Raptor 3: Specs and Details explained
Last week, Elon Musk and SpaceX released detailed information on their newest iteration of the Raptor engine: Raptor 3. This article delves into the evolution of the Raptor engine, highlighting the changes and comparing it to other engines to understand its power and significance.
A Short History of the Raptor Engine
The Raptor engine was first introduced during the presentation of the Interplanetary Transport System, the initial iteration of what is now known as Starship. It was notable for being the first full-flow staged combustion engine to reach a testing stand. In a full-flow staged combustion engine, both the oxidizer and fuel are pre-burned to drive the pumps, optimizing thrust and efficiency without losses. The initial version of the Raptor featured numerous sensors, wires, and pipes, which is typical for engines in the testing phase. This version flew on Starhopper and early Starship prototypes (SN5-6 and SN8-15). By that time, its successor was already undergoing tests at the McGregor test facility.
raptor 1 is a comparatively messy engine but for good reason Credit: SpaceX
Raptor 2: A Major Development Leap
Raptor 2 marked a significant advancement in the Raptor engine’s development. SpaceX replaced bolted and riveted joints with welded ones, enhancing the engine’s structural integrity. Many redundant sensors were removed as the engine had already been tested under flight conditions. Raptor 2 was the first version installed on a booster and flew during the orbital campaign, including flights in the vacuum of space. Following its initial flight, engine shielding was added for additional protection.
raptor 2: a cleaner engine with fewer cables. credit: SpaceX
Raptor 3 overview and reveal
raptor 3 on the test stand in all its glory. credit: SpaceX
Elon Musk hinted at the development of the Raptor 3 in a post on X (formerly Twitter), where he revealed its thrust and chamber pressure. Recently, the full specifications of Raptor 3 were published, providing a comprehensive look at its capabilities. Musk also shared an image of the first production Raptor 3 SN1, which has a noticeably clean and streamlined appearance. Observers noted its resemblance to a render from the 2017 BFR presentation. Musk highlighted that many of the external components are now interconnected, thanks to advances in 3D printing technology that previously utilized their Draco engine and Rocket Lab’s Rutherford engine. Later, in response to a post, Tory bruno said,
“They have done an excellent job making the assembly simpler and more producible. So, there is no need to exaggerate this by showing a partially assembled engine without controllers, fluid management, or TVC systems, then comparing it to fully assembled engines that do.”
Tory Bruno’s reply, pointing out the supposedly “missing” components.
Later that very same day,. Gwyn Shotwell, SpaceX, and president. Posted on x an image of the very first Raptor hotfire with the caption “Works pretty good for a “partially assembled engine” in a total jab to Tory Bruno with Elon Musk posting more images of the hotfire with noticeably more ice. This hotfire was also spotted on NasaSpaceflight's 24 hour McGregor live stream.
Gwynne Shotwell witty follow-up with a metric tonne of eye candy.
raptor 3 specifications compared to to other engines
In this section, we compare the thrust in tons and specific impulse in seconds across different versions of the Raptor engine. Raptor 1 had a thrust of 185 tons, already a significant engineering achievement. Raptor 2 increased this to 230 tons. The latest Raptor 3 version further boosts the thrust to an impressive 280 tons, marking a 95-ton improvement over just two iterations.
A more accurate comparison of engines is through thrust density, which is the thrust divided by the exit area. This accounts for the varying sizes of engines and their different fuel types and cycles. According to a chart by Reddit user u/sarigolpaz, Raptor 1’s sea-level and vacuum versions were not the highest in thrust density, being surpassed by the Space Shuttle and SLS boosters. However, Raptor 2 and the subsequent Raptor 3 have become the most powerful rocket engines by thrust density, with increased thrust and maintained exit area. While maintaining a respectable efficiency of 350 seconds, which is not the highest. but when accounting for the thrust density, it makes this engineering marvel seem even more magical
the wonderful chart show. raptors pure power. courtsy of u/sarigolpaz
Elon Musk recently stated that "Raptor operates close to the ragged edge of physics," and Raptor 3’s specifications and design make this statment all the more belivable.
