Science

The SpaceX Starship prototype ignites six engines and ignites a large brush fire

The SpaceX Starship prototype ignites six engines and ignites a large brush fire
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SpaceX has successfully fired all six engines on its latest Starship prototype, taking an important step in ensuring the upper stage is ready for the rocket’s first orbital launch attempt.

Alas, the same successful static fire of a Starship upper stage – potentially producing almost twice as much thrust as that booster of SpaceX’s Falcon 9 rocket — superheated debris scattered hundreds of meters away, igniting a large bushfire. It’s not the first major fire caused by Starship activity in South Texas, and it likely won’t be the last.

The S24 starship completed its first successful static fire on Aug 9, igniting two Raptor engines. Several unsuccessful attempts to test additional engines followed later in the month, and SpaceX finally decided to replace one of Starship S24’s three Raptor vacuum engines in early September before trying again. After workers installed the new engine and buttoned up ship 24, the stars finally aligned on September 8th.

At the beginning of the test, SpaceX pumped several hundred tons of liquid oxygen (LOx) and a much smaller amount of liquid methane (LCH4) into ship 24 in about 90 minutes, creating a crispy layer of frost wherever the cryogenic liquids touched the uninsulated steel tanks of the Rocket. No frost formed on Starship’s upper methane tank, meaning SpaceX loaded only methane fuel into internal “header” tanks intended to store propellant for landings. So the hundreds of tons of liquid oxygen were probably intended as ballast, reducing the maximum load Starship could put on the rig holding it to the ground.

This potential stress is significant. Equipped with upgraded Raptor 2 engines, Starship S24 could have produced up to 1380 tons (~3 million lbf) of thrust when it first fired all six at 4:30 p.m. CDT. In addition to smashing the record for the most thrust generated during a starbase rocket test, ship 24’s engines burned for nearly 8 seconds, making it one of the longest static burns ever conducted on a starship test bed.

Several bushfires were visible almost immediately after clouds of dust and steam cleared. Most likely, the combination of extreme force, heat, and burning duration obliterated the almost entirely unprotected concrete surface beneath Ship 24. Despite ongoing evidence that all of Starship’s static fire operations would be easier and safer with the systems, SpaceX still refuses to install serious water flood or flame deflection systems on Starbase’s test stands and launch pads.

Instead, SpaceX relies on a single mediocre spray nozzle and high-temperature concrete (probably Martyte) beneath its steel Starship test benches, which probably wouldn’t be suitable for a rocket ten times weaker than Starship. In several instances, starships have shattered this weak martyte layer, creating high-velocity ceramic shards that damage their undersides or Raptor engines, necessitating repairs and creating risky situations. Therefore, since there is essentially no attempt at all to tame the high-velocity, multi-thousand-degree Raptor exhaust, starbase static fire tests almost always ignite small grass fires and cause minor damage, but these fires rarely propagate.

It appears the random bushfire of September 8 burned down at least several dozen acres. (NASAspace flight)

Ship 24’s first six-engine test was not as successful, although the spacecraft appeared to survive unscathed. Most likely eight long seconds of blast furnace conditions melted the top layer of surrounding concrete and shot a hailstorm of tiny superheated globules in almost every direction. In fact, something was ready to burn in almost every direction, and a fire started. In several locations to the south and west, shrubbery caught fire and began to burn unusually aggressively, quickly growing into walls of flame that raged across the site. To the east, debris even made its way into a SpaceX dumpster, the contents of which easily caught fire and burned for hours.

Finally, around 9 p.m. CDT, firefighters were able to close in on the safe launch pad and missile, but the main fire had already spread south, out of range. Instead, they began controlled burns near SpaceX’s roadblock in hopes of clearing the scrub and preventing the fire from spreading (though unlikely) to SpaceX’s starbase factory and the homes and residents of Boca Chica Village.

The nature of the estuary-like terrain and wetlands mean this is the case very Stopping fires at choke points is easy, so the fire likely never posed a real threat to Boca Chica residents, SpaceX employees, or spectators. It was also unlikely that SpaceX’s launch facilities would be damaged or that Starship S24 would be damaged from the start, as both are surrounded by a combination of concrete aprons, empty earth fields and a highway.

Still, the fire-burned “bush” is a protected habitat in a state park and wildlife refuge. While fire is a natural and often necessary element of many habitats, including some in Boca Chica, this is the second major bushfire caused by Starship testing since 2019, which may be less than desirable. Fighting fires around starbases generally requires at a minimum that firefighters enter, or even drive on, protected wetlands and salt flats, the impact of which on wildlife and habitats could ultimately be as devastating as the fire itself.

SpaceX’s Federal Aviation Administration (FAA) Programmatic Environmental Assessment (PEA), which gave the company’s existing Starbase Texas facilities and launch plans a full green light earlier this year, only talks about fire [PDF] a handful of times. However, repairing and preventing future damage to wetlands is addressed dozens of times and is the subject of numerous conditions SpaceX must meet before the FAA will grant Starship an orbital launch license.

Ultimately, since the FAA approved this PEA in full awareness of a 2019 bushfires caused by Starhopper (an early Starship prototype) which may have been as bad or worse than the one from 2022, chances are it plays a role small Role in ongoing launch licensing process, but chances of it becoming a showstopper are close to zero. Still, it would likely benefit SpaceX at least as much as it does Boca Chica’s surrounding wilderness if it could make changes that prevent major bushfires from becoming a regular “random” event.

The SpaceX Starship prototype ignites six engines and ignites a large brush fire






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