SpaceX calls off Crew-10 astronaut launch for NASA due to hydraulics issue (video)

SpaceX won't launch its next astronaut mission for NASA today (March 12) after all.

The company had planned to send the four-person Crew-10 mission toward the International Space Station (ISS) atop a Falcon 9 rocket from Kennedy Space Center in Florida this evening at 7:48 p.m. EDT (2348 GMT). About 45 minutes before liftoff, however, SpaceX called the attempt off due to a hydraulics issue with the transporter-erector, the structure that hauls the Falcon 9 to the pad and supports it once it's there.

"Great working with you today," Crew-10 commander Anne McClain of NASA told launch controllers after the scrub. "Kudos from the whole team, I know it was a lot of work to try to go, but like I said earlier, we'll be ready when the equipment is."

The problem involved a clamp arm on the transporter-erector, NASA officials said during the agency's launch webcast today. There were no issues with Crew-10's Falcon 9 or its Crew Dragon capsule, named Endurance.

"This is a concern of basically just how the vehicle is held in place during release at liftoff," said Mike Ravenscroft, launch vehicle office manager with NASA's Commercial Crew Program.

It wasn't immediately clear when SpaceX would try again to launch Crew-10. There are opportunities on both Thursday (March 13) and Friday (March 14), but SpaceX is still assessing the hydraulics issue and its possible fixes, NASA officials said.

Related: Meet the astronauts of the SpaceX Crew-10 mission

The Crew-10 astronauts are McClain and pilot Nichole Ayers (both of NASA), JAXA (Japan Aerospace Exploration Agency) astronaut Takuya Onishi and Kirill Peskov of Russia's space agency Roscosmos.

The quartet will head to the International Space Station for a roughly six-month stay. They'll relieve four other astronauts — NASA's Nick Hague, Suni Williams and Butch Wilmore and cosmonaut Aleksandr Gorbunov, who will come back to Earth a few days after Crew-10 docks.

Williams and Wilmore arrived at the ISS in early June on the first crewed flight of Boeing's Starliner capsule. Their mission was supposed to last just 10 days or so, but problems with Starliner's thruster system extended their stay repeatedly. NASA ultimately decided to bring Starliner home uncrewed and put Williams and Wilmore on SpaceX's Crew-9 capsule for the ride home.

That capsule, named Freedom, reached the ISS in late September with Hague and Gorbunov aboard. NASA took two other astronauts off the Crew-9 launch to open up seats for Williams and Wilmore on the journey back to Earth.