Why NASA aborted the launch of its Moon rocket for the second time, and what happens now

The US space agency NASA was forced to abort its Artemis 1 mission to the Moon for the second time in a week, after engineers could not fix a leak of liquid hydrogen during the fuelling of the tanks of the rocket engine. A similar problem had aborted the scheduled launch of the mission on August 29 as well.

The #Artemis I mission to the Moon has been postponed. Teams attempted to fix an issue related to a leak in the hardware transferring fuel into the rocket, but were unsuccessful. Join NASA leaders later today for a news

conference. Check for updates: https://t.co/6LVDrA1toy pic.twitter.com/LgXnjCy40u

— NASA (@NASA) September 3, 2022

NASA Artemis 1 launch aborted: What went wrong?

NASA said on its website: “Teams encountered a liquid hydrogen leak while loading the propellant into the core stage of the Space Launch System rocket. Multiple troubleshooting efforts to address the area of the leak by reseating a seal in the quick disconnect where liquid hydrogen is fed into the rocket did not fix the issue. Engineers are continuing to gather additional data.”

On August 29 too, there was an issue of insufficient cooling of one of the four engines of the rocket. Over the week, NASA engineers had worked on the problems and thought they had fixed it. But the liquid hydrogen leakage recurred multiple times during the fuelling ahead of Saturday night’s launch, with engineers continuously engaged in firefighting.

After the leak appeared for the third time, NASA decided to call off the launch at 11.17 am EDT, or 8.47 pm in India. The launch was scheduled for 2.17 pm EDT (11.47 pm India), when a two-hour launch window was to open.

Is this twin failure unusual?

This is a new rocket, and many launches do not succeed in the first attempt. The failure was not unexpected. Even before the first attempt last Monday, some experts were sounding a note of caution.

I don’t want to be a Debbie downer but I rate the chances of #Artemis1 launch on Monday at about 50/50 not counting weather. It’s the first launch of a new complex rocket and there are likely still bugs to be worked out. Sorry if that makes folks upset but best to be realistic

— Wayne Hale (@waynehale) August 28, 2022

A couple of years ago, SpaceX’s first launch of NASA astronauts, which was the first such launch from American soil since the retirement of NASA’s space shuttles, reached the final minutes of the countdown before the mission was aborted, The New York Times recalled in an article. Weather was to blame on that occasion, and the launch took place three days later. On Saturday, NASA was targeting a two-hour launch window, starting 11.47 pm India time.

“Lots of launches do not get off the ground on the second try, either,” The NYT report said. A hydrogen leak can — and does — happen.

“As the smallest of molecules, it is difficult to work with, leaking through the smallest of gaps. Often, leaks do not show up until the fuel lines are chilled to ultracold temperatures of minus 423 degrees Fahrenheit, where hydrogen becomes liquid. Worse, there is no way to check except during a countdown when liquid hydrogen starts flowing into the rocket,” The NYT said.

What happens now?

The flight of Artemis 1 is the first in what NASA intends to be a new age of space exploration, returning humans to the Moon, and aiming further into deep space. So NASA will try again.

There are launch windows available on September 5 and September 6, but it was not clear immediately whether NASA would take another shot at sending the mission so soon.

“We go when we are ready. We don’t go until then… This (launch holdbacks) are part of the space business… We have to be ready for the scrubs (calling off the launch),” NASA administrator Bill Nelson said in an interview with NASA TV.

“We’ll go when it’s ready.” NASA Administrator @SenBillNelson remarks on the Sept. 3 launch attempt of the #Artemis I flight test to the Moon. Updates are expected from the team as early as 4pm ET (20:00 UTC). https://t.co/dMVnvEQcfC pic.twitter.com/ClBhVRexLs

— NASA (@NASA) September 3, 2022

Nelson said the mission management team would explore all the possibilities, but that the launch looked more likely to happen in October now.

“If it has to happen in October, though the launch window opens in early October, it would more likely happen in the middle of October,” he said, citing the scheduled departure of a space crew to the International Space Station in early October.