SpaceX is developing a massive methane engine called Raptor that will power its next-generation rocket, called Starship. So far, SpaceX has only performed a few pressure tests on Booster 4, their most complete Super Heavy booster. So, they will start by doing smaller static fires with just a few engines and then build up to the full 29. When Booster 4 lights up all 29 of its engines, it will produce a level of thrust 7 times greater than the Falcon 9. The only other rocket that comes close to this is the Soviet N1 rocket.
How SpaceX Will Test 29 Raptor Engines
It was a similar size to Starship and also featured a similar layout of 30 engines. Many of the failures were caused by explosive engines which led to a chain of other problems during launch. With much more advanced computer systems now, SpaceX will hopefully be able to shut down a failing engine before it turns into a grenade. This is a problem that SpaceX is hoping to solve with its Boca Chica facility.
But it’s not just the rocket itself that could cause problems during a static fire. The entire launch infrastructure surrounding the rocket plays a crucial role in keeping the rocket safe. Normally, launch pads use a flame diverter to deflect the intense exhaust away from the rocket and the launch pad. But SpaceX is taking a much riskier approach with Starship.
In the past, this has caused problems for SpaceX, with large chunks of concrete being thrown back up into the engine bay, completely destroying engines. In order to avoid this, SpaceX covers the concrete in an ablative coating called Martyte. Its main goal is to reduce the sound energy created by the engines, which can be extremely damaging to both the rocket and the launch pad. Another factor that SpaceX has to consider is the sheer amount of load on the vehicle when all 29 engines fire up.
The thrust puck at the bottom of the booster is designed to transfer all of the force from the engines onto the walls of the booster. This is something that SpaceX already does on both the Falcon 9 and Falcon Heavy rockets. On the Falcon 9, opposing engines are lit in pairs, 150 milliseconds apart, meaning the rocket reaches full power in just half a second. Part of the reason for having so many engines instead of just a few larger engines is redundancy.
If multiple engines shut down during a launch or landing, it won’t mean the rocket is destroyed, since the other engines can turn on or throttle up to compensate for the loss of thrust.
During a Starlink launch last year, a Merlin engine shut down during launch but the Falcon.
On the Falcon 9, only 3 engines are able to perform the landing burn, so there is nothing they can do if one fails to light. But since Super Heavy has way more engines than the Falcon 9, it will give it a much wider throttle range, allowing it to hover. No matter what happens during the first full static fire of Super Heavy, it’s guaranteed to be extremely exciting. Either way, it’s amazing to think about all of the incredible engineering that has gone into making not just the most advanced rocket engine ever made but also the enormous structures that sit on top of them.
Raptor engine development
SpaceX has developed and manufactured the Raptor family of full-flow, staged-combustion-cycle rocket engines for its Starship project. As opposed to the previously used kerolox (RP-1 kerosene and LOX) in the Merlin and Kestrel engines, “methalox” (“cryogenic liquid methane and LOX”) will power the new engine. Compared to SpaceX’s Merlin 1D engine used for Falcon 9 and Falcon Heavy, the Raptor engine has more than twice the thrust.
In the Starship system, Raptors are used both in the super-heavy-lift Super Heavy booster and in the spacecraft that is launched from Earth as the second stage and in LEO as an independent spacecraft. SpaceX’s Starship is planned for many applications, including Earth-orbit satellite delivery, deployment of the Starlink satellite constellation, lunar exploration, and colonization of Mars.
US Air Force awarded SpaceX a US$33.6 million contract to develop a prototype of its reusable Raptor engine for use on Falcon 9 and Falcon Heavy launch vehicles. SpaceX had to match with US$67.3 million in funding. In 2018, the contract work was supposed to be finished at Stennis Space Center and Los Angeles Air Force Base.