Crew-1 astronauts in Crew Dragon
NASA astronauts (from left) Shannon Walker, Victor Glover and Mike Hopkins, and JAXA astronaut Soichi Noguchi sit in a Crew Dragon capsule during training for their Crew-1 mission, now scheduled to launch Oct. 23. Credit: SpaceX

WASHINGTON — NASA is delaying the launch of an ocean science satellite on one Falcon 9 rocket, but says that delay will not affect another Falcon 9 launch of a commercial crew mission.

The agency announced Nov. 3 it was delaying the launch of the Sentinel-6 Michael Freilich satellite on a Falcon 9 from Vandenberg Air Force Base in California from Nov. 10 to Nov. 21. The reason for the delay, the agency said, was to give SpaceX time to replace two engines in the rocket’s first stage.

The performance of the Falcon 9’s Merlin engines had been under scrutiny since a launch abort seconds before the scheduled liftoff of a Falcon 9 carrying a GPS 3 satellite Oct. 2. An investigation eventually blamed the abort on a “masking lacquer,” a coating used to protect engine components when they are anodized for corrosion protection. The lacquer was not properly cleaned after anodizing, blocking a relief valve in the gas generator of one of the Merlin engines in the stage.

At an Oct. 28 briefing, NASA said it was replacing two Merlin engines in the Falcon 9 booster that will launch the Crew-1 commercial crew mission, currently scheduled for Nov. 14 from the Kennedy Space Center. At the time it said it was replacing one engine on the Falcon 9 first stage for Sentinel-6 Michael Freilich, but that it was still inspecting the engines on that booster.

Before the briefing, NASA indicated that the Sentinel-6 launch would take place first, and that NASA would review the data from the launch before deciding to proceed with the Crew-1 mission. But at that briefing, agency officials said Crew-1 didn’t need to wait for the Sentinel-6 launch. “There is, right now, not a hard bar between these missions,” said Kathy Lueders, NASA associate administrator for human exploration and operations. “We’re going to fly both missions when it’s the right time.”

Instead, agency officials said they wanted to see the GPS 3 launch go first. “One of the engines that we are installing on the first stage has a slight change that we would like to see fly on the GPS 3 mission first,” said Steve Stich, manager of NASA’s commercial crew program. “We would like to see that one mission go fly before we fly crew.”

At the time of the briefing, SpaceX had not yet rescheduled the GPS 3 launch. However, after a successful static-fire test of the booster Oct. 31, SpaceX announced that the launch was now rescheduled for Nov. 5.

NASA, in the statement about the Sentinel-6 launch delay, stated that the Crew-1 mission remains on schedule for Nov. 14. The four-person crew entered prelaunch quarantine Oct. 31, and will travel to the Kennedy Space Center for final prelaunch preparations Nov. 8.

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...