SpaceX is scheduled to make a second attempt at launching Starship to Earth’s orbit tomorrow (April 20) from the company’s Starbase facility in Boca Chica, Texas. The flight was originally scheduled for April 17 but was scrubbed at the last minute due to a booster valve issue. Even if it gets off the ground, it’s far from certain it will complete its mission.
“I guess I would just like to set expectations… low,” SpaceX CEO Elon Musk said in a Twitter Space meeting on April 17 ahead of Starship’s first scheduled launch attempt.
Starship, a 400-foot, two-stage rocket designed to fly humans to Mars, is the tallest spacecraft ever built. Its maiden orbital test flight is a highly anticipated event in the space community that, if successful, will pave the way for SpaceX attempting more ambitious space missions with the rocket.
It took SpaceX five attempts to successfully land a prototype of Starship’s upper stage from six miles in the sky. The first four attempts all ended with explosions for different reasons. Tomorrow’s orbital flight involves a much larger spacecraft that aims to climb more than 100 miles above sea level, so a lot more could go wrong.
“The orbital flight is substantially more complicated because it involves flying both the Super Heavy booster and the Starship orbital vehicle together for the first time,” Micah Walter-Range, president of Caelus Partners, a space consulting firm, said in an email. “That requires a delicate balance of all the systems working together.”
The plan for tomorrow’s test is to launch Starship to orbital altitudes first and then have it complete a full orbit around the Earth. There are several possibilities where the mission could end prematurely.
Scenario 1: Malfunction before liftoff
That’s what happened during Starship’s first attempt on April 17. A frozen pressure valve on the rocket’s booster prevented it from igniting properly, forcing SpaceX to abort the mission. SpaceX’s launch team didn’t discover the problem until about 10 minutes before scheduled liftoff during a final ground check.
Scenario 2: Not reaching desired altitudes
Musk said last month there is only a 50 percent chance of Starship landing from its orbital flight in one piece. And it might not reach orbital altitudes at all, if something breaks down early in the mission.”I’m not saying it will get to orbit, but I am guaranteeing excitement. So, won’t be boring!” he said at a Morgan Stanley conference on March 7.
Whether Starship can reach its desired altitudes depends on the separation phase, when the rocket’s booster drops away from its upper stage. Separation is “a point in the flight where new systems often fail because the timing is a little bit off or the systems don’t play well together,” said Walter-Range. “That was the case for SpaceX back in the company’s early days when they first started flying the Falcon One.”
With multiple launch attempts, Musk estimates there’s a 80 percent of Starship reaching orbit by the end of 2023 and it will probably take a few more years to achieve full usability, he said at the conference.
Scenario 3: Explosion before or upon landing
Landing is the trickiest part of a Starship test, based on the rocket’s previous flights to suborbital space. Four prototypes exploded during those tests, all during the landing phase.
A rocket could crash at landing for various reasons, such as descending too fast, engines igniting too late, or one of its landing legs not extending properly.
“If we get far enough away from the launchpad before something goes wrong, I would consider that to be a success,” Musk said at this week’s Twitter Space meeting. “Just don’t blow up the launchpad.”
That’s a reasonable goal, Walter-Range said. “Even with all the experience SpaceX has gained, the first flight is always challenging,” he wrote in an email.
