scientists and other personnel cooperating on the mission,” said Dr. Ricker, “and as far as the mission itself is concerned, all the work that was involved in designing, developing, and building the hardware, we’ve estimated that there’s more than a million person-hours that have gone into that over the past five years.”

Launch and Orbit:

The launch phase of the mission will see a Falcon 9 deliver TESS into a lunar transfer orbit, sending the craft to a precise point when the moon’s gravity will grab TESS and fling it out into a farther orbit than it’s initially launched into.

At 350 kg (772 lb), TESS is the lightest-known payload to have ever launched on a Falcon 9.  After lifting off from SLC-40 at the Cape Canaveral Air Force Station, FL, the Falcon 9 will fly due east from the pad.  The first stage, after 2 minutes 29 seconds of powered flight, will separate from the second stage and perform a landing on the Of Course I Still Love You drone ship in the Atlantic.  

.@NASA_TESS was encapsulated within the @SpaceX #Falcon9 fairing at @NASAKennedy. #TESS is on track for an April 16th launch attempt. pic.twitter.com/u05Jdt7Joy

— NASA_TESS (@NASA_TESS) April 13, 2018

SpaceX will also attempt to recover the payload fairing, but as there is no fairing catching boat – yet – on the east coast, the fairing will parachute into the ocean for intact recovery, serving primarily as a test of the new recovery systems.

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For the launch, after stage separation, the second stage will continue to fire its single MVac (vacuum optimized Merlin engine) until SECO-1 (Stage Engine Cut Off -1) at 8minutes 22 seconds into flight.  This will be followed by a 32 minute 33 second coast of the stage and TESS before the second stage engine re-starts for a burn to send TESS into a Lunar Transfer Orbit.

Shortly after SECO-2, TESS will separate from the top of the Falcon 9 second stage at 48 minutes 42 seconds after launch having been placed into a super synchronous transfer orbit of 200 x 270,000 km (124 x 167,770 mi).  The second stage will then perform a third burn to inject itself into a disposal hyperbolic (Earth-escape) orbit.

Over the first five days, TESS’s control teams will check out the overall health of the spacecraft before activating TESS’s science instruments 7-8 days after launch.  TESS will then perform a final lunar flyby on 16 May – one month after launch, a lunar gravity assist which will change the the craft’s orbital inclination to send it into its 13.7 day, 108,000 x 373,000 km (67,000 x 232,000 mi) science orbit of Earth – an orbit that is in perfect 2:1 resonance with the moon.

The maneuvers and encounters leading to the final TESS orbit (light blue). PLEA and PLEP are the post-lunar-encounter-apogee and -perigee, respectively. (Credit: Ricker et al. 2015)

The specific orbit, referred to as the P/2 lunar resonant orbit, will place TESS completely outside the Van Allen Radiation belts, with TESS’s apogee (farthest point in orbit from the Earth) approximately 90 degrees away from the position of the Moon.   This will minimize the Moon’s potential destabilizing effect on TESS and maintain a stable orbit for decades while also providing a consistent, good camera temperature range for the observatory’s operations.

Moreover, this orbit will provide TESS with unobstructed views of both the Northern and Southern Hemispheres.  For almost all of its orbit, TESS will be in data gathering mode, only transmitting its stored data to Earth once per orbit during the three hours of its closest approach to Earth, or perigee.  Assuming an on-time launch, TESS will enter operations on 12 June.

Overall, TESS has daily launch opportunities from 16-21 April, no launch opportunity on the 22nd (per NASA documentation), and then daily opportunities again from 23-26 April.  There is no opportunity on 22 April because the amount of time between the consecutive daily opportunities on 21 and 23 April is just slightly longer than 24 hours, thus barely skipping over all times on the 22nd.

However, if for some reason TESS is not off the ground by 26 April, the exoplanet hunter must stand down launch operations so that NASA’s Launch Services Provider (LSP) group can shift gears to support the agency’s InSight mission launch to Mars from Vandenberg Air Force Base, California.

Over the course of two years, our newest planet-hunter @NASA_TESS will scan 85% of the sky to find planets outside of our solar system, known as exoplanets. Watch & learn more about this mission launching on Monday: pic.twitter.com/zaHFrxyc5k

— NASA (@NASA) April 15, 2018

The LSP does not have a large enough staff to support two missions from both coasts, and since InSight has a short interplanetary launch window it must launch within, InSight would get priority over TESS.  After InSight, TESS has additional launch opportunities in both May and June.

Mission:

Once its checkout phase is complete, TESS will begin its 26 observational campaigns (13 for each hemisphere) to survey 85% of the sky for transiting exoplanets near Earth.  Observations will start with the Southern Hemisphere, and those 13 campaigns will last approximately one year.

According to Dr. Ricker, choosing to survey the Southern Hemisphere first was “a function of the follow-up resources that are currently available.  Many of the most powerful telescopes that ground-based astronomers use are located in the Southern Hemisphere.”

TESS will then be re-aimed to perform the 13 observational campaigns needed to cover the Northern Hemisphere.  During all 26 campaigns, the entire south and north polar sky regions will receive near-continuous year-long assessments from TESS’s cameras – as each observation campaign for the Southern and Northern Hemispheres overlap completely at their respective pole.

Dr. Ricker shows the number of transiting exoplanets TESS is predicted to find within 100 parsecs (326 light years) of Earth. (Credit: Chris Gebhardt for NSF/L2

Every 13.7 days, when TESS swings closest to Earth, the craft will downlink its observation data to scientists at MIT who will process it and make it available to other scientists and the public.  Specifically, TESS’s team will focus on the 1,000 closest red dwarf stars to Earth as well as nearby G, K, and M type stars with apparent magnitudes greater than 12.

Over its primary 2 year mission, TESS will observe about half a million stars in an area 400 times larger than the Kepler mission and is expected to find 20,000 exoplanets – including 500-1,000 Earth-sized planets and Super-Earths.

These planets will be added to the growing number of known exoplanets.  According to NASA’s Exoplanet Archive hosted by CalTech, as of 12 April 2018, there are 3,717 known exoplanets with 2,652 of those found by the Kepler Space Telescope.

TESS’s primary mission duration is two years, during which all of its science objectives are scheduled to be completed.  While a mission extension is never a guarantee, TESS can be extended for additional observations based on its design and orbit.  “We can extend, because the orbit will be operating and aligned for more than two decades,” said Dr. Ricker. “Now, as is the case for many Explorer missions, we fully expect that there will be an extended mission for TESS, so we pre-designed the satellite and the operation so that it can go on for a much longer time.”

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United Launch Alliance’s Atlas V rocket will carry out the AFSPC-11 mission for the United States Air Force Saturday, deploying the CBAS communications satellite and EAGLE technology demonstrator. Liftoff is scheduled for a launch window of undisclosed duration opening at 19:13 Eastern Time (23:13 UTC).

Saturday’s launch will see Atlas undertake a lengthy mission to inject its payloads directly into near-geostationary orbit, 35,786 kilometers (22,236 miles, 19,323 nautical miles) above the equator. The Air Force Space Command 11 (AFPSC-11) payload consists of two satellites which will separate from their carrier rocket over five-and-a-half hours after liftoff.

