Starship 24 Static Fires All Engines

After several days of standing by for a static firing, we finally got to see one yesterday.  Starship S24 was tested yesterday in the late afternoon at Starbase Boca Chica.  For the first time, all six engines in a Starship were tested at once; the three sea-level and three vacuum optimized Raptor 2 engines.  SpaceX has not stated what thrust the engines were wound up to, but the maximum rated thrust of the six is rated to almost 3 million pounds.  SpaceX's workhorse Falcon 9 is rated to 1.8 million pounds, so it's possible S24 was pushed beyond the Falcon 9 for a brief peak.  

Kicking off the test, SpaceX pumped several hundred tons of liquid oxygen (LOx) and a much smaller quantity of liquid methane (LCH4) fuel into Ship 24 in about 90 minutes, producing a crisp layer of frost wherever the cryogenic liquids touched the skin of the rocket’s uninsulated steel tanks. No frost formed on Starship’s upper methane tank, implying that SpaceX only loaded methane fuel into internal ‘header’ tanks meant to store propellant for landings. The hundreds of tons of liquid oxygen, then, were likely meant as ballast, reducing the maximum stress Starship could exert on the test stand holding it to the ground.

That potential stress is substantial. Outfitted with upgraded Raptor 2 engines, Starship S24 could have produced up to 1380 tons (~3M lbf) thrust when it ignited all six for the first time at 4:30 pm CDT. On top of smashing the record for most thrust produced during a Starbase rocket test, Ship 24’s engines burned for almost 8 seconds, making it one of the longest static fires ever performed on a Starship test stand.

Once the smoke from the test cleared, it was easy to spot that the test started a tiny, minor brushfire; which didn't stay that way very long.  We can say with absolute certainty it wasn't the first such fire that has been caused by a test there and most likely won't be the last.  Because of the saltwater marsh-like terrain around the pads it’s rather easy to stop fires at choke points, and the main concern was holding firefighters out of the area until the vehicle was made safe. 

Earlier in the day, a Spin Prime test was run on booster 7, and it looked like it involved more engines than any other test they've run.  Spin-prime tests flow high-pressure gas through the Raptors' pumps to spin them up without igniting anything.  This is the kind of test that caused the explosion under B7 back in July and has led to a more extensive amount of testing of these engines.  Whether or not they did the test on all 33 engines or only the outer 20 engines that aren't steerable, I haven't seen anything definitive.  

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Finally a short addition, just because it's interesting to look at. The T-Zero Systems Twitter account shared video this week of a Falcon 9 first stage landing on a drone ship, as seen from a SpaceX support ship at sea.  It's a 23 second video of the last few seconds of a Falcon 9 landing, showing the booster coming down at what appears to be a pretty steep angle to the vertical until straightening up immediately before touching down.  It's a view that's very different from how we ordinarily see these.