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 31 May 2022
At a press conference a few hours after Boeing’s CST-100 Starliner landed in the New Mexico desert on Wednesday, a reporter asked Mark Nappi, the program manager of Boeing’s commercial crew, to review the just-completed Orbital Flight Test (OFT) 2 mission on a scale of one to ten.
“On a scale of 1 to 10, I think I’d give it a 15. This was incredible,” he replied.
|“It’s great to have this incredible test flight behind us,” Stich said. “The test flight was extremely successful. We have achieved all mission objectives.”|
That rating may have been hyperbolic – Spinal Tap only went to 11, after all – but it was understandable. Nearly two and a half years after the original OFT mission failed to achieve its goals, and more than nine months after the first attempt to launch OFT-2 was canceled due to corroded valves in the spacecraft’s service module, Starliner had launched the International Space Station. and back, largely successfully.
After docking to the ISS a day after launch on May 19 (see “For Starliner, better late than never”The Space Review, May 23, 2022), NASA and Boeing completed work on the spacecraft on May 24. That included checking the communications and other systems on the spacecraft as they moved more than 200 kilograms of cargo from the spacecraft to the station and nearly 300 kilograms from the station to the spacecraft for return to Earth.
The final stages of the mission went smoothly, with Starliner disconnecting from the station at 2:36 p.m. EDT Wednesday. It moved away from the station, performed a deorbit burn, and jettisoned its service module. The spacecraft deployed its pilot and main parachutes as scheduled, landing at 6:49 PM EDT in White Sands Space Harbor.
Steve Stich, NASA commercial crew program manager, called the landing “perfect” during that briefing. The capsule landed within 500 meters of the target site, an anomaly he said was due to winds that were different than predicted.
“It’s great to have this incredible 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 Maneuver and Attitude Control (OMAC) thrusters, both in the same pod or “dog house” on the service module, were disabled during the orbital insertion fire just after launch on May 19. Stich said controllers tested them after unplugging but couldn’t recover them. “We saw an interesting signature that’s a bit like the signatures we saw at shutdown: maybe 25% or so of the thrust we expected from those thrusters.”
Nappi said the test could help better understand the cause of the OMAC thruster failures. “This isolates it more from the thrusters themselves than any other part of the system,” he said.
Stich said the fact that the thrusters were firing showed that commandos reached the thrusters to open valves and ignite. “We’ll have to look at the legs of the fault tree where we got thrust, but it wasn’t quite the level we expected,” he said.
He said controllers were able to recover two response control system thrusters that failed after launch, but that added such thrust to the crew pod may have shut down just before the parachutes were deployed. That may be easier to investigate than the OMAC thruster failures, as that thruster can be inspected, while the OMAC thrusters were on the dropped service module.
A SpaceX Crew Dragon spacecraft docked to the ISS is in the foreground as Starliner moves away from the station after undocking. (credit: NASA)
Despite the thruster issues, both NASA and Boeing sounded optimistic they could move on to the Crew Flight Test (CFT) mission, where Starliner will carry astronauts for the first time. “I see no reason why we can’t move forward with the Crew Flight Test,” Stich said. “I don’t really see any showstoppers this time around compared to last time.”
He said OFT-2 compares favorably with Demo-1, the unmanned test flight of SpaceX’s Crew Dragon in March 2019. “Performance was very similar in many ways,” he said, adding that SpaceX had to upgrade its broken-down thrusters between Demo. -1 and the manned Demo-2 missions, as well as work on parachutes. “I don’t see that from what we saw on this flight.”
When exactly CFT will launch and who will be on board remains to be seen. Nappi said during the briefing that the company is preparing the other Starliner crew pod, called Spacecraft 3 or Calypso, for CFT. That spacecraft previously flew OFT, while the capsule returning from OFT-2, called Spacecraft 2, will be prepared for its first operational mission, Starliner-1. (Spacecraft 1 was used for a pad abort test and will not fly into space.)
“We’re working on that now,” he said. That work will depend on what changes Boeing needs to make to the spacecraft based on lessons learned from OFT-2. In addition, Boeing will have to negotiate with NASA to find a time when the ISS can accommodate the mission, given the schedule of other visiting vehicles. The company also needs an Atlas 5 from United Launch Alliance.
“That all has to come together to establish a flight date, and we’ll probably be able to do that for several months,” he said.
Another issue is who will fly with CFT. When NASA created the original crew assignment for the mission in August 2018, agency astronauts Eric Boe and Nicole Mann were to fly along with Boeing commercial astronaut (and retired NASA astronaut) Chris Ferguson. In 2019 Mike Fincke replaced Boe for medical reasons. In 2020, Ferguson announced that he would not be flying with CFT, then expected in 2021, to avoid conflict with family events. NASA replaced him with astronaut Butch Wilmore.
Last October, NASA reassigned Mann and Josh Cassada, who would go on Starliner-1, to SpaceX’s Crew-5 mission. At a prelaunch briefing for OFT-2 earlier this month, Wilmore, Fincke and Suni Williams, a NASA astronaut also assigned to Starliner-1, said they were now training together as a “framework” to fly CFT or Starliner. 1. (Jeanette Epps, the NASA astronaut who was bumped from a Soyuz mission to the ISS in 2018 for still mysterious reasons, remains assigned to Starliner-1 and is not part of that cadre, agency officials later said. .)
Wilmore said the postponement of OFT-2 in August, along with Mann and Cassada’s reassignments, led to the change. “Since that time in August, the three of us have been working as an executive supporting Starliner, and we know we’re not necessarily assigned to CFT.”
|“It was a really 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 that prelaunch briefing that crew assignments for CFT would likely come in the summer, after determining the schedule of other missions to the station and how long CFT would last. NASA once envisioned CFT staying on the station for as many as six months, using it as a crew rotation mission when access to Soyuz seats seemed precarious, but that’s no longer necessary as SpaceX’s Crew Dragon now handles routine crew missions.
“You realize the challenge the crew office has in relation to the assignments and why it’s important to get the timing right and understand when exactly the Crew Flight Test will come out,” she said during that briefing. She added that there are no plans to have Ferguson or any other Boeing commercial astronaut rejoin the CFT mission.
If CFT is only needed as a test flight, the mission would probably last no more than two weeks, and perhaps five to seven days, just enough to confirm the vehicle can safely carry people. Joel Montalbano, NASA ISS program manager, said the station program would make the most of even a limited stay by CFT. “Once we establish the objectives for the CFT mission, we will use all of the crew’s time and add science where necessary,” he said.
Stich said he was “ecstatic” about OFT-2, especially when he saw Starliner docking at the ISS at the same time as Crew Dragon. “That’s what the commercial crew program has been about all along, because these two different companies, with the great systems they’ve developed, prove the transport of the crew to the space station,” he said. “The flight that just landed today shows that the Starliner is a great vehicle for crew transport.”
“We couldn’t have asked for a better mission,” Nappi said after giving OFT-2 a score of 15 on a scale of 1 to 10. “It was a really fantastic test flight and it puts us in a great position to fly CFT.”
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