The primary payload for the AFSPC-11 mission is the Continuous Broadcast Augmenting SATCOM (CBAS) satellite. Few details of the CBAS mission have been made public. However, the spacecraft is known to be coordinated by the US Air Force’s Military Satellite Communications Directorate, who also manage the operational Wideband Global Satcom (WGS) and Advanced Extremely High Frequency (AEHF) communications programmes.

CBAS will serve as a communications relay for senior military commanders and augment the United States’ existing military satellite communications architecture.

Mission Patch – via ULA

Communications being vital in the modern battlefield, the US military operates a large and varied fleet of communications satellites. These include the Wideband Global Satcom (WGS) constellation that forms the backbone of the network, while the US Air Force’s Advanced Extremely High Frequency (AEHF) provides specialized protected communications.

The US Navy operates the Mobile User Objective System (MUOS), providing high-speed narrowband communications for mobile users. The National Reconnaissance Office operates its own fleet of relay satellites, the Satellite Data System (SDS), which supports its fleet of reconnaissance satellites.

In addition to these programmes, a number of legacy Defense Satellite Communications System (DSCS), Milstar and UHF Follow-On (UFO) satellites remain in service. These constellations have largely been replaced by WGS, AEHF and MUOS respectively.

CBAS is flying in the upper position for Saturday’s dual-satellite launch. The Air Force Research Laboratory’s ESPA-Augmented Geostationary Laboratory Experiment (EAGLE) satellite is mounted below it.

EAGLE has been built around an EELV Secondary Payload Adaptor (ESPA), which incorporates the separation mechanism for CBAS. This allows the two satellites to be stacked directly atop each other without the need for an additional payload adaptor such as the SYLDA used on dual-satellite Ariane 5 launches.

ESPA – via Orbital ATK

EAGLE was developed by Orbital ATK and hosts an array of technology demonstration payloads. The satellite is based on Orbital’s ESPAStar platform, which adds propulsion, power-generation and flight systems to an ESPA payload adaptor, turning it into a free-flying satellite. The core ESPAStar spacecraft has a dry mass of 430 to 470 kilograms (950 to 1,040 pounds), with a hydrazine-based monopropellant propulsion system mounted inside the payload adaptor ring with up to 310 kilograms (680 lb) of fuel.

The platform is three-axis stabilized and provides power via a 96 amp-hour battery and a deployable solar array, which will generate 1.2 kilowatts of power at the beginning of the satellite’s operational life.

On the outside of the ESPAStar platform’s adaptor ring, six hardpoints are available to mount payloads. Each hardpoint can accommodate a 181-kilogram payload (400-pound), either fixed to the satellite or a deployable subsatellite. EAGLE is the first mission to test the ESPASat bus, which is optimized for geostationary missions but can also be used in other orbits.

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EAGLE is a partnership between the AFRL and the Space Test Program (STP). It is carrying four fixed experiments and a deployable subsatellite. The fixed experiment packages are the AFRL-1201 Resilient Spacecraft Bus Development Experiment (ARMOR), Compact Environmental Anomaly Sensor III Risk Reduction (CEASE-III-RR), Hypertemporal Imaging Space Experiment (HTI-SpX) and the Inverse Synthetic Aperture LADAR (ISAL). These experiments are primarily geared towards developing space situational awareness and satellite inspection capabilities.

CEASE-III-RR will use a suite of instruments to identify conditions in the space environment that could affect the operation of a satellite. Consisting of high and low-energy proton/electron telescopes and an electrostatic analyzer, CEASE will measure the flux of charged particles in geostationary orbit, with this data being used to identify potential causes of anomalies in the spacecraft’s data or operation.

HTI-SpX will use a suite of visible-light, ultraviolet and medium and long-wave infrared imagers to collect data that will be used to demonstrate hypertemporal image processing techniques. This will see the satellite collect data over a long period of time, automatically identifying small changes that may warrant further attention. Developed by Raytheon, HTI-SpX will serve as a demonstrator for future long-term surveillance missions.

ISAL will demonstrate laser radar (LADAR) imaging of satellites in geostationary orbit. The payload consists of a synthetic aperture radar system, using the difference in velocity between EAGLE and its imaging target to increase its aperture size for imaging, resulting in higher-resolution images of the target.

The subsatellite, Mycroft, will be deployed from EAGLE at an unspecified future date. Mycroft is based around Orbital ATK’s ESPASat platform, designed specifically for deployment from the ESPA.

EPSASat – via Orbital ATK

This has a design life of three years. Measuring 56.6 by 56.6 by 70.0 centimeters (22.3 by 22.3 by 27.4 inches) before payload installation the bus has a dry mass of 70 kilograms (150 lb). It can carry up to 22.7 kilograms (50.0 lb) of hydrazine propellant and a thirty-kilogram (66 lb) payload.

The platform provides three-axis control with six degrees of freedom via reaction wheels and attitude control thrusters. It incorporates a 24 amp-hour lithium ion battery with a solar panel generating up to 265 watts of power. An ESPASat was previously used for the AFRL’s ANGELS experiment, which launched aboard a Delta IV in 2014 and was decommissioned last November.

AFSPC-11 will be launched by United Launch Alliance’s workhorse Atlas V rocket, flying in its 551 configuration. The rocket has tail number AV-079 and will be making the seventy-seventh flight of an Atlas V. One of the most reliable rockets in service worldwide, Atlas V has never lost a mission – the only blemish on its record a partial failure back in 2007 that left a pair of NRO ocean surveillance satellites in an incorrect orbit.

Atlas V 551 – via ULA

Developed by Lockheed Martin under the US Air Force’s Evolved Expendable Launch Vehicle (EELV) programme, Atlas V first flew in August 2002 when it deployed Eutelsat’s Hot Bird 6 satellite into geosynchronous transfer orbit. The rocket’s launches were originally contracted by International Launch Services – who had marketed the earlier Atlas II and III vehicles – however in 2006 operations were passed to the newly-formed United Launch Alliance (ULA).

ULA was created from the amalgamation of Boeing and Lockheed Martin’s space launch divisions and took over responsibility for manufacturing and launching Boeing’s Delta II and Delta IV vehicles, as well as Atlas V. ULA also took responsibility for marketing its rockets to US Government customers, while Boeing and Lockheed Martin retained the right to market their respective rockets for commercial launches. Earlier this year, United Launch Alliance announced that it had taken over marketing commercial Atlas launches – its Delta rockets are no longer available for commercial missions.

Atlas V is a two-stage rocket, consisting of a Common Core Booster (CCB) first stage and a Centaur upper stage. The rocket is able to fly in many different configurations – varying the size of its payload fairing, the number of engines on the Centaur stage and the number of solid rocket boosters clustered around the CCB – in order to accommodate different payloads. The 551 configuration that will be used for Saturday’s launch is the most powerful version to have been developed. A more powerful version of the rocket, Atlas V Heavy, would have used two additional CCBs strapped to either side of the central core, however this never left the drawing board.

