July 16 (UPI) — SpaceX on Thursday scrubbed the planned 13th test light of its massive Starship megarocket just seconds before it was set to lift off from the company’s Texas Starbase.

The launch was abruptly canceled just before the “Super Heavy” booster was about to ignite its multiple engines.

“Standing down from today’s flight test attempt,” launch commanders posted on X, without immediately offering a further explanation.

It remained unclear when another launch would be scheduled.

In the build-up to the planned launch, the company says it is aiming to fine-tune the performance of third version of the most powerful rocket ever built with Thursday’s mission — specifically the Super Heavy booster.

During the 12th test flight May 22 it encountered several hiccups, including slight differences in engine startup at separation stage causing the directional flip of the booster to be off by approximately 90 degrees.

The booster was supposed to perform a sustained burn to a controlled landing in the gulf, but the engine failure meant it fell back to Earth instead in a “hard splashdown,” SpaceX said in its launch report.

The Federal Aviation Administration said there were no reports of public injury or damage to public property from the mishap.

In response, SpaceX said in a blog post that “the startup sequence has been modified to be more robust to timing variability and more reliably flip in the desired direction, which is done to increase overall performance.”

Also during Flight 12, the Super Heavy booster encountered problems when attempting its boostback burn in which five of its 33 engines malfunctioned when attempting to re-light. This caused the boostback burn to end early.

“The Super Heavy on this upcoming flight has hardware modifications to improve re-light reliability along with updates to engine alarms and aborts to match the conditions seen in the multi-engine flight environment,” Space X said.

The Starship system has two parts: the Super Heavy booster and the spacecraft itself, also called Starship, or sometimes just “Ship.”

Flight 12 was the first launch of the third version of the system, which is the first capable of deep-space flight. Plans call for Starship to carry Artemis 4 astronauts to the surface of the moon in a mission set for late 2028.

In another notable element of Thursday’s Flight 13, Starship for the first time will carry V3 Starlink satellites to space as the company aims to “greatly expand” its communications network’s capacity and user speeds.

As part of this initial test, Starship is set to deploy 20 satellites which will extend solar arrays and antennas in a bid to connect with the larger Starlink constellation via high-capacity lasers as they will be on the same suborbital trajectory as Starship.

Those satellites are designed to burn up on reentry into the Earth’s atmosphere approximately 20 minutes after deployment.