“We will not be launching in this launch period,” said Jim Frey, associate administrator for NASA’s Exploration Systems Development Mission Directorate. “We are not where we wanted to be.”
Frey said the stack, including the Space Launch System rocket and Orion spacecraft, should retreat to the Vehicle Assembly Building, unless they receive a waiver of range, which is operated by the US Space Force.
NASA Administrator Bill Nelson stated that the shuttle was brought back to the Vehicle Assembly Building 20 times before launch—and noted that the cost of two scrubs was much less than a failure.
“We don’t shoot until we think he’s right,” Nelson said. “These teams have worked on it and that’s the conclusion they came up with. I look at this as part of our space program, where safety is at the top of the list.”
The scrubber was called at 11:17 a.m. ET, three hours before the launch window began.
Artemis was scheduled to take off on Saturday afternoon, but those plans were scrapped after team members discovered a liquid hydrogen leak and spent much of the morning trying to solve it. Liquid hydrogen is one of the propellants used in the rocket’s large core stage. The leak prevented the launch team from being able to fill the liquid hydrogen tank despite trying various troubleshooting procedures.
Previously, a small leak was seen in this area, but it became a much larger leak on Saturday. The team thinks the overpressure event may have damaged the soft seal of the liquid-hydrogen contact, but they’ll need to take a closer look.
“This was not a manageable leak,” said Mike Sarafin, Artemis’ mission manager.
It’s the second time in a week that the space agency has had to pause the countdown to launch in the face of technical problems. The first launch attempt was canceled, on Monday, after various problems arose, including with a system intended to cool the rocket’s engines before takeoff and various leaks that appeared during the refueling of the rocket.
A liquid hydrogen leak was detected Saturday at 7:15 a.m. ET in the rapid separation cavity feeding the rocket with hydrogen in the engine section of the primary stage. It was a different leak than the one before the launch that cleared up on Monday.
The launch controllers heated up the line in an effort to get an airtight seal and resume the flow of liquid hydrogen before a leak occurred again. They stopped the flow of liquid hydrogen and proceeded to “close the valve used to fill and drain it, then increase pressure on a ground transmission line with helium to try to re-seal it,” according to NASA.
The troubleshooting plan did not work. The team tried to put the first plan in place again to heat the line, but the leak recurred after they manually restarted the flow of liquid hydrogen.
According to meteorologist Melody Lovin, there was a 60% chance of favorable weather conditions for the launch.
The Artemis I stack, which includes the Space Launch System rocket and Orion spacecraft, remains on Launchpad 39B at the Kennedy Space Center in Cape Canaveral, Florida.
The Artemis I mission is just the beginning of a program aimed at returning humans to the Moon, and eventually landing manned missions on the surface of Mars. Nelson said that problems during the first two scrubs caused no delays in future Artemis missions.
In the past few days, the launch team has taken time to address issues, such as a hydrogen leak, which surfaced before Monday’s planned launch, before it was removed. The team also completed a risk assessment for an engine conditioning issue and a foam breakage that also emerged, according to NASA officials.
Both were considered acceptable risks before the countdown to launch began, according to Mike Sarafin, Artemis mission manager.
On Monday, a sensor in one of the rocket’s four RS-25 engines, identified as Engine 3, showed that the engine could not reach the appropriate temperature range required to start the engine on takeoff.
Engines must be thermally conditioned before super-cold propellant flows through them before takeoff. To prevent the engines from experiencing any temperature shocks, launch controllers gradually increase the pressure of the liquid hydrogen tank in the primary stage in the hours leading up to launch to send a small amount of liquid hydrogen to the engines. This is known as “bleeding.”
The team has since determined that it was a bad sensor providing the reading — they plan to discard the faulty sensor moving forward, according to John Blevins, chief engineer of Space Launch Systems.
Once Artemis I is launched, Orion’s journey will take 37 days as it travels to the Moon, orbits it and returns to Earth – traveling a total of 1.3 million miles (2.1 million km).
Although the passenger list doesn’t include any humans, it does include passengers: three mannequins and a plush Snoopy ride in Orion.
Expect to see views of Earthrise similar to what was first shared during the Apollo 8 mission in 1968, but with much better cameras and technology.
CNN’s Kristen Fisher contributed to this story.