WASHINGTON — NASA and Boeing have reset the launch of the company’s CST-100 Starliner spacecraft on June 5 after United Launch Alliance fixed a computer problem that led to the cancellation of the previous launch attempt.
NASA announced late June 2 that mission managers have given their approval to proceed with the launch of the Crew Flight Test (CFT) mission on June 5 at 10:52 a.m. ET, the next available launch opportunity. The backup opportunity is June 6 at 10:29 AM ET.
The previous CFT launch attempt on June 1 was aborted 3 minutes and 50 seconds before the scheduled liftoff. ULA said that a card known as a launch sequencer in one of the three redundant ground control computers appeared slower than the other two when exiting a pre-planned hold at T-4 minutes. ULA CEO Torey Bruno speculated that a hardware or networking issue might explain what happened.
NASA said in a statement that ULA found a problem with the power supply unit used by part of the cards in one computer. This includes the card controlling the valves used to replenish propellant in the Centaur upper stage, which also malfunctioned earlier in the countdown.
NASA said ULA decided to replace the computer rack or chassis with the faulty power unit with a spare while technicians investigated the cause of the power supply failure. “ULA has completed functional inspections of the new structure and cards, and all instruments are operating normally,” NASA reported.
The weather is again expected to be suitable for the launch, with a 90% chance of acceptable launch conditions on June 5. NASA has not reported any other problems in the works with the Atlas 5 rocket and its ground support equipment, or with the Starliner spacecraft itself. .
On the CFT mission, Starliner, with NASA astronauts Butch Wilmore and Sonny Williams on board, will fly to the International Space Station, where it will spend about a week there before returning to land in the southwestern United States. The mission is the last test flight before NASA can certify the vehicle for operational missions to the International Space Station starting in early 2025.
NASA and ULA said that if Starliner doesn’t launch by June 6, they will step aside in order to do work on the rocket itself, replacing expired batteries. They said it will take about 10 days to complete this work.