Atlas V ahead of launch – via ULA

Saturday’s launch is the eighth time Atlas V has flown in the 551 configuration – which was first used in January 2006 to send NASA’s New Horizons spacecraft on its way to Pluto. The configuration was also used for 2011’s launch of the Juno mission to Jupiter and to deploy five MUOS communications satellites for the US Navy between 2012 and 2016. This version of Atlas V uses a five-meter (16-foot) diameter payload fairing, five solid rocket motors and a single-engine Centaur (SEC) upper stage. Three different lengths of five-meter fairing can be used on Atlas 5 missions – with the AFSPC mission using the shortest of the three. Built by Swiss firm RUAG, the fairing measures 20.7 meters (68 feet) in length and encapsulates Centaur as well as the payload.

The AFSPC-11 launch will take place from Space Launch Complex 41 (SLC-41) at the Cape Canaveral Air Force Station. Originally built for the Titan IIIC rocket in the late 1960s, SLC-41 went on to serve the Titan IIIE and Titan IV rockets, remaining in service for Titan until 1999. NASA’s Voyager missions to the outer planets, Viking missions to Mars and the Helios missions to study the Sun – the latter a joint venture with the German Aerospace Centre – launched from Complex 41 in the 1970s, while most of the other Titan launches from the complex carried military payloads.

With EELV rockets due to replace the Titan IV within the first few years of the 21st century, SLC-41 was transferred to the Atlas programme with Titan launches continuing from nearby Space Launch Complex 40 until 2005. Lockheed Martin wasted no time in converting the pad. In October 1999 – just six months after the last Titan IV had departed the complex – SLC-41’s fixed and mobile service towers were toppled in controlled explosions.

Atlas V initially used a clean-pad approach at the complex, with its umbilical tower attached to a mobile launch platform and all integration performed at the Vertical Integration Facility (VIF), a purpose-built tower 600 meters (9,970 yards) south of the pad. In recent years a fixed tower has been constructed at the launch complex housing a crew access arm to support future manned launches with Boeing’s CST-100 Starliner spacecraft. Starliner is expected to make its first, unmanned, test flight later this year.

SLC-41 – via ULA

SLC-41 was the site of Atlas V’s maiden flight in 2002 and was originally expected to be the rocket’s only launch pad. The former Atlas II launch pad at Vandenberg Air Force Base’s Space Launch Complex 3E (SLC-3E) was later converted to allow Atlas V to make higher-inclination launches. However, SLC-41 has been used for the majority of the rocket’s flights. Prior to the AFSPC-11 launch, SLC-41 had supported 27 Titan and 62 Atlas V missions, making Saturday’s launch the ninetieth mission to depart from Complex 41.

Saturday’s mission will begin with ignition of the Atlas Common Core Booster’s RD-180 engine, 2.7 seconds before the countdown reaches zero. Built by Russia’s NPO Energomash, the RD-180 is derived from the RD-170 family of engines originally developed for the Soviet Union’s Zenit and Energia rockets. A single engine with two combustion chambers and two nozzles, the RD-180 burns RP-1 propellant – rocket-grade kerosene – oxidized by liquid oxygen. Five Aerojet Rocketdyne AJ-60A solid rocket motors will augment the CCB at liftoff, igniting about T+1.1 seconds as the rocket lifts off.

Climbing away from Cape Canaveral, AV-079 will begin a series of pitch and yaw maneuvers 3.9 seconds into its mission, placing the rocket onto an 89.9-degree azimuth – almost due East – for the journey into orbit. Atlas will reach Mach 1, the speed of sound, 34.4 seconds after liftoff, passing through the area of maximum dynamic pressure – Max-Q – eleven-and-a-half seconds later.

Atlas V AFSPC-11 Mission Profile - YouTube

The AJ-60A boosters will burn for a little over ninety seconds before their thrust tails off and the boosters burn out. Two of the boosters will be jettisoned 107 seconds into the flight, with the remaining three separating a second and a half later.

The RD-180 engine will continue to burn as Atlas climbs out of the atmosphere. About three minutes and 31 seconds after liftoff the payload fairing will separate from the rocket. This structure, which encloses the upper stage and payload to protect them from the atmosphere and preserve the rocket’s aerodynamic qualities, is no longer needed once the vehicle reaches space and is jettisoned to reduce weight.

Shortly after the fairing separates the forward load reactor, a device attached at the top of the Centaur to stiffen the fairing and reduce vibrations, will also be jettisoned.

Atlas’ Common Core Booster will burn out four minutes and 33.5 seconds after liftoff – a milestone in the launch that is designated booster engine cutoff (BECO). The spent core is discarded, separating four seconds after BECO, with Centaur igniting its RL10C-1 engine ten seconds later.

Centaur on the Atlas V – via ULA

The cryogenically-fuelled Centaur burns liquid hydrogen and liquid oxygen. The stage traces its heritage back to the 1960s and the earliest Atlas-Centaur rockets, while Centaur has also flown aboard Titan rockets, was proposed for several other launch systems including the Saturn I and the Space Shuttle, and will be used – at least at first – as the second stage of United Launch Alliance’s next-generation Vulcan rocket.

Centaur will make at least three burns during Saturday’s launch as it carries AFSPC-11 into geostationary orbit. The first burn will last six minutes and 1.2 seconds, injecting itself into an initial parking orbit. After a twelve-minute, 6.7-second coast Centaur will restart as it passes over the west coast of Africa, making a five-minute, 48.9-second burn to place itself into a geosynchronous transfer orbit. Five hours and six minutes after the end of the second burn, after reaching geostationary altitude, Centaur will make a two-minute, 36.2-second burn to circularise its orbit and reduce its orbital inclination to zero.

United Launch Alliance has not confirmed the separation times for either CBAS or EAGLE, nor whether Centaur will undertake any further maneuvers between separation of its two payloads. After both satellites have separated, Centaur will place itself into a disposal orbit to reduce the chances of it colliding with a satellite in geostationary orbit. The mission is due to end at six hours, 57 minutes and 24.4 seconds elapsed time – one hour, twenty minutes and two seconds after the end of Centaur’s third burn.

Saturday’s launch is the third Atlas V mission of 2018, following successful launches in January and March that respectively carried the SBIRS-GEO-4 satellite for the US Air Force and GOES 17 for the National Oceanic and Atmospheric Administration (NOAA).

The next Atlas V launch is currently targeting 4 May out of California’s Vandenberg Air Force Base, with a mission to deploy NASA’s InSight lander bound for Mars. Atlas’ next East Cost launch is not currently expected until the end of August, when the rocket will carry Boeing’s Starliner spacecraft on its first unmanned test flight. The August launch will be the first flight of Atlas V with a dual-engine Centaur and the first not to use a payload fairing.

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Boeing, one of NASA’s two Commercial Crew providers, is making excellent progress toward the debut of their Starliner vehicle for both its uncrewed and crewed test flights.  In addition to the two planned certification missions, NASA has announced that Boeing’s Crew Flight Test, a two-week test mission, could now serve as a more operational six-month crew flight to the International Space Station with not two but three crew members.

