NASA and Boeing have announced they will not be attempting to launch the CST-100 Starliner spacecraft to the International Space Station on Wednesday, August 4.
The announcement came hours after it scrubbed a launch set for 1:20 p.m. (ET) on Tuesday, August 3. The cause was a valve issue discovered in a propulsion pump inside Starliner’s service module.
The crucial test mission, when it gets underway, will be the second flight for Starliner following a failed effort in December 2019.
When Tuesday’s uncrewed launch was abandoned, Wednesday remained in the launch window and therefore offered the next opportunity for lift-off. But having spent the afternoon assessing the situation, NASA and Boeing decided more time is needed to investigate the issue.
“Following today’s scrubbed launch of the CST-100 Starliner spacecraft, Boeing is working to understand the source of the unexpected valve position indications in the propulsion system,” the aerospace giant said in a statement released on Tuesday evening. It said the problem was first detected during routine checks made after electrical storms passed over the launch site at Kennedy Space Center in Florida on Monday.
Boeing added that it’s been able to rule out a number of potential causes, “including software,” a notable remark as it was a number of software issues that caused Starliner’s maiden mission to fail at the end of 2019.
“We’re going to let the data lead our work,” John Vollmer, vice president and program manager of Boeing’s Commercial Crew Program, said in a release. “Our team has worked diligently to ensure the safety and success of this mission, and we will not launch until our vehicle is performing nominally and our teams are confident it is ready to fly.”
After switching off the spacecraft’s power systems, ULA’s Atlas V rocket, which will carry Starliner to orbit, will be rolled back to a sheltered facility on Wednesday for further inspection and testing so NASA and Boeing can plan the next steps.
The decision to scrub Tuesday’s launch and also to stand down from a launch attempt on Wednesday will be a big disappointment not only for the teams behind the mission, but also for the many space fans who were eager to see the revamped spacecraft make it safely to the space station ahead of its first crewed flight.
But with so much at stake following the failed mission more than 18 months ago, it’s certain that the tiniest of anomalies spotted prior to launch will keep the spacecraft grounded.
No new launch window has yet been announced, but we’ll update here when we know more.
