Boeing space capsule: Starliner before the first manned test flight

On Monday, May 6, at 10:34 PM local time (Tuesday, May 7, 4:34 AM CEST) the time has finally come: a Boeing CST-100 Starliner is scheduled to fly a crewed vehicle to the International Space Station (ISS). ). for the first time. On board: NASA astronauts Barry “Butch” Wilmore (61) and Sunita “Sonny” Williams (58). Atlas V brings the new US spacecraft into space from Space Launch Complex-41 at Cape Canaveral Space Force Station in Florida. Alternate start dates are May 7, 10 or 11. The approach to the International Space Station must take place 24 hours after launch.

The Crew Flight Test (CFT) to the International Space Station is an important milestone in the program, which has been delayed for years. At the end of a four-year competition, Boeing and SpaceX won a contract from NASA in September 2014 to transport astronauts to the International Space Station as part of the “Commercial Crew Transport Capability Contracts.” Boeing received $4.2 billion, and SpaceX received $2.6 billion. A minimum of two trips and a maximum of six trips per provider were initially planned. It was said at the time that the first transfers to the space station were scheduled to begin at the end of 2017.

This was not possible due to technical problems. In May 2016, Boeing had to postpone its first crewed flight, and SpaceX followed suit a few months later. 2018 was the new goal. Ultimately, SpaceX couldn't do it either. But Crew Dragon made its first test launch to the International Space Station with a crew on May 30, 2020, and has so far conducted eight commercial flights for NASA.

The problems are triggered by the software

It has been a long way to go before the first manned test flight of a Boeing capsule: the first unmanned test (orbital flight test, OFT) in December 2019 was a failure. At that time, the capsule did not reach the International Space Station due to software errors and communication problems, but it was able to land in White Sands, New Mexico, two days after liftoff. After the failure, an independent panel of experts recommended massive improvements to the Starliner.

Boeing planned a second unmanned test flight (OFT-2) at its own expense, which has been postponed several times. Finally, a date was set for August 2021. Starliner was already integrated into the Atlas V launch vehicle when the flight test had to be cancelled. Reason: Corrosion of more than ten fuel valves in the service unit. A new attempt by OFT-2 was finally successful on May 20, 2022. On the way to the ISS, two of the capsule's engines failed, but due to the current iteration, the Starliner reached the space station as planned. The spacecraft remained docked with the ISS for about five days, finally landing at White Sands on May 25.

However, a month before the CFT was planned for July 2023, other problems were discovered with the Starliner: the required safety factor was not present in the attachment of the main parachute elements and brake parachutes, and the adhesive tape used on the capsule posed a fire risk under certain conditions. conditions.

Flight readiness was reviewed

The so-called “soft links” of parachutes, which are rings made of Kevlar, have been redesigned. Boeing was also waiting for a new parachute configuration that was already planned for the first commercial flight (Starliner-1). The new parachute from supplier Airborne Systems was tested at the beginning of January.

More than 90 percent of the offending P-123 tape, totaling more than 1,000 meters, has been removed. Barriers and protective coatings have been developed for areas where P-123 tape cannot be removed because it may cause damage. The glass cloth tape is actually intended to protect cables from scratches and abrasion.

But Boeing wants to put the problems behind them by the time it passes its flight readiness review at the end of April. “We can conclude that confidence in the system is high,” Mark Nappi, vice president and director of the Commercial Crew Program at Boeing, said at a news conference on April 25. “We are ready to fly.”

The focus now is on the manned test flight

The CFT uses the capsule that completed its first unmanned test flight. The images show areas scorched by reentry into Earth's atmosphere. “The outside of the spacecraft is protected by a thermal blanket,” Nappi said. “The blanket is still very practical and adds character to the spacecraft. So we decided to leave it.”

CFT now aims to show how spacecraft behave with respect to people. Wilmore and Williams also have to fly manually. The mission is expected to last just under two weeks. The two astronauts are then supposed to return to Earth with the capsule and land at White Sands, on land and not in water like the Crew Dragon. “This is a test flight and we expect to learn a lot from it,” Nabi said in a press conference at the end of March.

The CFT data will then be evaluated and work will be carried out to obtain commercial approval for the Starliner vehicle, which should take place in November or December. The Starliner-1 mission with NASA astronauts Scott Tingle and Mike Finke, as well as Canadian Joshua Kotric and a yet-unidentified fourth member, is scheduled to launch to the International Space Station in the spring of 2025 at the earliest. On April 25, Nappi did not want to talk about what would happen after the six planned flights to the International Space Station. “The focus now is on financing terrorism,” he said. It is expected to be at full capacity until the end of the decade and until the end of International Space Station operations, with one flight scheduled per year. “We have a lot of time to think about what comes next,” Nabi said.

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