NASA and SpaceX were faced with a last-minute issue during the Falcon 9 launch of a commercial crew mission on February 27, causing a delay in the lift-off.

The launch was scheduled for 1:45 a.m. Eastern, but it was put on hold due to a problem with the ignition system that uses a chemical combination of Triethylaluminum Triethylborane (TEA-TEB).The launch director informed the four-person crew of the Crew Dragon of the issue a few minutes before the scheduled lift-off. According to a statement released by NASA two hours after the scrub, the launch was halted “to investigate an issue preventing data from confirming a full load” of TEA-TEB. SpaceX later confirmed in a tweet that it was a ground system issue.

In a show of appreciation for the safety measures, Bill Nelson, the NASA Administrator, commended the teams, saying, “I’m proud of the NASA and SpaceX teams’ focus and dedication to keeping Crew-6 safe. Human spaceflight is an inherently risky endeavor, and as always, we will fly when we are ready.”

This was the first time a technical issue caused a scrub in a SpaceX human spaceflight launch. Crew-6 is the ninth mission for SpaceX, following the Demo-2 test flight, five International Space Station crew rotation missions, and the Inspiration4 and Ax-1 private astronaut missions.

While NASA and SpaceX had a backup launch opportunity on February 28, they did not attempt a launch due to poor weather conditions. Mike McAleenan, the launch weather officer for the U.S. Space Force 45th Weather Squadron, said that although conditions at the launch site would remain good, there would be high winds and wave conditions along the ascent corridor up the East Coast.

Steve Stich, the NASA commercial crew program manager, stated that “The weather is not looking good at all for that particular opportunity,” during a pre-launch briefing on February 25. NASA previously stated that it would skip a March 1 launch because of an unfavorable trajectory.

The next three opportunities to launch Crew-6 start on March 2, with NASA choosing 12:34 a.m. Eastern on March 2 as the next launch attempt, pending resolution of the TEA-TEB issue. During the briefing, Stich commented that it was too early to predict the weather conditions for the upcoming March launch attempts.

In an interview, Stich said, “The teams are continuing to work the technical issue and we’re in a good position to fly the next opportunity on March 2.”

Stich added that the Crew-6 mission would transport NASA astronauts Stephen Bowen and Warren Hoburg, along with Roscosmos mission specialist Andrey Fedyaev and Emirati astronaut Sultan Alneyadi to the International Space Station. Bowen and Hoburg would have served as mission commander and pilot, respectively, during their approximately six-month stay on the ISS.

Although the Crew-6 launch was cancelled and will be rescheduled for a later date, the delay will not have any impact on the two other scheduled SpaceX Falcon 9 launches on February 27. The first Falcon 9 will launch from Cape Canaveral Space Force Station in Florida at 1:38 p.m. Eastern, carrying 21 “V2 Mini” Starlink satellites. These larger spacecraft have four times the capacity of previous Starlink satellites and will be placed in orbits authorized by the Federal Communications Commission for its Gen2 system. The second Falcon 9 will launch from Vandenberg Space Force Base in California at 2:31 p.m. Eastern, carrying 51 first-generation Starlink satellites.