The blast-off of the first US rocket in 50 years capable of carrying humans to the moon was called off on Monday morning after last-minute problems with an engine cooling system.
The 322ft-tall Space Launch System rocket had been due to lift off from launch pad 39B at Florida’s Kennedy Space Center, the same site that witnessed the launch of Apollo 17, the last US mission to the moon.
The launch, set for 8.33am local time, was put on hold and then scrapped after Nasa assessed a number of last-minute problems, including with one of the hydrogen “bleed” lines used to cool the engines before ignition. Back-up launch windows are available for a second attempt on Friday, with a third launch option next Monday.
Nasa said later in the day that it was still assessing the problem and had yet to determine if it would be able to launch on Friday.
After 12 years of development and significant cost overruns, the first launch of the moon mission is a significant test for Boeing, the rocket’s main contractor. Nasa sought to paint the delay as part of the usual teething problems for a new rocket.
“It’s just part of the space business, and part of particularly a test flight,” said Bill Nelson, the Nasa administrator. “You don’t light the candle until it’s ready to go.”
In a statement after the cancellation, Nasa said its team “ran out of time in the two-hour launch window” as engineers scrambled to find the problem with the engine cooling system ahead of the scheduled lift-off.
“Launch controllers were continuing to evaluate why a bleed test to get the RS-25 engines on the bottom of the core stage to the proper temperature range for lift-off was not successful,” Nasa said. The procedure that caused the problem was one that Nasa had not been able to test in the run-up to the planned launch.
The first flight of the rocket is set to open a new era in human space exploration as the US races China to put astronauts back on the lunar surface. Monday’s mission was due to carry an unmanned Orion capsule on a six-week test flight around the moon, a prelude to its first human mission in 2024 and a moon landing in 2025.
The moon missions are the first step in Nasa’s Artemis programme, which was set up with the eventual goal of carrying astronauts to Mars and beyond. It comes after decades in which the US gave up on human exploration of deep space, leaving it reliant for much of the time on renting space on Russian rockets to carry its astronauts into orbit.
“Prior to the Artemis programme, there were many countries that were looking towards China” for leadership in space, said Mike Gold, a former Nasa official in charge of policy and partnerships.
Speaking at an event the day before the launch, Gold said the US had “failed time and time again to sustain a programme” in space beyond low-earth orbit, leaving an opening for Beijing to take a lead and making it essential for the US to respond.
China, which has landed three robotic craft on the moon, has said it is planning to build a lunar base with Russia, and has invited other countries to join the project.