The SpaceX Starship booster withstood a record-breaking 31-engine static fire.
The most powerful static fire in the history of rocketry was achieved by the Super Heavy Booster 7. One engine was manually disabled just before the static fire, while the other engine shut down while trying to ignite. The Raptors did a static fire that lasted about five seconds.
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Team turned off 1 engine just before start & 1 stopped itself, so 31 engines fired overall.
— Elon Musk (@elonmusk) February 9, 2023
But still enough engines to reach orbit! https://t.co/QYx3oVM4Gw
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Super Heavy Booster 7 survived the test without catching fire, exploding, or popping its tanks, despite the static fire. The rocket's tanks were filled with liquid oxygen and methane propellant to counteract the thrust of its engines. The stool-like Orbital launch mount, which survived the test in one piece, held Starship down with 20 clamps to counteract any remaining thrust. It is likely that the static fire was a success because of the fact that the only orbital-class launch site survived.
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33 Raptor engine static fire attempt soon pic.twitter.com/wrsWIDt4Vt
— SpaceX (@SpaceX) February 9, 2023
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The test was more than that, as 31 engines were fired, but only one engine stopped. In the late 1960s and early 1970s, the Soviet N1 rocket launched four times with 30 NK-15 engines. N1 set a record for the most thrust produced by a single rocket, generating up to 9000 tons of thrust at liftoff, despite not being successful in its test flights. The odds of Super Heavy Booster 7 breaking the historic thrust record have been reduced.
It could have. The Raptor 2 engine can generate up to 507,000 lbs of thrust at sea level. As low as 40% or 92 tons of thrust is what Raptor is supposed to be. With 33 engines operating nominally at their minimum throttle setting, Super Heavy would have produced 3036 tons of thrust during today's static fire, not a record 33 Raptor engine static fire attempt soon.
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Views from drone of Booster 7's static fire test pic.twitter.com/KN4sk1nohf
— SpaceX (@SpaceX) February 9, 2023
A full-thrust static fire would be the most valuable test of all time, but it would also be the riskiest and most stress for the rocket and pad. Tom says that the record was broken by SpaceX. The father of the Raptor engine is likely to still get information from the engineers he used to work with. If the rocket it built became the most powerful in history, it would be a big deal for the company.
During the first sea-level static fire in 1965, the first stage of Saturn V produced around 3400 tons of thrust. N1's booster was never static-fired, likely contributing to its failure. The Space Shuttle and SLS use a combination of solid rocket boosters and liquid engines that can't be tested together on the ground. The most powerful ground test in the history of rocketry is likely to be the 29-Raptor static fire by Starship.
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Booster 7 static fire
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To be confident in the ability of Starship to launch and fly a safe distance away from the launch site, a full 33 engine test is needed. The FAA could deny a license without a perfect 33-engine static fire if it were to approve a launch license for Starship. It is possible that a second 33-engine static fire attempt may not be necessary if all 33 engines are active. A fully-stacked Starship was fully fueled for the first time in January, demonstrating what the rocket will look like just before liftoff.
In January 2023, a fully-stacked Starship was fully fueled for the first time, demonstrating how the rocket will look just before liftoff. (SpaceX)
If the test results are good and there is no damage to the pads, it will likely focus on finishing Starship 24. Booster 7 will be reinstalled on top of ship 24. Once all those tasks are completed, Ship 24 and Booster 7 will be ready to support the first launch attempt of the fully-stacked Starship. After the static fire on February 9th, Musk and Shotwell agreed that the launch could happen as early as March 2023.
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Rewatch Super Heavy Booster 7's historic static fire may be within reach after today's test.