The decision leaves the Boeing spacecraft on track for a May 19 launch from Cape Canaveral Space Force Station’s Space Launch Complex 41 in Florida, assuming no weather or technical concerns occur.
A backup launch date is available on May 20 at 6:32 p.m. EDT (2232 GMT), which would still see a birthday event if the timeline is shifted. Stich added, however, that the greater importance is getting Starliner set to carry astronauts.
NASA officials framed the completion of OFT-2 as crucial to launching more crewed missions to the space station in the near future. The agency is seeking to expand the number of astronauts on board the ISS at a time to boost the science potential of the orbiting complex.
“The most important step right now is to go fly this orbital flight test,” Stich said.
NASA authorised Starliner to launch on Orbital Flight Test-2 (OFT-2), a critical uncrewed mission to the International Space Station, during a flight readiness review on Wednesday (May 11).
Should the mission lift off on time, an ISS docking would happen roughly a day later, on May 20. “It’s my birthday, so I’m really looking forward to a great birthday present here next week,” joked Steve Stich, NASA’s Commercial Crew Program manager, of the docking in a teleconference with reporters Wednesday shortly after the review’s conclusion.
Mark Nappi, vice-president and program manager of the Boeing Commercial Crew Program, said his company is “prepared and ready” to assist with NASA’s work; Starliner currently faces no major obstacles in its review items to get set for launch, docking and landing.
“The Boeing team is prepared and ready. The NASA-Boeing partnership is really strong. It’s a reflection of all the hard work that’s been done,” Nappi said during Wednesday’s call.
Starliner’s major task will be to do what the capsule failed to do on the original OFT mission in December 2019: meet up successfully with the ISS to demonstrate new technologies and, overall, showcase a readiness to fly crews to and from space. Many of these technologies are connected with a sensor that will be active throughout the rendezvous with the ISS, Emily Nelson, deputy chief flight director at NASA, said during the press conference.
“One of the most important — and really kind of the coolest — sensor that they’ve got on their spacecraft is called VESTA; it looks for the silhouette of the space station,” she said. VESTA, short for “Vision-based Electro-optical Sensor Tracking Assembly,” will be assessed for its ability to identify the space station and to dock at the correct (forward) port on the Harmony module.
“We’ll do a couple of demonstrations, once we get close in, where the spacecraft will stop,” Nelson said, emphasizing that the goal is to make sure the spacecraft will halt when commanded to do that. Once that capability is established, “then we’ll press into the final rendezvous and docking.” Initially Starliner was set for an OFT-2 launch in August 2021. But during normal preflight checks, engineers found that 13 of the 24 oxidizer valves in the capsule’s propulsion system, located in Starliner’s service module, were stuck.
While every human spaceflight program has its own unique issues and challenges, Stich said the Boeing valve problem brought to his mind a situation during the space shuttle program. During the launch of STS-129 on Nov. 14, 2008, flight controllers saw an abnormal hydrogen flow increase in one of the shuttle Endeavour’s main engines. Addressing this flow control issue, as the problem was later termed, took months; the issue was eventually traced to a cracked valve arising from the stresses of repeated use. The fix was complex and is now framed as a case study of collaborative problem-solving on NASA’s Academy of Program/Project & Engineering Leadership (APPEL) Knowledge Service.
Fixing the valve problem required multiple adjustments, involving sealing a potential problem point for moisture in the electrical connectors, purging moisture using nitrogen gas and adding a new “cycling” routine every two to five days to keep the valves running smoothly. Boeing also replaced Starliner’s service module to get ready for the coming flight. Diagnosing the problem required rolling Starliner and its United Launch Alliance Atlas V rocket off the pad. A few months later, investigators located the probable cause of the valve issue, which came down to a chemistry issue. The nitrogen tetroxide oxidizer reacted with air moisture, creating nitric acid. Then the nitric acid reacted with the aluminum surrounding the valves, resulting in corrosion products creating difficulties with the valves’ function.