Boeing makes progress toward OFT and CFT missions:

Officially, Boeing is targeting August 2018 for its Orbital Flight Test (OFT), their uncrewed certification mission for Starliner, to be followed in November 2018 with their Crew Flight Test (CFT).  Those dates are based on the last quarterly review by the Commercial Crew Program in February, and there is some indication that those dates are likely to slip at the next quarterly review in May – with the CFT slipping into 2019.

At the end of March, when Commercial Crew Program Director Kathy Lueders updated the NASA Advisory Council on commercial crew’s progress, she had high praise for Boeing, noting that “Boeing has been making tremendous progress.  They had their Launch Segment Design Certification Review with ULA (United Launch Alliance) last fall. “We had are ISS DCR (Design Certification Review) in December. And really, they’ve made tremendous progress towards baselining the open work that needs to be closed out before our upcoming CFT DCR that’s scheduled in the summer timeframe.”

Moreover, delivery schedules are now being worked with Boeing for delivery of their verification products, and Boeing is deep into hardware testing for the vehicles that will fly the OFT and CFT missions as well as undertaking a great deal of software training runs with a Johnson Space Center and the International Space Station Program – software needed to ensure proper flight, rendezvous, and docking with the Station.

Starliner docked to ISS, with Japan’s HTV resupply vehicle visible underneath the Columbus module. (Credit: Nathan Koga for NSF/L2)

“Right now, they’re working all our materials and out gas testing that’s really critical whenever you have a spacecraft that’s getting close to Station,” said Ms. Lueders.  “With Station we have to do all the material compatibility, and so the Boeing folks are working through that and making sure we’re meeting the Station requirements there.”

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Some of this activity includes a lot of work at White Sands Space Harbor, New Mexico, where Boeing is hot-fire testing its Service Module thrusters and preparing for the all-important launch pad abort test coming up in a few weeks.

“There’s a lot of activity going on at White Sands for the Boeing folks,” noted Ms. Lueders.  “They’ve been doing all the engine level testing for the crewed mission, for the CFT mission and then for PCMs (Post Certification Missions – standard crew rotation flights) -1 and -2.”

For Boeing, part of the ground certification for Starliner involves hot fire testing its Service Module engines, which the company is getting ready to perform at White Sands.  

“This is a critical activity that’s obviously testing out the Service Module portion of the vehicle but also provides data for our pad abort testing,” noted Ms. Lueders.

And the two become one….Launch Pad Abort Test is next pic.twitter.com/VSFEtJGAzM

— Christopher Ferguson (@Astro_Ferg) April 9, 2018

This launch pad abort test, which Boeing will perform in the coming weeks at White Sands, is critical in validating Starliner’s ability to successfully pull itself and its crew away from the top of an Atlas V rocket should a catastrophic failure of the Atlas V be detected while on the pad.

Recently, the two halves of the vehicle that will perform the pad abort test were joined together.  The pad abort test will see four launch abort engines and 20 orbital maneuvering engines fire to simulate an abort from the Atlas V.  Together, the engines will produce about 188,000 pounds of thrust for about six seconds to push the spacecraft to one mile (1.2 km) in altitude.

While technically just a pad abort test, the certification objective will also validate Starliner’s ability to free itself from the Atlas V at any stage during flight should an abort be needed. However, Boeing will not perform an in-flight abort test as one was not mandated by NASA as part of the Commercial Crew Program.

SpaceX and NASA have both opted to voluntarily conduct in-flight abort tests for their new crew vehicles to validate how Dragon and Orion, respectively, perform during potential aborts at MaxQ (moment of maximum mechanical stress on the vehicle during launch).

Starliner performs its pad abort test at White Sands Space Harbor, New Mexico. (Credit: Nathan Koga for NSF/L2)

For Boeing, the pad abort test will also provide an additional opportunity to test the parachute system Starliner will use to safely slow itself down for a land landing upon its return from space.  To date, Boeing has completed their second parachute system qualification test and have three additional qualification tests and six reliability drop tests planned, with three of those reliability tests utilizing balloons and three utilizing a long-dart shaped vehicle.

Moreover, Boeing is also making great progress on crew training.  “Not only is the hardware getting ready, but Boeing has outfitted and put together all of their trainers,” said Ms. Lueders.  “They have a Boeing mock-up trainer, and that outfitting was completed in January. And they’re in the midst of all the activities going on with crew training, all the checkouts that are needed to be able to get ready for not only crew training but also verification of the integrated system.”

This includes the Boeing Engineering Simulator, or BES, which is now operational with crew and Boeing test subjects working through different testing regimes.  “Really from a suite of simulators and different tools and from an operational perspective, the Boeing team has been really integrated and is starting to work through the flight planning and checkouts of the system,” noted Ms. Lueders.

Starliner flight vehicles and Atlas V preparations:

At the Kennedy Space Center, work is also progressing on Starliner spacecraft #3 which will fly the OFT uncrewed test flight in August 2018.  “Production operations are underway, and we are supporting lower dome first light that happened in mid-March,” updated Ms. Lueders.

Rocket Launch 360: Atlas V Starliner - YouTube

First light was the moment when Boeing first powered up Starliner #3, and that vehicle is now progressing through lower dome harness outfitting, side hatch assembly and build, base heat shield assembly, and primary structure for the service module and radiator support installation.

While Starliner #3 will fly first, Starliner #2 is actually ahead in terms of production, but Starliner #2 will be taken from Kennedy, once completed, to El Segundo, CA, for a series of acceptance and environmental tests and will be put through its paces to certify the overall Starliner design for flight.

Thus, Starliner #2 is not available for the OFT.  After its test regime, Starliner #2 will return to Kennedy and the C3PF (Commercial Crew and Cargo Processing Facility) where it will be put into flow for use as the first Starliner to carry people to space on the CFT mission.

In terms of the launch vehicles, AV-080 – the Atlas V for the OFT mission – is in flow at ULA’s (United Launch Alliance’s) Decatur, Alabama, production facility.  “AV-080 is really in the final stages of assembly,” said Ms. Lueders to the NASA Advisory Council. “The tanks have been joined, all the system integration and assembly and checkouts are done, and they’ve installed the RP-1 (rocket grade kerosene) feed line and engines.

Chris Ferguson, the final Shuttle Commander and now Director of Boeing’s Commercial Crew operations, stands before an Atlas V first stage at ULA’s Decatur, Alabama, production facility. (Credit: NASA)

“The Centaur (upper stage) has both pressure tanks completed, foam applications have been completed, and the engines delivered with verification testing is in work.  And then the forward adapter is complete less the coaxial cable installation. So that vehicle is coming along.”

The Atlas V that will launch the CFT crew mission is also in flow.  Its RP-1 tank is in final integration and assembly, and the LOX (Liquid Oxygen) tank has been delivered.  The Centaur is being assembled, and its two RL-10 engines have been delivered.

Starliner might get extended first crewed mission:

As part of the continued slippage of the first flights of both Starliner and crew Dragon, and an impending deadline in mid-2019 after which NASA has no purchased crew seats aboard the Russian Soyuz rocket and crew capsule, NASA has updated its Commercial Crew Transportation Capability (CCtCap) contract with Boeing to allow for the possibility of the CFT mission adding an additional crew member and extending the flight from 14 days to six months.

