NASA has announced that it is considering the return of the CST-100 Starliner crew on the Crew Dragon spacecraft. The organization also confirmed that it would move the launch date of the Crew-9 mission from August 18 to September 24.
The Starliner was launched on June 5. Astronauts Butch Wilmore and Sunita Williams were on board. The main purpose of their mission was a comprehensive test of all systems of the spacecraft in real flight conditions.
During docking with the ISS, the spacecraft failed several engines of the orientation system. Most of them were later restored to operation, but this raised questions about the safety of using Starliner to return to Earth. Therefore, ground tests of the engines were conducted at White Sands Test Facility, as well as several brief launches in space.
It was originally expected that the decision on whether to return the Starliner with or without a crew would be made as early as the end of July. However, it had to be postponed due to lack of consensus within NASA. Boeing representatives claimed that the spacecraft was all right and could return to Earth at any time. The lack of official information created a whole wave of rumors, eventually forcing NASA to organize a briefing.
Back on Crew Dragon
At the August 7 briefing, it was stated that a decision on the Starliner would be made in mid-August. If NASA thinks Butch Wilmore and Sunita Williams’ return is too risky, they will stay on the ISS until February 2025. In this case, the astronauts will return to Earth on the Crew Dragon spacecraft along with members of the Crew-9 expedition. Initially, its launch was scheduled for August 18. But NASA confirmed rumors circulating earlier that it would be moved to September 24. If the decision is made to use this option, the Crew-9 members would be minimized from four to two astronauts.
It has also been confirmed that the current Starliner software is not capable of automatically undocking the spacecraft from the ISS and will need to be updated. This is a long process that will take at least several weeks.
Starliner engine problems
NASA also touched on the results of ground tests of the Starliner propulsion system at White Sands Test Facility. They had to provide confidence that the engines would perform as required during the re-emergence phase. But it turned out to be exactly the opposite. The tests demonstrated that heating of the engines can cause the Teflon seal to extrude, restricting the flow of rocket fuel. Heating the fuel can also cause it to vaporize, reducing performance.
According to NASA specialists, they are concerned about the emergence of the so-called integrated failure mechanism, when problems with the engines and helium leaks will create difficulties in maintaining the orientation of the spacecraft during the descent from orbit. In this situation, the realization of a “Plan B” to return the Starliner crew on Crew Dragon looks like an increasingly realistic prospect.
According to Spacenews
