ORLANDO — NASA has delayed the launch of a commercial crew mission to the International Space Station by a day to give SpaceX additional time to complete work on the vehicle.

At a briefing after a flight readiness review for the Crew-6 mission Feb. 21, NASA announced it has rescheduled the launch of the Crew Dragon spacecraft to Feb. 27 at 1:45 a.m. Eastern. The Falcon 9 launch of the spacecraft had been planned for Feb. 26.

Steve Stich, NASA commercial crew program manager, said the agency and SpaceX were “a little bit behind” on the work needed to prepare the mission for launch. That included additional thermal analysis of panels on the exterior of Dragon and testing of composite overwrapped pressure vessels in the Falcon 9.

He added NASA was also analyzing data from all Falcon 9 launches, citing a Starlink mission earlier in the month where there was “a little bit of evidence of combustion” in an engine bay on the booster. That booster was on its twelfth mission, while the Falcon 9 booster flying Crew-6 will be making its first launch.

“We’ve still got a little bit of work, as Steve described, to go ahead and take a look at some of the hardware that came back,” said Bill Gerstenmaier, SpaceX vice president of build and flight reliability. “I don’t think those things are going to be a concern for the crewed flight but we don’t take things for granted. We want to make sure they’re really ready.”

If the launch slips again, there is another launch opportunity Feb. 28 at 1:22 a.m. Eastern, followed by three opportunities March 2 through 4. Stich said it was still too early to forecast weather for the launch but cautioned there may be “some challenges” with weather conditions at abort landing sites along the East Coast.

Crew-6 will deliver NASA astronauts Stephen Bowen and Warren Hoburg, who will be commander and pilot, respectively, of the mission. Also on Crew-6 are Russian cosmonaut Andrey Fedyaev and Emirati astronaut Sultan Alneyadi. The four will stay on the station for about six months, while the crew of the Crew-5 mission that has been on the station since October — Nicole Mann, Josh Cassada, Koichi Wakata and Anna Kikina — will return to Earth about five days after the Crew-6 arrival.

An image of a hole 12 millimeters across on the Progress MS-21 spacecraft that Roscosmos believes is the source of the coolant leak. Credit: Roscosmos

Progress investigation continues

The Crew-6 mission is not affected by the ongoing investigation into a coolant leak suffered Feb. 11 by the Progress MS-21 spacecraft that was docked to the station at the time. The spacecraft undocked from the station as planned Feb. 17 and reentered a day later.

Roscosmos announced Feb. 21 that imagery of the Progress taken during its departure from the station showed a hole 12 millimeters in diameter in the spacecraft’s radiator, from which coolant leaked. In a statement posted on the agency’s Telegram social media account, it blamed the hole on “external influences” that it said were similar the leak experienced by the Soyuz MS-22 spacecraft in December. Roscosmos earlier blamed the Soyuz leak on a micrometeoroid impact.

At the Crew-6 briefing, Dana Weigel, NASA ISS deputy program manager, said NASA was studying the Progress images in parallel with Roscosmos. “The Russians are continuing to take a very close look at both the Soyuz and the Progress coolant leaks,” she said, forming a commission to analyze the incidents. “They’re looking at everything from ground, launch through on orbit in terms of causal factors to try to understand that.”

She said NASA had not talked with Roscosmos about their initial assessment of the Progress damage, but noted that “external influences” did not necessarily mean a micrometeoroid or orbital debris impact.

“I think what they’re really trying to understand is, are there any signs or signatures that somewhere along the spacecraft’s journey, whether it’s launch or launch vehicle separation, there is some other external influence or damage that could have occurred that could have been a factor there,” she said, adding that NASA had not seen any indication of an increase in the micrometeoroid environment at the station.

NASA’s own review of the imagery was focused on identifying the location of the coolant leak, Weigel explained. The coolant, which she described as being very viscous, was still clinging to the vehicle as a “shadowed and glossy area” in those images, as well as a darker area NASA interpreted as the hole the coolant leaked from.

Gerstenmaier said that NASA, as a precaution, performed an inspection of the exterior of the Crew-5 Crew Dragon docked to the station and found no evidence of damage from micrometeoroids or orbital debris. “That used to be a nice to have,” he said of the inspection. “We’ve now made it an official flight rule, so it will get done every time.” He added Crew Dragon has two separate radiator loops, providing redundancy if one is damaged.

Roscosmos is moving ahead with plans to launch the Soyuz MS-23 spacecraft on an uncrewed mission to the ISS to replace the damaged Soyuz MS-22. Its launch on a Soyuz-2.1a rocket is scheduled for Feb. 23 at 7:24 p.m Eastern. It will dock with the station two days later.

Weigel said that Roscosmos has inspected the Soyuz MS-23 spacecraft “and they’re not seeing any issues with the vehicle so they’re pressing ahead with their launch preparations.”

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...