NASA and Boeing prepare for the second Starliner test flight

KENNEDY SPACE CENTER, Fla. — Boeing’s CST-100 Starliner spacecraft is set to attempt another uncrewed test flight to the International Space Station, and both the company and the agency have expressed confidence in the spacecraft despite the past problems.

The Starliner spacecraft, atop a United Launch Alliance Atlas 5 rocket, rolled onto the pad at Space Launch Complex 41 in Cape Canaveral, Florida, on May 18. Launch of the spacecraft on the Orbital Flight Test (OFT) 2 mission remains scheduled for 6:54 pm ET May 19.

In pre-launch briefings here, NASA and Boeing officials said they weren’t dealing with any technical issues before launch, and weather forecasts project a 70% chance of acceptable launch conditions. A backup launch opportunity is available on May 20 at 6:32 pm ET, although weather forecasts project only a 30% chance of acceptable weather.

According to the mission plan, Starliner will dock with the station about 24 hours after liftoff. She will remain there for several days for tests before undocking and landing at White Sands Space Harbor in New Mexico. The mission will last 5 to 10 days, depending in part on weather conditions at the landing site.

This will be the second attempt to launch OFT-2. The initial launch in August 2021 was canceled hours before liftoff when propulsion valves in the spacecraft’s service module failed to open when ordered. Engineers discovered that the valves had corroded shut, causing an extended mission delay. NASA and Boeing later concluded that the nitrogen tetroxide propellant, seeping through the valve’s Teflon seal, reacted with ambient moisture to create nitric acid that corroded the valve’s aluminum elements.

This mission comes nearly two and a half years after the original OFT mission in December 2019. The spacecraft suffered problems immediately after separation from the rocket because a mission event timer on the spacecraft was not set correctly. Engineers also discovered a software problem that could have caused the spacecraft’s service module to collide with the crew module again after separation just before re-entry, fixing it with only a few hours to spare.

The OFT-2 mission will confirm that those problems have been fixed. Mark Nappi, Boeing’s vice president and commercial crew program manager, said at a May 17 briefing that spacecraft controllers have been regularly cycling the valves to make sure they don’t corrode. “Everyone traded nominally, so we’re in good shape,” he said.

The spacecraft will also carry out tests that the truncated OFT mission could not, in particular, approaching and docking with the ISS. “We’re going to pay attention to the machine vision system, called VESTA, which we didn’t get a chance to see in action in the first orbital flight test,” said Mike Fincke, a NASA astronaut who is among those training. for future Starliner missions, at a May 18 briefing. VESTA, or Vision-Based Electro-Optical Sensor Tracking Array, helps the spacecraft identify and approach the space station.

There will be tests once the Starliner docks with the station, including the work of space station astronauts Kjell Lindgren and Bob Hines. Fincke said they will be testing various Starliner systems, such as communications phones and microphones. “There are many things with the International Space Station interface that the space station crew will help us with.”

A successful OFT-2 mission would allow NASA to proceed with a test flight with astronauts on board, called the Crew Flight Test (CFT). That could launch as early as the end of the year, though agency officials were reluctant in pre-launch briefings to set a timeline for CFT.

“We’re getting our crew flight test vehicle ready for the end of the year,” Kathy Lueders, NASA’s associate administrator for space operations, said on May 18. That schedule will depend on the two of them resolving any issues that arise on OFT-2 as well as the timing of other ISS missions.

“We need to make sure there’s nothing we need to fix or upgrade on the spacecraft that we plan to have ready by the end of the year, and then set the full schedule for everyone,” he said, adding. that the agency must know this summer both CFT’s schedule and who will fly it and how long the mission will last.

There may still be work to be done even after a successful OFT-2 mission. At a meeting of NASA’s Aerospace Safety Advisory Panel on May 12, panel member David West warned that Boeing’s work to certify Starliner’s parachutes was being delayed, but did not elaborate. He also said the panel was concerned that Boeing’s staffing levels on the program were “especially low,” particularly given the amount of work needed to prepare for the CFT mission after OFT-2.

Nappi said on May 17 that he believed the panel’s concerns were with certification for post-CFT operational or post-certification missions. “We have some tests planned this summer with NASA” on parachutes, he said. “The results of that will obviously lead to certification.”

Butch Wilmore, another NASA astronaut training for early Starliner missions, exuded confidence in the spacecraft despite past problems and the possibility of new problems, or “unknown unknowns,” on this mission. “We wouldn’t be here right now if we weren’t sure this was going to be a successful mission,” he said at a May 18 briefing alongside Fincke and Suni Williams, another NASA astronaut.

“We are ready,” he said. “This spaceship is ready. These teams are ready. Boeing is ready. Ula is ready. The mission operations people who will control the spacecraft in space are ready and we’re excited.”

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