As is routine, SpaceX CEO Elon Musk has taken to Twitter to offer a few details about the status of Starship, its Raptor engines, and a few upgrades planned for both.
In mid-December, Musk revealed even more ambitious plans to upgrade Starship by stretching its propellant tanks and adding another three Raptor engines, potentially boosting the ship’s maximum thrust by 50% and substantially improving payload performance. These latest details are focused on an upgraded version of the Raptor engine and on additional changes to Starship’s structural design and assembly process.
According to Musk, as SpaceX continues to ramp up ground testing of the upgraded engine variant, “Raptor 2 now operates routinely at 300 bar main chamber pressure.” For context, on February 10th, 2019, just days after SpaceX began testing the first full-scale Raptor prototype ever completed, the engine briefly reached a main combustion chamber pressure just shy of 269 bar (3900 psi). That narrowly beat records set by Russia’s RD-270 and RD-180 engines, the latter of which is used on ULA’s Atlas V.
— Elon Musk (@elonmusk) February 11, 2019
It took 18 months before Musk revealed clear proofthat at least one Raptor prototype sustained such high chamber pressures over a minute or more of steady-state operations. The same engine peaked at an impressive 330 bar (~4800 psi), briefly producing 225 tons (~500,000 lb) of thrust and soundly beating out Russia’s never flown RD-701 engine, which crested 290-300 bar in testing. Another ~18 months after that milestone, Raptor isn’t quite operational in the sense of supporting orbital-class launches but the engine isn’t far from its first and has since supported dozens of Starship static fires and seven flight tests – five of which occurred in a period of just six months.