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Boeing CST-100 Starliner Successfully Tests Pad Abort System

For years, NASA has been working to restore their launch capability to the US and send astronauts to the Moon and beyond. A crucial part of this is the development of next-generation crew capsules that can carry crews and payloads to space. These include Lockheed Martin’s Orion Multi-Purpose Crew Vehicle (MPCV) and the Crew Space Transportation (CST) -100 Starliner currently being developed by Boeing.

On Monday 4 November, the CST-100 passed a critical milestone with a successful end-to-end test of its abort system. The Pad Abort Test took place at Launch Complex 32 at the US Army’s White Sands Missile Range in New Mexico. When crewed missions to space begin using the CST-100, this system will ensure that astronauts will be carried to safety in the unlikely event of an emergency before lift-off. The Rocketdyne RS-88 (Bantam) engine was used for its launch escape system.

The successful test began at 09:15 AM EST (16:15 local SA Time) and was live-streamed by NASA Television (video available below). The test was part of NASA’s Commercial Crew Program, a joint effort between NASA and the US aerospace industry to develop spacecraft and launch systems that will be capable of carrying crews to Low-Earth Orbit (LEO) and the International Space Station (ISS).

“Tests like this one are crucial to help us make sure the systems are as safe as possible. We are thrilled with the preliminary results, and now we have the job of really digging into the data and analysing whether everything worked as we expected.”

This was the first of many tests for the Starliner, which not only verified that each of Starliner’s systems will function separately but also in concert to protect astronauts. The entire process took only 95 seconds between the moment when the simulated abort began and when the crew module touched down on the ground again.

It all started when the Starliner’s four launch abort engines – as well as its orbital manoeuvring and attitude control thrusters – ignited and rapidly pushed the spacecraft away from the test stand. Five seconds into the test, the abort engines shut off as planned and steering was transferred to the control thrusters, which fired for the next five seconds.

The Starliner reached a peak altitude of 4,500 ft and conducted a pitch around manoeuvre, where it rotated in the air, before commencing its landing. Less than half a minute into the test, two of the three main parachutes deployed and the service module separating from the crew module. By the one-minute mark, the Starliner’s heat shield was released, its airbags inflated, and the spacecraft slowly descended to the ground.

While one of the parachutes failed to deploy, two out of three is acceptable as far as test parameters and crew safety are concerned. One concern was the cloud of, red coloured, noxious gas the was emitted form the service modual which landed very close to the crew capsule.

John Mulholland, Vice President and Program Manager of Boeing’s Commercial Crew Program, explained the significance of this test in a recent NASA press release:

“Emergency scenario testing is very complex, and today our team validated that the spacecraft will keep our crew safe in the unlikely event of an abort. Our teams across the program have made remarkable progress to get us to this point, and we are fully focused on the next challenge, Starliner’s uncrewed flight to demonstrate Boeing’s capability to safely fly crew to and from the space station.”

The next step in the Starliner’s development is the Orbital Flight Test, which is scheduled to take place on 17 December. This test will see an uncrewed Starliner being launched atop a United Launch Alliance (ULA) Atlas V rocket from Space Launch Complex 41 at the Cape Canaveral Air Force Station in Florida.

The CST-100 is assembled and processed at the Commercial Crew and Cargo Processing Facility (C3PF) at NASA’s Kennedy Space Center in Florida. Once fully-tested and verified, it will join the SpaceX Crew Dragon and begin to send astronauts to the ISS from American soil.

The design draws upon Boeing's experience with NASA's Apollo, Space Shuttle and ISS programs as well as the Orbital Express project sponsored by the Department of Defence. The CST-100 has no Orion heritage, but it is sometimes confused with the earlier and similar Orion-derived Orion Lite proposal that Bigelow Aerospace was reportedly working on with technical assistance from Lockheed Martin. It will use the NASA Docking System for docking and use the Boeing Lightweight Ablator for its heatshield. The Starliner's solar cells will provide more than 2,900 watts of electricity, will be placed on top of the micro-meteoroid debris shield located at the bottom of the spacecraft's service module.

It is designed to be compatible with multiple launch vehicles, including the Atlas V, Delta IV, and Falcon 9, as well as the planned Vulcan. Unlike earlier U.S. space capsules, the CST-100 will make airbag-cushioned landings on the ground rather than into water. Five landing areas are planned in the Western United States, which will give the CST-100 about 450 landing opportunities every year.

The CST-100 name was first used when the capsule was revealed to the public by Bigelow Aerospace CEO Robert Bigelow in June 2010. The letters CST stand for Crew Space Transportation. Although it has been reported that the number 100 in the name stands for 100 km, the height of the Kármán line which is one of several definitions of the boundary of space, the naming was in fact an arbitrary designation created by the corporate office.

In July 2010, Boeing stated that the capsule could be operational in 2015 with sufficient near-term approvals and funding, but also indicated they would proceed with development of the CST-100 only if NASA implemented the commercial crew transport initiative that was announced by the Obama administration in its FY11 budget request. Boeing executive Roger Krone stated that NASA investment would allow Boeing to close the business case, while this would be very difficult without NASA. In addition, a second destination besides the ISS would be needed to close the business case and Krone said that cooperation with Bigelow was crucial for this.

Boeing was awarded a $92.3 million contract by NASA in April 2011 to continue to develop the CST-100 under CCDev phase 2. On August 3, 2012, NASA announced the award of $460 million to Boeing to continue work on the CST-100 under the Commercial Crew Integrated Capability (CCiCap) Program.

In April 2018, NASA suggested the first planned two-person flight of the CST-100 Starliner, slated for November 2018, was now likely to occur in 2019 or 2020. If the delays are maintained it would be expected to carry one additional crew member and extra supplies. Instead of staying for two weeks as originally planned, NASA said the expanded crew could stay at the station for as long as six months as a normal rotational flight.