Exact details of how to best take advantage of the contract modification are under evaluation, but the changes could allow for additional microgravity research, maintenance, and other activities while Starliner is docked to Station.  “This contract modification provides NASA with additional schedule margin if needed,” said William Gerstenmaier, Associate Administrator, Human Exploration and Operations Mission Directorate. “We appreciate Boeing’s willingness to evolve its flight to ensure we have continued access to space for our astronauts.”  

Starliner launches atop an Atlas V N22 rocket from Cape Canaveral Air Force Station, FL, carrying new crewmembers to the International Space Station (Credit: Nathan Koga, for NSF/L2).

The current commercial crew flight schedules provide about six months of margin to begin regular, Post Certification Mission crew rotation flights to the Station before NASA’s contracted flights on Soyuz end in fall 2019.  

“Turning a test flight into more of an operational mission needs careful review by the technical community,” said Mr. Gerstenmaier.  “For example, the spacecraft capability to support the additional time still needs to be reviewed. Modifying the contract now allows NASA and Boeing an opportunity to tailor the duration to balance the mission needs with vehicle and crew capabilities.”

This would not be the first time NASA has expanded the scope of a commercial test flight.  NASA had SpaceX carry cargo on its commercial cargo demonstration flight to the ISS under the Commercial Orbital Transportation Services initiative in 2012, which was not part of the original agreement.

There is currently no known timeline for a decision on what to do about CFT’s crew complement and flight duration.  However, Steve Stitch, Deputy Manager for Flight Development and Operations with the Commercial Crew Program stated earlier this month that crew assignments for both Boeing’s CFT mission and SpaceX’s DM-2 crewed test flight of Dragon are expected in the “summer timeframe.”

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In a year that should see both SpaceX and Boeing conduct the uncrewed test flights of their respective crew launch vehicles, Space Exploration Technologies, SpaceX, is making good progress toward its commercial crew goals.  With specific launch target dates to be reevaluated next month at a standard quarterly review, SpaceX is currently aiming to conduct their uncrewed demo flight test of Crew Dragon followed by an in-flight abort test before the all-important crew flight test in the second half of this year.

SpaceX – Commercial Crew readiness continues for Dragon:

While the specific target dates for SpaceX’s three main Commercial Crew events are still under review and will be reevaluated in May at a standard quarterly evaluation with NASA’s Commercial Crew Program, SpaceX is currently targeting August for their uncrewed flight test of the crew Dragon vehicle, a test flight known as Demo Mission 1 (DM-1).

DM-1 will be followed by an in-flight abort test, where a crew Dragon will be mounted atop a Falcon 9 rocket with an abort triggered by Dragon’s onboard computers at the moment the vehicle reaches MaxQ (moment of maximum stress on the vehicle) during ascent.

Once those two milestones are complete, SpaceX aims to conduct a crew test flight of Dragon, known as DM-2.  This mission is currently slated for December 2018 but is likely to slip into early 2019.

SpaceX Pad Abort Test - YouTube

Together, the DM-1 and DM-2 flights for SpaceX serve as the company’s certification missions for the Commercial Crew Program, leading to the standard 6-month duration crew rotation flights to the International Space Station.  Those crew rotation flights are commonly known in the Commercial Crew Program as the Post Certification Missions, or PCMs.  Despite the fact that the Demo missions have not yet flown, NASA is already working with SpaceX on the planning for the first two PCM flights of the crew Dragon.

“A lot of work’s been done ensuring that the spacecraft is ready to be able to move toward progress toward the uncrewed and then the crewed mission,” noted Kathy Lueders, Program Manager NASA’s Commercial Crew Program, during a briefing to the most-recent NASA Advisory Council meeting at the end of March.

“We’ve been working through a major fire suppression campaign, making sure that [Dragon] and its systems are controlling that key hazard,” said Ms. Lueders while overviewing the recent progress SpaceX has made in the construction of the crew Dragon capsules for both the DM-1 and DM-2 missions.

Some of these activities have included installation of Dragon’s radiators and intermediate radiator build up, end-to-end comm suit system testing, and integrated suit testing inside the Dragon training module to make sure the integrated system is working.  Likewise, the critical C2V2 crypto-comm radio for vehicle communications is also undergoing testing in part to ensure that the effects of a water landing on the crypto-comm are understood – with the goal being that the water landing will not impact the comm system at all.

A cargo Dragon prepares for splashdown in the Pacific Ocean after a successful mission to the International Space Station. (Credit: SpaceX)

Intriguingly, given that NASA’s Mercury, Gemini, and Apollo programs all landed in water as will the Orion crew capsule, some discussion at the most recent NAC (NASA Advisory Council) update for commercial crew focused on SpaceX’s performance of water landings for crew Dragon and the agency’s lack of understanding of exactly how water landings will affect the crew.

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When prompted by a NAC member on the surprising nature of this statement, Ms. Lueders said, “We’ve been working towards really understanding how the water landings are going to be affecting the [crew].  From an environmental perspective, one of the things people are worried about was the landing from a wave perspective. So we’ve been working through exactly how we model where and under which conditions we’d exceed those certified loads on the vehicle.”  

The crux of the concern comes from understanding how the entire integrated system of the crew Dragon capsule performs under certain water landing conditions and making sure that the loads on the vehicle during various sea state conditions do not exceed the ability of the vehicle to protect the crew.

This led to a statement from Ms. Lueders that the Commercial Crew Program was working with SpaceX as well as Boeing to understand maximum sea state conditions for both Dragon and Starliner and the potential creation of Launch Commit Criteria for sea states in the down range abort zones underneath the flight track for both the Falcon 9 with Dragon and the Atlas V with Starliner.

Visiting Vehicles – Starliner, Dragon 2 and Dream Chaser – by Nathan Koga, L2 Render.

When those Launch Commit Criteria for sea states come to fruition, it will be the first time since the 1970s that crew launches from the United States will hold the potential of being scrubbed due to high or rough seas hundreds of miles down-range from the launch site for sea states that could imperil crew rescue and crew safety in the event of a launch abort.

Something that will greatly help and further the understanding of sea state conditions and their impact on overall integrated vehicle performance and crew safety will come this fall when SpaceX conducts their water landing tests.

Moreover, crew interface displays are also progressing.  “Crew displays is obviously a new capability the SpaceX folks are working through.  Our crew members have been working hand in glove with SpaceX, giving them their lessons learned on how to build their displays and evaluating their new systems as they’re bringing them on,” said Ms. Lueders.  “So step by step, the SpaceX folks are maturing and adding capabilities so that we can start beginning integrated system level test by the end of the summer.”

That systems-level testing will include Dragon’s propulsion module system.  “They’re doing an integrated system test of one of their [thruster] quads to make sure they understand the propulsion system dynamics as they’re running through different abort sequences and other stressing cases on their propulsion system,” noted Ms. Lueders.

In 2018, @Boeing & @SpaceX are making progress toward sending our astronauts to & from @Space_Station. Both partners are continuing to manufacture spaceflight hardware, test & prove that their systems meet @Commercial_Crew mission & safety requirements: https://t.co/EmTre34iK9 pic.twitter.com/Dz7hFJyLqp

— NASA (@NASA) February 9, 2018

Moreover, the avionics bay for the DM-1 Dragon is fully populated and is going through checkouts.  All cabin support equipment and propulsion components are installed. Final installation is also underway on the ECLSS (Environmental Control and Life Support System) as well as the oxygen and nitrox delivery panels.

