SpaceX had hoped to launch a new prototype of its Starship megarocket — the system NASA may use to land astronauts on the moon — on Thursday, but Elon Musk’s rocket company was forced to stand down in the final seconds of the countdown.

Issues with a component in the launch tower, which connects the rocket to ground support equipment, triggered multiple holds. Flight controllers ultimately decided to scrub the launch attempt to investigate the problem.

A new launch date has not been announced. Musk said that if the issue can be fixed quickly, the company could try again to launch Starship on Friday.

The test flight would have been the 12th overall for Starship but the first launch of the new third-generation Starship, dubbed V3, which is bigger, more powerful and a step closer to being fully reusable.

The 408-foot-tall rocket was fully fueled Thursday on a new launchpad at SpaceX’s Starbase facility on the southern tip of Texas.

The launch attempt was closely watched — as the full test flight will be, whenever it happens — because NASA hopes to use Starship to land its astronauts on the lunar surface. As part of the agency’s Artemis program, SpaceX and Jeff Bezos’ Blue Origin are each building lunar landers that NASA could use for a planned moon landing in 2028. The space agency aims to test one or both new vehicles in low-Earth orbit on the Artemis III mission late next year.

In addition, Musk, SpaceX’s CEO, confirmed plans Wednesday to take the company public in what might be the biggest-ever initial public offering. It could make Musk — who will hold 85% voting control over the company after the IPO and remain its CEO, chairman and chief technology officer — a trillionaire.

During the launch broadcast Thursday, SpaceX announced that it plans for Starship to one day fly cryptocurrency entrepreneur Chun Wang around Mars, but it provided few details about the journey.

Before that flight can happen, SpaceX must demonstrate that Starship can reach the moon.

Since Starship’s last test flight seven months ago, the rocket’s booster, known as Super Heavy, and its upper stage, called Ship, have undergone extensive redesigns. SpaceX added new engines on both, so together they will be able to generate around 18 million pounds of thrust.

Other upgrades included reducing the number of “grid finds” on the booster, which are features at the top that help to guide the rocket’s first stage back to Earth, and increasing the volume of Starship’s propellant tank.

The plan for Thursday’s suborbital test flight called for Starship to deploy 22 mock Starlink satellites and relight one of the upper stage’s six Raptor engines in space. The latter is an important capability for the vehicle to make deorbit burns to return to Earth from space.

The test was scheduled to last about 65 minutes. Similar to previous outings, the upper stage was expected to splash down in the Indian Ocean at the end. Eventually, however, SpaceX plans to make Ship reusable and “catch” it with mechanical arms on the launch tower at its Texas facility.

SpaceX has demonstrated similar catch maneuvers with Starship’s Super Heavy booster. This time around, though, the booster was going to land in the Gulf of Mexico, according to SpaceX.

The company faces a tight timeline to develop Starship. The rocket, which made its debut flight in 2023, suffered a string of failures last year, including an uncontrolled re-entry through Earth’s atmosphere and two midflight explosions as the upper-stage vehicles were accelerating into space. Nonetheless, SpaceX aims to have Starship ready for next year’s Artemis III mission, when NASA hopes the rocket’s upper stage will rendezvous with the agency’s Orion capsule (the vehicle that carried the Artemis II astronauts around the moon) in orbit.

If all goes well, SpaceX will then work to get Starship certified to carry NASA astronauts to the moon in 2028.