SpaceX test-fires Raptor engine on Starship test rocket

Video credit: SPadre / YouTube

A test-firing of a Raptor engine on the latest in a series of Starship test rockets Tuesday night in Texas moved SpaceX closer to performing a low-altitude “hop” to gather data on the vehicle’s launch and landing characteristics.

The single methane-fueled Raptor engine on the bottom of the Starship vehicle ignited a few minutes before 9 p.m. CDT Tuesday (10 p.m. EDT; 0200 GMT). The engine fired for several seconds, producing a blast of brilliant orange exhaust as the Starship stood on a test stand at SpaceX’s facility in Boca Chica, Texas.

The throttleable engine can generate up to 440,000 pounds of thrust. Three Raptor engines will be used to eventually power future Starship vehicles into the upper atmosphere, and orbital-class Starships will fly with six Raptors.

SpaceX is gearing up for a 500-foot (150-meter) hop test of the Starship vehicle. It’s not clear whether SpaceX will attempt further Raptor test-firings under the Starship, or perform a lower-altitude flight before attempting the 500-foot hop.

The test-firing Tuesday night occurred less than a week after NASA awarded SpaceX a $135 million contract to further develop the Starship vehicle as a human-rated lunar landing craft. NASA also inked contracts with Blue Origin and Dynetics to work on different lunar lander concepts.

NASA is seeking a commercially-developed lunar lander to to be ready as soon as 2024 to carry astronauts from lunar orbit to the moon’s surface and back. The NASA contract with SpaceX announced last week is the largest government investment in the Starship to date.

SpaceX envisions the Starship as a multipurpose vehicle, capable of launching from Earth with astronauts and private citizens, cargo, scientific experiments, communications satellites, and space telescopes. The Starship is designed to eventually be refilled with methane and liquid oxygen propellants in space, allowing the ship to travel to other planets and back to Earth for multiple trips.

A single Raptor engine is mounted underneath the Starship SN4 vehicle. Credit: Elon Musk/SpaceX

The Starship will function as the upper stage on a towering launch vehicle standing nearly 400 feet tall (120 meters). The first stage on the huge launcher, named the Super Heavy, will be powered by more than 30 Raptor engines, according to SpaceX.

Combined with the reusable Super Heavy booster, an operational Starship could haul more than 100 metric tons, or 220,000 pounds, of cargo to low Earth orbit, SpaceX said.

“Starship has the capability to transport satellites, payloads, crew, and cargo to a variety of orbits and Earth, lunar, or Martian landing sites,” SpaceX wrote in a Starship user’s guide released last month.

The Starship prototype currently being tested at SpaceX’s South Texas launch site is designated SN4. Three previous Starship vehicles were destroyed during pressure tests at Boca Chica, but SpaceX quickly moved on to the next Starship prototype as part of the company’s fast-paced iterative development process.

The next Starship in line, named SN5, could attempt a higher-altitude flight after SpaceX is done with SN4 testing.

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Follow Stephen Clark on Twitter: @StephenClark1.