As far as the crew dragons ability to generate its own power, 120 of the 240 solar arrays have been completed and are in the process of being installed onto the DM-1 vehicle.  Overall, the docking system build for DM-1 is 90% complete and underwent testing at the Johnson Space Center prior to being installed on the vehicle for flight.

At this point, the crew Dragon for DM-1 will be shipped to Plum Brook Station for environmental testing at the end of May.

Falcon 9 and LC-39A:

For SpaceX, the prime consideration for the DM-1 mission is not solely the crew Dragon capsule but also the Block 5 version of the Falcon 9 that incorporates all of NASA’s asked for upgrades, including new engine turbines and upgraded COPV (Composite Overwrap Pressure Vessel) designs.

First Block 5 on the McGregor Test Stand on Monday – via Gary Blair for NSF/L2

Ms. Lueders noted that the crew configuration qualification for the Merlin 1D engines are underway, and the new Octoweb 3.0 design that houses the 9 Merlin 1Ds at the base of the Falcon 9 first stage has successfully completed ground test requirements.

Moreover, the Block 5 will consist of the new COPV 2.0 design for the helium bottle pressurization system.  These systems will all fly on the first Block 5 mission next month that will loft the Bangabandhu-1 satellite for Bangladesh into orbit.  For the specific Falcon 9 vehicle that will launch the DM-1 flight, Ms. Lueders related that this vehicle is in flow at SpaceX’s production facility in Hawthorne, California, with both of Stage 1’s tanks in vertical integration and COPV installation.

Presently, the DM-1 vehicle is understood to be Falcon 9 first stage number B1051.  The Falcon 9 that will launch the DM-2 mission is also in manufacturing at this time, with the propellant tanks currently being welded.

As for the launch pad, most work to convert LC-39A for crew readiness was halted as SpaceX focused on its Falcon Heavy demo campaign.  Once that mission was away in early February, work resumed to finish converting Pad-A for commercial crew readiness.

Most notably, this has included completion of removal of the Rotating Service Structure (RSS) from the Space Shuttle era, with the most recent photos showing most if not all of the RSS removal process complete.

The removal of the RSS at 39A

While the RSS was vital for the Shuttle program, it is unnecessary for SpaceX’s use of the pad, and demolition of the structure was preferred over the cost of maintaining the massive hunk of steel in a salt air environment by the Atlantic Ocean.

Once the RSS is completely removed, pad teams will begin work to raise the slide wire basket escape system from the 195 ft level of the Fixed Service Structure (FSS) tower to the top of the FSS.  The slide wire basket system was installed at pad 39A at the beginning of the Space Shuttle program for emergency use by final launch preparation teams and/or flight crews in the event that the need to quickly evacuate pad arose.

The same system will be utilized on Pad-A for SpaceX’s crewed missions of the Falcon 9, but as the Falcon 9 places the Dragon capsule far higher than the Shuttle’s crew cabin in terms of location along the FSS, the baskets must now be moved to the top of the tower.  When asked by NASASpaceflight’s Chris Gebhardt when that operation would begin, NASA said they were uncertain but expected the process to commence within the next few months.

Moving the slide wire baskets is not the only addition to the FSS needed for SpaceX’s crewed missions.  Installation of the crew access arm must also take place before the crewed DM-2 flight later this year.  Current schedules presented to the NASA Advisory Council late last month show that installation of the crew access arm at LC-39A will occur in autumn of this year between the DM-1 and DM-2 flights.

(A second Commercial Crew Program update focusing on Boeing’s Starliner will be published tomorrow.)

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In the latest of a series of Request For Information (RFI) filings, NASA has called for alternative options to the RS-25 engine that will power the core stage of the Space Launch System (SLS). The RFI appears to be aimed at engines to be used after the RS-25Ds left over from the Space Shuttle era – and some already purchased RS-25Es – have been used up, although the requirements section all-but ensures new RS-25s – the expendable version that is already being worked on – will remain the engine of choice.

The Space Launch System (SLS) is a “Shuttle Derived Heavy Lift Launch Vehicle” – or SD HLV, as requested via the 2010 Authorization Act that gave birth to the vehicle design as NASA moved away from the failing Constellation Program (CxP) and its Ares rockets.

While the design of SLS went through a number of rigorous reviews – via the RAC (Requirements Analysis Cycle) effort – which allowed alternative rockets to be considered as NASA’s next HLV, the political direction heavily weighted the decision-making process towards using existing technology from the Shuttle era.

Slide used during the RAC to show many rockets were considered to become SLS – NASA/L2

Although that continues to be referenced by detractors, the plus side is the rocket will be making use of proven technology that has a rich heritage from the Shuttle era, not least the final salvo of flights that saw flawless performance from the final iterations of the RS-25 and Solid Rocket Boosters (SRBs).

However, that heritage also includes the large costs associated with the Shuttle program, which have – despite some streamlining – fed into the SLS program.

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With NASA having large amounts of success in utilizing commercial companies that compete against each other for NASA contracts, the RFI and RFP (Request For Proposals) route has become increasingly popular in trying to create a competitive environment with SLS contracts, with the aim of reducing overall costs to the NASA budget line.

However, with SLS locked into a very specific design, that has proven almost impossible with the rocket. The latest RFI provides another example that one person involved with SLS told NSF was “like the Russian Presidential election. You have to have one, but there’s only going to be one winner.”

SLS’ first four flights have engine assignments based on the stock of RS-25s, most of which were handed over from the Shuttle program. The RFI is looking for an additional 18 engines to cover flights in the second half of the 2020s.

The current stock of RS-25Ds – via NASA

The LEO (Liquid Engine Office) at the Marshall Space Flight Center (MSFC) is seeking potential sources to provide the Core Stage Engines (CSEs) in support of the flight manifest,” noted the RFI.

“The SLS vehicle architecture is documented and it is expected that the first four CSEs (from this next contract) will be required to be delivered by July 2025. The CSE currently in this architecture is the RS-25 engine (derived from the Space Shuttle Main Engine). The early SLS flights will utilize RS-25 engines.”

However, those sources must conform to numerous requirements that rule out most – if not all – of the more obvious contenders to the RS-25.

“NASA is seeking CSE design sustainability, manufacturing, assembly, test, analysis, certification, and flight support capabilities that can meet its technical and programmatic constraints. The engines must meet or exceed the performance, interface, and reliability requirements of the current RS-25 engine to avoid costly impacts to the vehicle and core stage design.

“As such, the engines must be certified to meet the current RS-25 functional,human-rating and performance requirements, match interface conditions and design configurations, and operate within all natural and induced environmental constraints.”

The specific requirements on the RFI

The general requirements refine the request down to a near-match of the RS-25.

The RFI and its timing are strange, given it’s been no secret SLS wants the RS-25 to be the engine of choice for the long-term.

