SpaceX will attempt to relight Starship's engine in space

After the Starship spacecraft separates from the Super Heavy booster — just a couple minutes after liftoff — the Starship lights up its own six engines and continues firing itself closer to the speeds necessary to enter orbit around Earth.

Starship won’t actually go into orbit, as that’s not one of the goals of this test flight.

But the company will test out firing up one of the Starship’s own six Raptor engines for a second time after the initial burn that takes the spacecraft to aggressively faster speeds.

Being able to reignite an engine after it’s already fired once — and as it’s traveling through space — will be crucial to SpaceX figuring out the fuller picture of how Starship will eventually carry out more complex missions that reach Earth’s orbit, or even deeper into space.

“This is really important, something they haven’t done before,” said former NASA astronaut Garrett Reisman, who is now a SpaceX consultant and professor at the University of Southern California’s Viterbi School of Engineering. “These Raptor engines, are what we call ‘stage combustion engines.’ They’re very similar to the engines that we had on (NASA’s) space shuttle, although they work with different propellants and they’re complicated engines.

“They’re finicky little beasts, and it’s not so easy to light them up and shut them down and light them up again,” Reisman told CNN.