SpaceX delays commercial space station flight to allow more time for pre-launch data review
SpaceX called off launch of its third commercial crew flight to the International Space Station Wednesday to allow more time for pre-flight data reviews. The flight, chartered by Houston-based Axiom Space, was reset for Thursday pending final analysis.
The delay was announced as the flight's four-man crew — retired astronaut Michael López-Alegría, Italian Walter Villadei, Swedish flier Marcus Wandt and Turkey's Alper Gezeravci — were getting prepared for launch on a two-week research mission aboard the orbital outpost.
Liftoff from the Kennedy Space Center's historic pad 39A was re-targeted for 4:49 p.m. EST Thursday, roughly the moment Earth's rotation carries the rocket into the plane of the station's orbit to enable a rendezvous.
During a teleconference Tuesday night, Benji Reed, SpaceX senior director of human spaceflight programs, mentioned two recent issues that engineers were reviewing: concern about Crew Dragon parachute "energy modulator" straps and the torquing of connectors holding the Crew Dragon to the Falcon 9's upper stage.
Reed said an inspection of an unpiloted Cargo Dragon that recently returned to Earth from the space station revealed some of the folded, stitched-together straps holding the ship's main parachutes in place during flight had not performed quite as expected.
The folded straps are designed to pull apart, unstitching in a controlled fashion as the parachutes deploy, easing the shock of inflation. Some of the straps on the Cargo Dragon's parachutes came unstitched in a way that slightly increased those loads, although not enough to cause any problems.
Engineers concluded the suspect straps had a tendency to twist during installation, which may have contributed to the unstitching phenomenon. As a result, the parachutes in the Crew Dragon awaiting launch were inspected and adjusted to ensure no such twists are present.
As for the connectors holding the Crew Dragon to the Falcon 9, Reed said some had been torqued, or tightened, to slightly different levels than those specified. Out of "an abundance of caution," the connectors were replaced.
"We'll be completing our launch readiness review tomorrow (Wednesday) morning, and that will give us an opportunity to review all of the data and finalize everything for the flight," he said. "Flying the crew safely is always our top priority, and we will only launch when we're ready."