Back in 2015, NASA awarded Aerojet Rocketdyne over a billion dollars to restart production capability for the RS-25, focusing on the RS-25E – the expendable version of the engine. This also included an order for six additional engines, for a total cost of around $1.5 billion. A decision to move away from the RS-25 in the second half of the 2020s would effectively mean NASA paid $1.5 billion for six engines.

RS-25’s firing on the core stage of SLS – as envisioned by Nathan Koga for NSF/L2

NASA issued a “Justification for Other Than Full and Open Competition (JOFOC)” in accordance with the Federal Acquisition Regulation (FAR) as a result of the sole-source nature of the deal.

The JOFOC literally ruled out any other engine for SLS’ core, which would likely be used in future reasoning if a company somehow managed to propose an alternative to the RS-25 via the latest RFI.

The total engine stock, based on Shuttle’s “hand-me-down” engines, an additional stock created from spare parts, and the six engines ordered via Aerojet Rocketdyne would support SLS’ first five missions, taking into account the need for flight spares, etc.

The four RS-25s – all Shuttle veterans – that will launch the EM-1 SLS mission

As such, the RFI is focused on at least the sixth SLS flight onwards, but only a re-order from Aerojet Rocketdyne makes sense per the requirements and the money already invested in the re-start of production facilities.

A huge amount of work has already taken place on refining the engines for their next role, with numerous test firings at the Stennis Space Center already conducted – with more to come. The engines have also gained additional upgrades via the use of 3D printed parts and upgraded engine controllers.

The engines are preparing for the upcoming milestone of the Green Run test, which will be conducted on the modified B-2 test stand at Stennis. This will be the first time four RS-25 engines – on the first Core Stage – will be fired for a full mission duration of approximately 500 seconds.

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India will launch a new satellite for its NavIC satellite navigation system Thursday, replacing a faulty spacecraft in orbit seven-and-a-half months after its intended replacement was lost at launch. The PSLV rocket is set to loft the IRNSS-1I from the First Launch Pad of the Satish Dhawan Space Centre, will occur at 04:04 local time (22:34 UTC on Wednesday).

The Navigation with Indian Constellation, or NavIC, system – also known as the Indian Regional Navigation Satellite System (IRNSS) – consists of multiple satellites deployed into geosynchronous orbit to give India its own dedicated satellite navigation system.

Serving both military and civilian needs, NavIC relies on seven satellites broadcasting highly-accurate timing signals that a receiver can use to triangulate its location.

Three of NavIC’s satellites are positioned in equatorial geostationary orbits, while the remaining four satellites are in geosynchronous orbits inclined by about 28 degrees to the equator. The geostationary satellites each have their own orbital slot, while the inclined-orbit spacecraft operate in pairs.

IRNSS-1I – via ISRO

IRNSS-1I will enter an inclined orbit, making a figure-eight around a point on the equator at a longitude of 55 degrees East. The IRNSS-1A and IRNSS-1B satellites currently occupy this slot.

The IRNSS-1I satellite which will be carried by Thursday’s launch is the ninth spacecraft to be launched by the Indian Space Research Organisation (ISRO) for the project.

It is the second of two satellites that were originally built as ground-spares for the project, but which were pressed into service because of reliability issues with the atomic clocks aboard the spacecraft already in orbit.

The first ground-spare, IRNSS-1H, was lost in a launch failure last August, when the payload fairing of the PSLV-XL rocket that was carrying it to orbit failed to separate.

Buildup of India’s GPS constellation – via UPSCCONNECT

NavIC’s first satellite, IRNSS-1A, was launched in July 2013. Three years into what was expected to be a ten-year mission, one of the three atomic clocks aboard the satellite failed. The spacecraft’s other two clocks failed over the next six months, leaving it unable to broadcast navigation data.

While IRNSS-1A remains on-station to broadcast system messages to the constellation’s user, last August’s IRNSS-1H launch was to have replaced it with a new, healthy, satellite. With its failure, IRNSS-1I will now take on this role.

Even before IRNSS-1H was lost, IRNSS-1I was being prepared for launch in late 2017 or early 2018, in order to provide extra redundancy on orbit should another satellite malfunction.

ISRO’s four-stage Polar Satellite Launch Vehicle (PSLV) will deliver IRNSS-1I to orbit. The PSLV, which will fly in its most powerful PSLV-XL configuration, uses a mixture of solid and liquid propellants.

PSLV first flew in September 1993 – its maiden flight failing to deploy the IRS-1E remote sensing satellite after a guidance problem. The maiden flight is one of only two outright failures that the PSLV has suffered – the other being the loss of IRNSS-1H last August when the rocket’s payload fairing failed to separate – in forty-two launches prior to Thursday’s mission.

PSLV also recorded a partial failure in 1997, placing the IRS-1D satellite into a lower-than-planned orbit after a helium leak on the fourth stage.

PSLV launches take place from ISRO’s Satish Dhawan Space Centre, located on Sriharikota Island, about seventy kilometers (45 miles) north of Chennai.

Satish Dhawan Space Centre

The center, named the Sriharikota High Altitude Range prior to 2002, has been used for all of India’s orbital launches. Two launch pads are currently used for orbital missions – the First Launch Pad is used for PSLV launches, while the Second Launch Pad also accommodates the PSLV, as well as the larger GSLV Mk.II and GSLV Mk.III. Thursday’s launch will use the First Launch Pad.

Despite its name, the First Launch Pad is not the oldest launch complex at the Satish Dhawan Space Centre – it is a separate complex to the pads used for India’s earlier launches with the smaller SLV and ASLV rockets. When launching from the First pad, PSLV rockets are stacked vertically directly atop the launch pad, with the aid of a mobile service tower. The tower was moved away from the launch pad prior to PSLV’s thirty-two-hour-long countdown getting underway on Tuesday.

The rocket that will perform Thursday’s launch has the flight designation PSLV C41. In its PSLV-XL configuration, it consists of a four-stage PSLV core vehicle with six PS0M-XL solid rocket motors strapped to the first stage. Four of the PS0M-XL motors light while the rocket is still on the launch pad, while the remaining pair ignite a few seconds into the flight.

At the conclusion of the countdown on Thursday, PSLV’s first stage will ignite. The first pair of boosters will fire 0.42 seconds after the first stage, with the second pair igniting two tenths of a second later. The solid-fuelled first stage, designated PS1, consists of a single S-138 motor which will burn for about 113 seconds. Each PS0M-XL has an S-12 solid rocket motor.

The boosters on the PSLV for this launch – via ISRO

PSLV’s air-lit boosters will ignite twenty-five seconds after liftoff, with the rocket already at an altitude of 2.7 kilometers (1.7 miles, 1.5 nautical miles). The ground-lit solids will burn until a little under seventy seconds into the mission, separating in pairs at 69.9 and 70.1 seconds mission elapsed time. Following their own burnout, the air-lit motors will separate at the 92-second mark in Thursday’s flight.

With the boosters gone, PSLV C41’s core stage will continue to power the rocket towards space. The stage will burn for a further 18.2 seconds before separating, with second stage ignition due to take place two tenths of a second after staging.

