Shortly after Teslarati reported that the first operationalized Raptor had shipped to McGregor, Texas for its first full-scale static fire tests, SpaceX CEO Elon Musk took to Twitter to post the first official photos of the “radically redesigned” engine preparing for its critical debut test fire in Texas.
Designed with extreme reliability, efficiency, and reusability in mind, the Raptor seen in Musk’s photos is rated for just shy of 2.5 times the thrust of Merlin 1D at 200 tons (450,000 lbf) and has been commonized across both stages of BFR (Starship and Super Heavy) to spread out development costs and speed up the next-generation rocket’s orbital launch debut.
Aside from revealing some impressive photos of the first upgraded Raptor preparing for a static fire test, Musk went into a bit more detail on the future of the engine and its probable development path, describing Raptor in its current iteration as a sort of compromise between achieving nominal performance and minimizing the cost and timescale to arrive at a flight-ready engine. Currently stationed at SpaceX’s McGregor, Texas development and testing facilities, Raptor appears to feature an expansion ratio somewhere in between Merlin 1D (optimized for sea-level) and MVac (optimized for vacuum).
This increases the stress on the nozzle during ignition and operation at normal atmospheric pressures but it also improves engine efficiency once Starship (or Super Heavy) rises above the thickest parts of Earth’s atmosphere, even if a medium-expansion nozzle still can’t touch the performance of a giant vacuum-optimized bell like those used by MVac. As such, BFR in its earliest iterations will be significantly less capable than a fully-optimized version of the rocket when it comes to high-energy Earth/lunar orbits and interplanetary trajectories, a challenge that can at least initially be hurdled by accepting much lower nominal payload capabilities and relying on brute-force performance, much like Falcon 9 and Heavy.
Assuming the first hot-fire tests of the full-scale, operationalized Raptors go well, three of the next-gen engines could support the first hop tests of a full-scale Starship prototype sometime in the next few months, potentially as early as late-February or March. Musk also reiterated that Starship’s complimentary booster – known as Super Heavy and set to begin initial prototype assembly as early as April – will feature 31 Raptor engines capable of producing upwards of 12.4 million pounds of thrust (62,000 kN) at liftoff. However, Musk indicated that the sheer value of 31 advanced Raptor engines also means that the first Super Heavy flights may only feature a partial complement of engines in case the vast booster experiences a failure, far from uncommon during the first few launches of a new rocket.