SpaceX is replacing two engines on the rocket that will launch the company's next crewed mission, which is scheduled to lift off on Nov. 14.
The measure follows an investigation into the aberrant behavior of the SpaceX Falcon 9 rocket that was supposed to launch a GPS satellite for the U.S. Space Force on Oct. 2. That liftoff was aborted automatically with just two seconds left on the countdown clock when sensors picked up off-nominal readings.
The upcoming astronaut launch, which will kick off SpaceX's Crew-1 mission to the International Space Station for NASA, also will employ a Falcon 9. So NASA and SpaceX pushed back Crew-1's target liftoff date, which had been Oct. 31, to allow time for an investigation and make sure the same problem won't affect the astronaut launch.
The investigation of the Oct. 2 abort traced the issue to two of the nine Merlin engines on the Falcon 9's first stage. Those two Merlins retained residue of a "masking lacquer" designed to protect sensitive parts during anti-corrosion anodizing treatment, Hans Koenigsmann, SpaceX's vice president of build and flight reliability, said during a news conference on Wednesday (Oct. 28).
The vendor performing the treatment didn't manage to remove all of the lacquer afterward, and some of it ended up blocking 0.06-inch-wide (1.6 millimeters) vent holes for valves in two of the Merlins that were supposed to power the two-stage Falcon 9 skyward on Oct. 2, Koenigsmann said.
After analyzing a wide range of Merlin data, SpaceX found signs of a similar issue with two of the engines in the Crew-1 Falcon 9's first stage, as well as one Merlin in the first stage of the booster scheduled to loft the Sentinel-6 Michael Freilich Earth-observing satellite for NASA and several of its partners on Nov. 10.
So SpaceX is now swapping out all of those affected Merlins for ones known to be free of masking-lacquer residue, Koenigsmann said.
The investigation and troubleshooting process, which SpaceX conducted with the help of NASA and the Space Force, "led to a really good review and a really good anomaly resolution that, in my opinion, makes a better vehicle and a better engine going forward," Koenigsmann said.
SpaceX's safety systems worked properly on Oct. 2, noticing the anomaly in time and aborting the launch, he said. And a liftoff that day may not have been disastrous, Koenigsmann added; the Falcon 9 might have experienced a "hard start" caused by introducing various fluids — igniter fluid, liquid oxygen and kerosene — in the wrong order in the affected engines.
"It's not necessarily bad," he said of a hard start. "In most cases, it rattles the engine, and it may cause a little bit of damage to the engine. In extreme cases, it may cause more damage to the engine."
Still on track
The Falcon 9 should be ready in time for the planned Nov. 14 launch of Crew-1, NASA officials said during Wednesday's news conference, though they stressed that the mission will launch when it's ready and not be constrained by an arbitrary timeline.
And NASA wants to see another Falcon 9 fly before the astronaut launch — specifically, the one that will loft the GPS satellite that was supposed to go up on Oct. 2 (and which also got a two-Merlin swap), said Steve Stich, manager of NASA's Commercial Crew Program. The GPS launch, which will take place from Florida's Cape Canaveral Air Force Base, is currently targeted for no earlier than Nov. 4, according to Spaceflight Now.
Processing of the SpaceX Crew Dragon capsule that will carry the four Crew-1 astronauts — NASA's Shannon Walker, Victor Glover and Michael Hopkins and Japan's Soichi Noguchi — to the space station for a 6-month stay is coming along nicely, Stich said.
If all goes according to plan, NASA and SpaceX will conduct a flight readiness review for Crew-1 on Friday (Oct. 30) and start loading propellant this weekend into the Crew Dragon, which its riders have named "Resilience," Stich said.
The four astronauts are currently in "soft quarantine" at their homes and will enter a more stringent quarantine on Halloween, Stich added. The quartet will travel to the Crew-1 launch site, NASA's Kennedy Space Center in Florida, on Nov. 6, if all goes according to plan.
Crew-1 will be SpaceX's second astronaut mission to the International Space Station for NASA. On May 30, Elon Musk's company launched Demo-2, a test flight that carried NASA astronauts Bob Behnken and Doug Hurley to the space station for a two-month stay. A review of the Demo-2 data has been completed, clearing the path for Crew-1, Stich said.
SpaceX holds a $2.6 billion contract with NASA to fly at least six operational missions, the first of which will be Crew-1, to and from the station. Boeing signed a similar deal, worth $4.2 billion, which it will fulfill using a capsule called CST-100 Starliner. Starliner isn't ready to carry astronauts yet, however; the capsule still must refly an uncrewed test flight to the station, after failing to meet up with the orbiting lab as planned during its first attempt in December 2019.
Mike Wall is the author of "Out There" (Grand Central Publishing, 2018; illustrated by Karl Tate), a book about the search for alien life. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or Facebook.