SpaceX has reportedly swapped a “suspect” Raptor engine installed on Starship serial number 10 (SN10) in record time, setting the company up for what appeared to be an excellent static fire just 48 hours after the first test.
In a February 24th tweet, CEO Elon Musk told followers that “one of [SN10’s three Raptor] engines is suspect, so we’re swapping it out.” Engine swap-outs have been a regular procedure for SpaceX’s Starship team as the company continually pushes the envelope of both Starship and Raptor prototype fidelity and implement major design changes and upgrades. Of the five Starship prototypes (including Starhopper) with intentional flights under their belts, all required at least one engine replacement before being cleared to launch.
Within ~18 hours of Tuesday’s “suspect” Starship SN10 static fire, SpaceX dispatched a replacement Raptor down the road from a nearby storage site. Within ~12 hours, the faulty engine had been removed and a backup engine installed in its place. Another ~12 hours after that, SpaceX teams cleared the launch pad for Starship SN10 to attempt a second static fire and (hopefully) qualify the rocket for flight.
Starship SN10 – set to be the sixth prototype to fly – is now part of that elite but buggy group of flightworthy test articles. For the most part, that bugginess is all according to plan: SpaceX’s ability to move and react with extreme speed is what allows the company to make such rapid progress and begin test flights as early in the development process as it does. That speed of action includes responding to the inevitable bugs that crop up while testing cutting-edge rocket prototypes.
Case in point, after Tuesday’s 5pm CST static fire, it took SpaceX less than 48 hours to pore through the test’s data, conclude that one of SN10’s three Raptor engines was “suspect,” select a replacement engine, remove the faulty engine, install that replacement, and fire up Starship SN10 a second time. Even SpaceX’s world-class reusable Falcon rockets would have a hard time challenging that engine swap turnaround. Taking a broader look at the lay of the land, NASA’s SLS rocket booster – outfitted with four former Space Shuttle engines – will reportedly require more than three weeks for teams to swap out a faulty valve in one of those four engines.
The first SLS Core Stage suffered an early abort during its first static fire test in mid January. As of publishing, NASA is now working towards a second static fire attempt in mid March – two full months later. By all appearances, SpaceX turned Starship SN10 around in 48 hours, performing what looked like a full-duration, nominal three-engine static fire on February 25th. Unlike February 23rd’s static fire, Starship exhibited no signs of an abort immediately after the test, whereas SN10 began large depressurization venting the second its Raptors shut down on Tuesday.
Unfortunately, everything will remain uncertain until SpaceX official confirms its plans, but Starship SN10 should be fully cleared for a launch attempt as early as Monday, March 1st if a data review of its Thursday static fire raises no red flags. Stay tuned for updates as SpaceX prepares to find out if the third time really is the charm.