SpaceX Operational Astronaut Launch Back On Track After “Nail Polish” Delay

In a new NASA briefing, SpaceX Vice President of Flight Construction and Reliability Hans Koenigsmann was able to explain in much more detail why a recent last-second Falcon 9 launch abortion occurred and how delayed the company’s first operational astronaut launch.

Now scheduled to take off no earlier than (NET) 19:49 EST (00:49 UTC) on Saturday November 14, SpaceX’s Crew Dragon Crew-1 mission was originally scheduled to launch in late September, October 23, and October 31. On October 2, however, a new Falcon 9 booster, brother of the new crew booster-1, automatically stopped the launch attempt of the GPS III SV04 satellite just two seconds before takeoff. The rare last-second miscarriage was quickly attributed to “an unexpected increase in pressure in the turbomachinery gas generator” by CEO Elon Musk.

Probably built side by side with faulty GPS III SV04 Falcon 9 booster B1062 at the SpaceX factory in Hawthorne, California, the Booster Crew-1 Falcon 9 B1061 was almost immediately inspected for any commonalities once the cause of the abortion had been better understood.

Just a week before the last briefing, NASA human spaceflight program administrator and former commercial crew program manager Kathy Lueders revealed in a Twitter statement that SpaceX was still investigating the cause of the outage but had already established that at least one Crew-1 booster engine would need to be replaced, as well as an engine on the Falcon 9 booster B1063.

Now, during NASA’s Crew 1 briefing on October 28, SpaceX’s Koenigsmann has revealed that the company had decided to replace not one but two of the nine Merlin 1D engines from the Booster Crew-1 B1061. Thanks to the Falcon 9’s eponymous nine-engine booster project and SpaceX’s prolific rocket factory, that process was completed remarkably quickly, simply requiring the redirection of already qualified Merlin 1D engines from a large enough pool. Based on Koenigsmann’s phrasing, SpaceX has already installed both replacement engines on the Crew-1 booster.

What, however, caused the GPS III SV04 to stop launching and how did it affect Crew-1?

Rocket engine versus “nail polish”

According to Koenigsmann, in the course of the rapid and complex mechanical and electrical ballet that precedes the ignition of the first stage of the Falcon 9, the rocket’s autonomous flight computer observed that two of the nine Merlin 1D motors of the GPS III SV04 booster appeared to be running early than the schedule, then talk. The computer immediately stopped the power-up process to avoid what could otherwise have been a “difficult” (ie stressful or harmful) startup. SpaceX quickly began inspecting the rocket within 24 hours, but was unable to detect anything physically or electrically wrong with the Merlin 1D engines and engine section of the Falcon 9.

Out of an abundance of caution, SpaceX removed both misbehaving engines and shipped them to its development and test facilities in McGregor, Texas, where – somehow miraculously – the same premature startup behavior was replicated. on the test bench. After a large amount of increasingly granular inspections, SpaceX has finally reduced the probable cause to a tiny hydraulic line feeding one of the engine’s gas generator relief valves. In a seemingly random subset of relatively new Merlin 1D engines, SpaceX eventually found that a line of vendor-supplied relief valves were sometimes clogged with a protective lacquer that Koenigsmann likened to “red polish”.

Used to selectively exclude parts of the engine tubes during a surface finishing process known as anodizing, the paint was unsuccessfully removed on a random selection of engine parts or was accidentally channeled into a block by over-cleaning. Ultimately, for whatever reason, that tiny block was enough for the affected Merlin 1D engines to constantly attempt to fire a tiny fraction of a second early.

Basically, when SpaceX discovered the possible cause and cleared out the blocked piping, every previously affected Merlin 1D engine worked perfectly, confirming both the cause and the cure for the Falcon 9’s October 2 outage.

Astronauts go into quarantine

In anticipation of SpaceX’s seemingly simple solution to the gas generator problem, Steve Stich, NASA’s commercial crew program manager, revealed that SpaceX’s Crew-1 mission astronauts – Shannon Walker, Victor Glover and Mike Hopkins, and JAXA astronaut (Japanese) Soichi Noguchi – routine pre-launch quarantine procedures had begun in anticipation of the November 14 launch.

Stich also offered a more specific schedule for Crew-1, starting with an integrated static fire test of Falcon 9 and Crew Dragon NET on November 9 and a full dress test on November 10 before the first launch attempt on November 14. In particular, thanks to random orbital dynamics, a successful launch on November 14 would allow Crew Dragon to increase its orbit and meet with the International Space Station eight and a half hours after takeoff, three times faster than the more common transit of 27.5 hours. .

Stay tuned for updates as the mission launch date approaches.