The Starship is nothing without its Raptor engines they produce The thrust, to help the Starship escape the earth’s gravitational pull, and propel it on its interplanetary journeys. The thrust they produce has to be enormous, as the Starship is meant to lift heavy payloads of up to one hundred tons.
This is important, if musk’s dream of planting people on Mars is to materialize all the stuff, necessary for life, will be transported to the planet by the Starship. SpaceX is not short of powerful
rockets, part of its roster of spacecraft is the falcon nine which is partially reusable.
It is capable of blasting payloads up to twenty-two thousand eight hundred kilograms to low Earth orbit. Falcon nine is powered by the Merlin engine, developed in-house by SpaceX. However, the Starship needed something more powerful. And SpaceX decided to build a new engine, naming it the Raptor with the design.
SpaceX is introducing lots of insane concepts that few rocket companies have tried. The result is a beast masquerading as a rocket engine. Each Raptor engine weighs about one point five tons and will supply 230 tons of thrust to weight ratio to the Starship.
The engine itself is evolving, with Raptor 2 now deep into testing at SpaceX’s McGregor test site. Raptor 1 already sported 185t of thrust. However, with Raptor 2, that increases to 230t. Raptor 2 is also “greatly simplified while increasing thrust. Half the cost at more thrust,” Musk added.
The current peak thrust R2 operated at is 247 tons, so SpaceX is confident 250t will be achieved, which is “obviously essential to making SS work.” The visual changes between Raptor v1 and v2 are apparent, with less cabling and plumbing around the engine.
While it’s easily visible around the entire engine, the turbopump appears to have been shrunk in size, and the plumbing has been consolidated. Raptor 2 SN5 appears to be a Raptor Boost engine, which means it lacks the ability to gimbal or steer, and cannot throttle as low as Raptor Center engines. This engine is far more than just a step up from V1.
It was a complete redesign; everything from turbomachinery to chamber nozzle to its electronics has been redesigned. This allowed items to be deleted and consolidated while the turbopumps are more robust. Citing his dislike of flanges, many have now been converted to welds.
“At high pressures and cryogenic temps flanges are a nightmare,” Musk noted. “700-800 bar in places, 11000psi, going to welded from flanges is helpful.” Musk also noted that the preburner controllers have moved to boxes, rather than being all over the engine.
future changes to the point where Raptor will not need a shroud – this will reduce its mass and stop being “a pain in the ass, especially for gimbaling engines,” per Musk. With more deletion and integration, the engine will be flameproof, and losing shrouds is a good mass saving.
Probably can operate at 330 bar sustained in the main chamber, without having the pre burner pressure be too high.” This will remove choke points, resulting in less pressure loss. Raptor testing has been proceeding well at SpaceX McGregor. That engine was shown in action during the presentation.
The remaining challenge is mitigating against the engine chamber melting. The exhaust of The Raptor engine is expelled at over ten times the speed of sound. If that is not crazy enough for you, the fuel in the chamber burns at temperatures high enough to melt the walls of the chamber.
If you wonder why the wall does not melt, that’s because of the clever way the flame is kept away from the walls, by manipulating the flow of the gas. Supercold fuel is also pumped through the walls as additional security. The Raptor engine works as most rockets do.
Expelling gases fast enough to push the spacecraft forward. However, a lot of clever engineering makes The Raptor a mighty rocket. The engines depart in their design from standard fare for rockets, as SpaceX opted for a full-flow staged combustion cycle.
Inside the Engine, ignition is handled by the dual redundant spark plug-lit torch igniters, which means there is no need for a dedicated, consumable igniter fluid as found in the Merlin. The Raptor combines methane and oxygen that is deeply cooled.
SpaceX is well into the process of qualifying Raptor for Starship’s first
orbital launch attempts. According to that timeline, ten seconds shy of three minutes after liftoff, Starship’s Super Heavy booster will shut down and separate from the spacecraft.
Starship will then ignite either three or six Raptor engines for a bit less than six minutes, to boost itself within the vicinity of orbital velocity. Curiously, the same timeline makes no mention of a deorbit burn, without which the first “orbital” test
flight will technically be suborbital, even if Starship is traveling very close to orbital velocity.
Regardless, the document confirms that Starship’s orbital insertion burns will be approximately 5.5-6.5 minutes long. The maximum stamina required from its Raptor engines, in other words.
Rephrased, in its current design, Starship will never be able to reach orbit without Raptor engines, capable of continuously operating for around six minutes.
Up until high-altitude Starship test flights began in December 2020, the extent of Raptor’s long-duration capabilities and thus the state of SpaceX testing was effectively a
mystery. Ultimately, as Musk notes, if SpaceX manages to boost “Raptor 2” to 230 tons of thrust, a Super Heavy booster with 33 mostly identical engines would have a peak liftoff thrust around 7600 tons.
Translating to a thrust to weight ratio of more than 1.5. For a large rocket with liquid propulsion only, a thrust to weight ratio is very respectable, and improves acceleration off the launch pad, reduces
gravity losses in the first few minutes of ascent, and thus boosts overall efficiency.
Already, Musk’s implication that 33 engines could ultimately be installed on Super Heavy, is a departure from comments the CEO made barely a last month. When he revealed a base increase from 28 to 29 engines, with the possibility of expanding to 33 down the road.
Also new is the implication that SpaceX is considering adding three more vacuum-optimized engines to Starship’s six planned Raptors, leaving ships with six Raptor Vacuum engines, and three sea level-optimized engines, the same variant on Super Heavy.
The vacuum version will keep the upper stage moving after being disconnected from the booster, to optimize for performance in space. The vacuum version has a nozzle skirt extension, making it bigger.
The difference can be easily noticed when The two are placed side by side, in other specifications and components. The two variants are identical. The high-performance Raptors are not exactly cheap initially. Each engine cost SpaceX a million dollars to build, but SpaceX is working on cutting it down to two hundred and fifty thousand dollars.
A pop, the cost is significant to Musk as he tries to make interplanetary trips affordable to everybody. This is why the Raptor 2 engine is designed to require as minor refurbishment as possible for multiple uses. His company is working to ramp up production and be able to make the rocket engines in mass.
The immediate goal is to make five hundred of them per year. However, if musk’s plan to have a fleet of a thousand starships, making thousands of flights is to occur, that capacity will need to be increased significantly. A single Starship can use up to forty one Raptor engines.
The lower stage may require thirty-one C level variants, although the actual number has varied during the testing of the Starship. The upper stage will take six Raptors, a mixture of both The sea level and vacuum variants. The sea level engines are needed for landing both on earth and on Mars.
While SpaceX is racist to finish the Raptor engines, lots of people are monitoring the progress.
NASA for example has tapped the Starship to help land its. Astronauts on the moon, as it revitalizes its space exploration program with Project Artemis.
It is working on a twenty twenty five deadline, but beyond the moon, the Raptor engine is insanely essential to NASA. As it hopes to use the Starship to get astronauts to Mars in the long run trips, to even more distant planets like Jupiter are also on the cards.
This is why it agreed to give two point nine billion dollars to SpaceX, to fund the spacecraft development. Another big name waiting on the Raptor engine is the US military.