SpaceX Tests Raptor Engine, Prepares for Starship “Hop”

The commercial space company is getting ready to validate its former BFR for flight and its Crew Dragon for human flight.

February 7, 2019

William Kucinski

Hawthorne, California-based SpaceX has test fired its Raptor rocket engine at its Rocket Development and Test Facility, in McGregor, Texas. The Raptor is designed to power the Super Heavy first stage and Starship second stage launch vehicles. The two stages were referred to as the Big Falcon Rocket (BFR) up until late last year.

The news came as SpaceX founder and CEO Elon Musk posted a photograph and video of the test fire on social media. (Image courtesy: Elon Musk via Twitter)

The reusable Raptor engine is designed to deliver approximately 448,000 pounds of thrust through a highly efficient, but highly complex staged combustion process. Originally envisioned as “hydrolox” engine – one that burns a binary liquid oxygen (LOX) oxidizer and liquid hydrogen combustible, the Raptor is now a LOX and cryogenic liquid methane fueled launch vehicle. SpaceX shifted towards methane-based fuels after investigating the possibilities of in-situ methane production on Mars – one of SpaceX’s landing objectives.

Test firing – or “lighting the candle” – allows engineers to detect and remedy any issues in the engine design before launch. And while the combined Super Heavy and Starship vehicles won’t launch until the early 2020s, SpaceX has ramped up work on a specialized launch pad for a Starship Alpha prototype or “Starhopper” launch vehicle, designed to validate Starship powered landing capabilities.

SpaceX used the same method to validate its Falcon 9 launch vehicle, in that case the test vehicle was called the Grasshopper.

Read more: Blue Origin aims for crewed New Shepard launch in 2019

Starhopper will use three Raptor engines to lift off and ascend into low atmosphere and then reduce engine power and make a controlled descent later this spring. At this point the prototype has an assembled fuel tank, aft engines, stabilizer fins, and nose cone. It’s reflective, gleaming exterior is suspected to play a role in heat resistance, lowering weight through a reduced need for heat shielding.

The eventual Starship design will likely incorporate 7 Raptor engines, with an additional 31 powering the Super Heavy first stage launch vehicle. The Super Heavy will be nearly twice as powerful as the legendary Saturn V rocket used by NASA to reach the Moon during the Apollo program .

Concurrently, SpaceX is also readying for a potential Crew Dragon launch in March from Launch Complex 39A at NASA’s Kennedy Space Center on Merritt Island, Florida. The flight will not be manned, but will validate Crew Dragon capabilities.

William Kucinski is content editor at SAE International, Aerospace Products Group in Warrendale, Pa. Previously, he worked as a writer at the NASA Safety Center in Cleveland, Ohio and was responsible for writing the agency’s System Failure Case Studies. His interests include literally anything that has to do with space, past and present military aircraft, and propulsion technology.