SpaceX has successfully completed a hot fire test of its Super Heavy booster, the first stage of its Starship rocket, which is designed to be fully reusable and capable of carrying humans to the Moon and Mars. The test, which took place on Friday, August 25, 2023, at SpaceX’s Starbase facility in South Texas, was a major milestone for the company and its ambitious space exploration plans.
What is the Super Heavy booster?
The Super Heavy booster is the largest and most powerful rocket stage ever built, with a height of 70 meters and a diameter of 9 meters. It has 33 Raptor engines, which are SpaceX’s next-generation liquid-fueled engines that use a combination of liquid oxygen and methane as propellants. The Raptor engines have a thrust of about 2,200 kilonewtons each, giving the Super Heavy booster a total thrust of more than 72,000 kilonewtons at liftoff. That is nearly double the thrust of NASA’s Saturn V rocket or Space Launch System, which are the most powerful rockets ever flown.
The Super Heavy booster serves as the first stage of the Starship launch system, which consists of two stages: the Super Heavy booster and the Starship upper stage. The Starship upper stage is a 50-meter-long spacecraft that can carry up to 100 passengers or 100 tons of cargo to low Earth orbit, the Moon, Mars, or beyond. The Starship upper stage also has six Raptor engines, three for sea-level operations and three for vacuum operations.
The Starship launch system is intended to be fully reusable, meaning that both stages can land back on Earth after each mission and be refueled and reflown multiple times. This would drastically reduce the cost and increase the frequency of space launches, enabling SpaceX to achieve its long-term vision of making humanity a multiplanetary species.
What happened during the hot fire test?
A hot fire test is a common practice in rocket development, where the engines are ignited for a short duration while the rocket is held down to the ground by clamps. This allows the engineers to test the performance and functionality of the engines and the rocket systems under realistic conditions, as well as to verify that the ground infrastructure can handle the immense heat and pressure generated by the engines.
The hot fire test of the Super Heavy booster on Friday was the second one performed by SpaceX, following an earlier attempt on August 6, 2023. The first test ended prematurely after 2.74 seconds, and four of the 33 engines either did not ignite or shut down early. After that test, SpaceX rolled back the booster to its production site, where it added a “hot staging ring” between the booster and the upper stage. This ring is meant to facilitate “hot staging”, a tricky maneuver where the upper stage engines ignite before the booster engines have finished their burn. This would allow for a smoother transition between the stages and increase the performance of the launch system.
The second hot fire test lasted for about six seconds, which was close to the planned duration. According to SpaceX founder Elon Musk, all 33 engines ignited during the test, but two of them shut down early due to sensor errors. However, he said that 31 engines would have been enough to reach orbit. He also characterized the test as “successful” on Twitter, and SpaceX later confirmed that no major issues were detected during the test.
What are the next steps for SpaceX?
The successful hot fire test of the Super Heavy booster was a critical step towards the next launch of the Starship launch system, which could happen as soon as late March or early April 2023. The launch would be an orbital test flight, where the Starship upper stage would separate from the booster and attempt to reach orbit around Earth. The booster would then try to land back on Earth near its launch site, while the upper stage would reenter the atmosphere and splash down in the ocean.
The orbital test flight would be a huge challenge for SpaceX, as it would involve many complex maneuvers and technologies that have never been demonstrated before. For instance, SpaceX would have to perform hot staging for the first time in history, as well as control the reentry and landing of both stages using aerodynamic surfaces and thrusters. Moreover, SpaceX would have to deal with regulatory hurdles and environmental concerns from various authorities and stakeholders.
However, if SpaceX succeeds in achieving orbit with its Starship launch system, it would be a historic achievement that would pave the way for future missions to the Moon and Mars. SpaceX has already won a contract from NASA to use Starship as part of its Artemis program, which aims to land humans on the lunar surface by 2024. SpaceX also plans to send an uncrewed Starship mission to Mars in 2024, followed by a crewed mission in 2026.
SpaceX’s Super Heavy booster passes key test ahead of Starship launch