Boeing’s CST-100 Starliner descends under parachutes, its landing airbags inflated, just before landing at White Sands Space Harbor in New Mexico on May 25. (credit: NASA/Bill Ingalls) |
by Jeff Foust
Tuesday, May 31, 2022
At a press conference hours after Boeing’s CST-100 Starliner landed in the New Mexico desert on Wednesday, a reporter asked Mark Nappi, Boeing’s commercial crew program manager, to rate the just completed Orbital Flight Test (OFT) 2 mission on a scale of one to ten.
“On a scale of 1-10 I think I would give it 15. It was amazing,” he replied.
| “It’s great to have this amazing test flight behind us,” said Stich. “The test flight was extremely successful. We have achieved all mission objectives. |
This assessment may have been hyperbolic – Spinal Tap, after all, only went to 11 – but it was understandable. Nearly two and a half years after OFT’s original mission failed to achieve its objectives, and more than nine months after OFT-2’s first launch attempt was canceled due to corroded valves in the spacecraft’s service module, Starliner had traveled to the International Space Station and back, largely successfully.
After docking with the ISS a day after its May 19 launch (see “For Starliner, better late than never”The Space Review, May 23, 2022), NASA and Boeing completed work on the spacecraft on May 24. This included checking communications and other systems on the spacecraft, while transferring over 200 kilograms of cargo from spacecraft to station and nearly 300 kilograms from station to spacecraft for return to Earth.
The final phases of the mission went well, with the Starliner undocking from the station at 2:36 p.m. EDT Wednesday. He moved away from the station, performed a deorbit and jettisoned his service module. The spacecraft deployed its narcotics and main parachutes as planned, landing at White Sands Space Harbor at 6:49 p.m. EDT.
NASA Commercial Crew Program Manager Steve Stich called the landing “perfect” during the briefing. The capsule landed less than 500 meters from the intended location, a deviation which he said was due to different winds than expected.
“It’s great to have this amazing test flight behind us,” he said. “The test flight was extremely successful. We have achieved all mission objectives.
Although successful, the flight was not perfect. Two of the 12 Orbital Maneuvering and Attitude Control (OMAC) thrusters, both in the same pod or “niche” on the Service Module, shut down during orbital insertion just after the May 19 launch. Stich said controllers tested them after undocking but were unable to retrieve them. “We saw an interesting signature that looks a bit like the signatures we saw when stationary: maybe 25% or so of the thrust we expected from these thrusters.”
Nappi said this test can help better understand the root cause of OMAC thruster failures. “That isolates it more from the thrusters themselves than from any other part of the system,” he said.
Stich said the fact that the thrusters fired showed that commands were reaching the thrusters to open the valves and ignite. “We’ll have to look at the legs of the fault tree where we were pushed, but it wasn’t quite the level we expected,” he said.
He said controllers were able to restore two reaction control system thrusters that failed after launch, but added that one of those thrusters on the crew capsule could have shut down just before the launches were deployed. parachutes. This may be easier to investigate than OMAC thruster failures since that thruster can be inspected, while the OMAC thrusters were on the jettisoned service module.
A SpaceX Crew Dragon spacecraft, docked to the ISS, is in the foreground as Starliner pulls away from the station after undocking. (credit: NASA) |
Despite the propellant issues, NASA and Boeing seemed optimistic about their ability to move on to the Crew Flight Test (CFT) mission, where Starliner will carry astronauts for the first time. “I don’t see any reason why we can’t do the crew flight test afterwards,” Stich said. “I don’t really see any obstacles this time compared to last time.”
He said OFT-2 compared favorably to Demo-1, SpaceX’s Crew Dragon uncrewed test flight in March 2019. “The performance was very similar in many ways,” he said. , adding that SpaceX needs to upgrade its abort thrusters between Demo -1 and Demo-2 crewed missions, as well as work on the parachutes. “I don’t see that here from what we saw on this flight.”
It remains to be seen exactly when CFT will be launched and who will be on board. Nappi said during the briefing that the company was preparing the other Starliner crew capsule, called Spacecraft 3 or Calypso, for CFT. This spacecraft previously flew OFT, while the capsule that returned from OFT-2, called Spacecraft 2, will be prepared for the first operational mission, Starliner-1. (Spaceship 1 was used for a pad abort test and will not fly in space.)
“We’re working on that right now,” he said. This work will depend on what changes Boeing needs to make to the spacecraft based on lessons from OFT-2. Additionally, Boeing will need to negotiate with NASA to find a time when the ISS can accommodate the mission given the schedule of other visiting vehicles. The company will also need an Atlas 5 from United Launch Alliance.
“All of that needs to come together to set a flight date, and we’re probably several months away from being able to do that,” he said.
Another issue is who will drive the CFT. When NASA made the initial crew assignment for the mission in August 2018, agency astronauts Eric Boe and Nicole Mann, along with Boeing commercial astronaut (and retired NASA) Chris Ferguson were to fly. In 2019, Mike Fincke replaced Boe for medical reasons. In 2020, Ferguson announced that he would not fly the CFT, then scheduled for 2021, to avoid conflicts with family events. NASA replaced him with astronaut Butch Wilmore.
Last October, NASA reassigned Mann and Josh Cassada from Starliner-1 to SpaceX’s Crew-5 mission. During a pre-launch briefing for OFT-2 earlier this month, Wilmore, Fincke and Suni Williams, a NASA astronaut who had also been assigned to Starliner-1, said they were training now together as an “executive” to fly CFT or Starliner-1. Starliner-1 and is not part of that framework, agency officials said later.)
Wilmore said the postponement of OFT-2 in August, along with the reassignments of Mann and Cassada, led to the change. “As of this August, the three of us have been working as executives to support Starliner, and we know that we are not necessarily assigned to the CFT.”
| “It was truly a fantastic test flight, and it puts us in a great position to fly CFT,” said Nappi. |
Kathy Lueders, NASA associate administrator for space operations, said during this pre-launch briefing that crew assignments for the CFT would likely take place this summer, after determining the schedule for other missions to the station and the duration of the CFT. NASA once envisioned CFT spending up to six months on the station, using it as a crew rotation mission when access to Soyuz seats seemed uncertain, but that’s no longer necessary because SpaceX’s Crew Dragon now handles routine crew missions.
“You realize the challenge the crew office has about assignments and why it’s important to get the timing right and understand exactly when the crew flight test is going to show up,” he said. she declared during this briefing. She added that there were no plans for Ferguson or another Boeing commercial astronaut to join the CFT mission.
If the CFT is only needed as a test flight, the mission will probably last no more than two weeks, and possibly as little as five to seven days, just enough to confirm that the vehicle can carry people safely. Joel Montalbano, NASA’s ISS program manager, said the station’s program would make the most of even a limited CFT stay. “Once we define the objectives for the CFT mission, we will make maximum use of the crew’s time and add science as needed,” he said.
Stich said he felt “ecstatic” about OFT-2, especially seeing Starliner docked with the ISS at the same time as Crew Dragon. “That’s what the commercial crew program has always been, having these two different companies, with the great systems they’ve developed, proves the transportation of the crew to the space station,” he said. declared. “The flight that just landed today demonstrates that the Starliner is an excellent vehicle for crew transport.”
“We couldn’t have asked for a better mission,” Nappi said after rating OFT-2 a 15 on a scale of 1 to 10. “It was truly a fantastic test flight, and that puts us in an excellent position to pilot CFT.”
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