The inaugural crewed flight test of Boeing’s CST-100 Starliner, a reusable capsule designed to ferry astronauts to and from the International Space Station (ISS), will launch no earlier than May 17, NASA said Tuesday.
Initially scheduled for early 2023, the flight, called Boeing Crewed Flight Test-1 (CFT-1), has since been delayed multiple times. The most recent setback occurred before a planned launch on Monday, which was called off just two hours before takeoff due to a valve issue on the upper stage of the United Launch Alliance (ULA) Atlas V launch vehicle that will send Starliner into orbit. ULA is a joint venture between Boeing and Lockheed Martin.
ULA crews identified the issue after noticing a buzzing noise created by an oscillating pressure regulation valve located on a liquid oxygen tank on the Atlas V’s upper stage. Starliner astronauts Butch Wilmore and Suni Williams safely exited the spacecraft, which was parked at Space Launch Complex-41 at Cape Canaveral Space Force Station in Florida.
Teams were quickly able to repair the oscillating valve. But according to NASA, the issue resurfaced twice during fuel removal. After evaluating the valve and completing a thorough review on Tuesday, ULA decided to remove and replace it.
As a result, NASA announced that the next launch attempt will take place no earlier than 6:16 p.m. EDT on Friday, May 17.
ULA on Wednesday rolled Atlas V and Starliner, still stacked together, back to NASA’s Vertical Integration Facility at Space Launch Complex-41. There, teams are working to replace the faulty part and perform leak checks and functional checkouts before the next launch attempt.
The Starliner program has contended with nearly a decade of delays since Boeing first announced it in 2011, including an uncrewed orbital test flight that failed to reach the ISS as planned.
CFT-1 is expected to be the spacecraft’s final flight before being deployed for NASA’s Commercial Crew program, which rotates astronaut crews at the orbital laboratory.
All eight Commercial Crew rotation missions to date have been flown using SpaceX’s Crew Dragon capsule, an alternative to Starliner also under contract with NASA. Boeing and NASA’s contract includes a total of six service missions using Starliner.
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