Elon Musk’s SpaceX was set to launch a prototype of its Mars rocket Starship in its highest-altitude “hop” test from the space company’s Texas facilities on Tuesday, but the launch was aborted shortly before the countdown concluded.

The launch was intended to be a key trial for a rocket system that Musk hopes will land humans on the moon and eventually Mars.

But an automatic engine abort occurred with just 1.3 seconds remaining in the countdown. SpaceX announced on its web broadcast it was done for the day, and there was no word on when it might try again.

SpaceX, which previously said its launch schedule is likely to change, has launch opportunities all day Wednesday and Thursday, according to filings with the U.S. Federal Aviation Administration (FAA).

Starship, a rocket system standing 120 metres tall when mated with its super-heavy first-stage booster, is designed to carry humans and 90 tonnes of cargo to the moon and Mars. It is the space company’s planned next-generation fully reusable launch vehicle, the centre of Musk’s ambitions to make human space travel affordable.

SpaceX has carried out two hop tests this year using rudimentary, single-engine rocket prototypes at its Boca Chica, Texas, launch site. Those prototypes launched about 150 metres into the air and landed on a concrete slab roughly a minute later.