Starship Raptor Engine Passes Critical Test for Artemis and HLS

SpaceX has passed a test of starting a Raptor engine after cold soaking at temperatures meant to simulate coasting unpowered for days traveling to the moon.  This is considered a critical test to clear Raptors in the Human Landing System (HLS) to bring astronauts from the Artemis III mission down to the lunar surface in 2025 or '26.  The test only ran the engine for three seconds, since the object of the test was to verify starting at cryogenic temperatures and those temperatures go away pretty quickly.  The test was conducted in August but NASA's Artemis blog only posted about it Thursday (Sept. 14).  SpaceX tweeted a short, 18 second, video on X the same day, showing the test ignition and burn.  

Screen capture from the SpaceX video on X.

As for the Raptor engine test, NASA officials said its success gives the agency more confidence that SpaceX is progressing toward its Artemis 3 obligations. "These tests provide early and mission-like validation of the systems necessary for carrying astronauts to and from the lunar surface," agency officials wrote in the blog post. "Data reviews following these tests provide NASA with continually increasing confidence in U.S. industry's readiness for the mission."

This is the second major test of Raptor engine capabilities for NASA and Artemis.  In November '21, SpaceX ran the engine for the duration needed for the long descent to the moon, 281 seconds (4.5 minutes).  The Raptor also had its power level changed during the test to verify those mission requirements.  

You might recall that this June, NASA Associate Administrator Jim Free blasted Starship along with Boeing's Starliner as being fixed price contracts that haven't lived up to his expectations.  He doubted that SpaceX could meet a 2025 launch date and might force the mission out to '26. 

In the Aug. 8 press conference at NASA's Kennedy Space Center in Florida attended by Space.com, Free suggested the agency could leave off the moon landing for Artemis 3,if necessary, and fly an alternate mission with a crew. In that scenario, Starship would be used on a future mission (such as Artemis 4) for the first human lunar landing since Apollo 17 in 1972.

The agency is looking for multiple successful launches by Starship ahead of authorizing the landing with astronauts, among other milestones, Free said. (Indeed, NASA wrote in its blog post on Thursday that the agency will be watching the performance of Raptor engines during the second launch attempt by Starship.)

There are a few things SpaceX must demonstrate before a lunar landing in addition to getting Starship into orbit successfully.  Of these, the biggest hurdle seems to be successful orbital refueling.  If every Starbase launch is delayed by some agency, the next moon landing is also delayed.  Perhaps NASA might lean on the FAA, FWS, DOJ and any other government bureau trying to impede SpaceX's progress.