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PSLV uses a liquid-fuelled second stage – designated PS2 or L-40 – which is powered by a single Vikas engine. For Thursday’s launch a standard Vikas will be used, not the upgraded version that ISRO first tested during last month’s GSLV launch. Vikas – derived from the French Viking engine that powered the European Ariane 1, 2, 3 and 4 rockets – burns UH25 propellant and dinitrogen tetroxide.

One minute and 32.8 seconds into the second stage’s burn, PSLV’s payload fairing will be commanded to separate. The fairing, termed a “heat shield” by ISRO, protects PSLV’s payload as the rocket climbs through Earth’s atmosphere. With the rocket now in space, at an altitude of about 113 kilometers (70 miles, 61 nautical miles), the fairing is no longer needed and is discarded to save weight. During last August’s IRNSS-1H launch, part of the fairing separation mechanism failed to pressurize, resulting in the fairing remaining attached to the rocket.

Carrying the extra mass of the fairing for the remainder of its flight resulted in August’s launch attaining a lower-than-planned orbit. When IRNSS-1H separated from the rocket, it was still contained within the fairing, unable to maneuver or deploy its solar arrays or antennae. Since the IRNSS-1H failure, ISRO has conducted one more successful mission with the PSLV. The rocket returned to flight in January with the successful deployment of the Cartosat-2F remote sensing satellite.

A minute after fairing separation, the second stage will cut off and separate. The solid-fuelled PS3 third stage will ignite its S-7 motor 1.2 seconds after separation to continue the ascent. The third stage burn will last about seventy seconds and will be followed by a short coast.

Launch Profile after 1-2 Staging – via ISRO

Nine minutes and 58.72 seconds after liftoff, PSLV’s third stage will separate. The fourth stage will ignite ten seconds later, with its single burn expected to last eight minutes and 33.9 seconds. The fourth stage – known as PS4 or L-2.5 – is liquid-fuelled and burns monomethylhydrazine and mixed oxides of nitrogen.

IRNSS-1I will separate from the PSLV about 37 seconds after the fourth stage completes its burn, at 19 minutes, 19.6 seconds mission elapsed time. Thursday’s launch is targeting a sub-synchronous transfer orbit of 284 by 20,650 kilometers (76 x 12,830 miles, 153 x 11,150 nautical miles), with an inclination of 19.2 degrees. IRNSS-1I will use its own propulsion system to maneuver to its operational geosynchronous orbit, with a delta-V – or total velocity change – of about 1.89 kilometers per second (1.19 miles per second) required to accomplish this.

Thursday’s launch is India’s third of 2018 and comes less than a fortnight after the country’s previous launch – which saw a GSLV Mk.II rocket deploy the GSAT-6A communications satellite. Although GSAT-6A was deployed successfully by the GSLV, ISRO lost contact with it shortly after launch, just after the satellite had completed a planned orbit-raising maneuver.

Engineers are now fighting to save the GSAT-6A mission. However, ISRO has confirmed that they have no concerns that IRNSS-1I could be affected by a similar problem. The thirteen-and-a-half days between the GSLV mission and Thursday’s PSLV launch will be the shortest turnaround that ISRO has yet achieved between two launches.

After Thursday’s launch, ISRO’s next mission is another PSLV launch that is expected around the end of May. While the primary payload for this launch has not yet been announced, it is understood to be targeting a sun-synchronous orbit and will carry secondary payloads including the Global-1 microsatellite for US Earth imaging firm BlackSky.

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Aiming for a record-breaking year, the Chinese have successfully launched the Yaogan Weixing-31-01 mission – consisting of three satellites – from the Jiuquan Satellite Launch Center at 04:25 UTC on Tuesday morning. The surprise launch also carried another small – if unnamed – satellite. The launch took place from Launch Pad 94 of the LC43 launch complex using the Long March 4C (Y25) rocket.

The Yaogan Weixing-31-01 mission is composed of three satellites, with Chinese media referring to the new satellites to be used “for electromagnetic environment surveys and other related technology tests.”

The designation of the Yaogan Weixing series is used to hide the true military nature of the satellites.

In particular, this mission is similar to the Yaogan-9, 16, 17, 20 and 31 with three satellites flying in formation like a type of NOSS system, considered as the Jianbing-8 military series.

Designed for locating and tracking foreign warships the satellites will collect the optical and radio electronic signatures of the maritime vessels that will be used in conjunction with other information valuable for the Chinese maritime forces.

Chinese TV video of a previous launch of this satellite range

Yaogan-9 was launched on March 5, 2010, while Yaogan-16 was launched on November 25, 2012; Yaogan-17 was launched on September 1st, 2013, Yaogan-20 launched on August 9, 2014, and Yaogan-25 was launched on December 10, 2014.

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Together with the three Yaogan-30-01 satellites was launched a micro/nano technology test satellite. No specific designation was given to the small satellite.

This launch was the 271st launch of the Long March launch vehicle family and the 11th orbital this year.

With its main commonality matched to the Long March 4B, the first stage has a 24.65 meter length with a 3.35 meter diameter, consuming 183,340 kg of N2O4/UDMH (gross mass of first stage is 193.330 kg).

The vehicle is equipped with a YF-21B engine capable of a ground thrust of 2,971 kN and a ground specific impulse of 2,550 Ns/kg. The second stage has a 10.40 meter length with a 3.35 meter diameter and 38,326 kg, consuming 35,374 kg of N2O4/UDMH.

It includes a YF-22B main engine capable of a vacuum thrust of 742 kN and four YF-23B vernier engines with a vacuum thrust of 47.1 kN (specific impulses of 2,922 Ns/kg and 2,834 Ns/kg, respectively).

The Long March 4C launches the three satellites – via Chinese social media

The third stage has a 4.93 meter length with a 2.9 meter diameter, consuming 12,814 kg of N2O4/UDMH. Having a gross mass of 14,560 kg, it is equipped with a YF-40 engine capable of a vacuum thrust of 100.8 kN and a specific impulse in vacuum of 2,971 Ns/kg.

The Jiuquan Satellite Launch Center, in Ejin-Banner – a county in Alashan League of the Inner Mongolia Autonomous Region – was the first Chinese satellite launch center and is also known as the Shuang Cheng Tze launch center.

The site includes a Technical Centre, two Launch Complexes, Mission Command and Control Centre, Launch Control Centre, propellant fuelling systems, tracking and communication systems, gas supply systems, weather forecast systems, and logistic support systems.

The Jiuquan Satellite Launch Center

Jiuquan was originally used to launch scientific and recoverable satellites into medium or low earth orbits at high inclinations. It is also the place from where all the Chinese manned missions are launched.

The LC-43 launch complex, also known as South Launch Site (SLS) is equipped with two launch pads: 91 and 94. Launch pad 91 is used for the manned program for the launch of the Long March-2F launch vehicle (Shenzhou and Tiangong).

Launch pad 94 is used for unmanned orbital launches by the Long March-2C, Long March-2D and Long March-4C launch vehicles.

Other launch zones at the launch site are used for launching the Kuaizhou, Kaituo and the Long March-11 solid propellant launch vehicles.

The first orbital launch took place on April 24, 1970 when the Long March-1 rocket launched the first Chinese satellite, the Dongfanghong-1 (04382 1970-034A).

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