“We won’t be launching in this launch period,” said Jim Free, associate administrator for NASA’s Exploration Systems Development Mission Directorate. “We’re not where we wanted to be.” Free said the stack, including the Space Launch System rocket and Orion spacecraft, must return to the Vehicle Assembly Building unless they receive a range waiver, which is run by the US Space Force. NASA Administrator Bill Nelson recalled that the shuttle was sent back to the Vehicle Assembly Building 20 times before launch — and noted that the cost of two cleanups is far less than one failure. “We don’t launch until we think it’s right,” Nelson said. “These teams have worked on this and this is what they’ve come to. I see it as part of our space program, where safety is at the top of the list.” The scrub was called at 11:17 am. ET, three hours before the start of the launch window. Artemis I was scheduled to lift off Saturday afternoon, but those plans were scrapped after team members discovered a liquid hydrogen leak that they spent most of the morning trying to fix. Liquid hydrogen is one of the propellants used in the large core stage of the rocket. The leak prevented the launch team from being able to fill the liquid hydrogen tank despite trying various troubleshooting procedures. Previously, a small leak had been seen in this area, but it became much larger on Saturday. The team believes that an overpressure event may have destroyed the soft seal in the liquid hydrogen junction, but they will have to take a closer look. “This was not a manageable leak,” said Mike Sarafin, director of the Artemis mission. It is the second time in a week that the space agency has been forced to halt the countdown to launch due to technical problems. The first launch attempt, on Monday, was canceled after several issues arose, including a system meant to cool the rocket’s engines before launch and various leaks that appeared as the rocket was being refueled. The liquid hydrogen leak was discovered at 7:15 a.m. Saturday. ET in the quick disconnect cavity that feeds the rocket with hydrogen in the engine section of the core stage. It was a different leak than the one that occurred before Monday’s launch. The launch controllers heated the line in an attempt to make a tight seal, and liquid hydrogen flow resumed before leaking again. They stopped the flow of liquid hydrogen and proceeded to “close the valve used to fill and drain it, then pressurize a ground transfer line using helium to try to reseal it,” according to NASA. This troubleshooting plan was not successful. The team tried the first design again to heat the line, but the leak reappeared after they manually restarted the liquid hydrogen flow. There was a 60 percent chance of favorable weather conditions for the launch, according to meteorologist Melody Lovin. The Artemis I stack, which includes the Space Launch System rocket and the Orion spacecraft, continues to reside at Launchpad 39B at the Kennedy Space Center in Cape Canaveral, Florida. The Artemis I mission is just the beginning of a program that will aim to return humans to the moon and eventually land crewed missions on Mars. Nelson said the issues during the first two scrubs did not cause delays in future Artemis missions. In recent days, the launch team spent time addressing issues such as hydrogen leaks that appeared before Monday’s planned launch before it was cleaned up. The team also completed a risk assessment of an engine air conditioning problem and a foam crack that also appeared, according to NASA officials. Both were considered acceptable risks for the launch countdown, according to Mike Sarafin, Artemis mission manager. On Monday, a sensor on one of the rocket’s four RS-25 engines, identified as engine #3, reflected that the engine could not reach the proper temperature range required to start the engine during launch. Engines must be thermally conditioned before running very cold propellant prior to start-up. To prevent the engines from experiencing temperature shocks, the launch controllers gradually increase the pressure of the liquid hydrogen tank in the center stage in the hours before launch to send a small amount of liquid hydrogen to the engines. This is known as “bleeding”. The team has since determined it was a bad sensor providing the clue — they plan to ignore the faulty sensor moving forward, according to John Blevins, Space Launch Systems chief engineer.
Mission Overview
Once Artemis I launches, Orion’s journey will take 37 days as it travels to the moon, orbits it and returns to Earth — covering a total of 1.3 million miles (2.1 million kilometers). Although the passenger list does not include humans, it does have passengers: three mannequins and a Snoopy plush toy will ride on the Orion. Expect to see views of Earthrise similar to those first shared during the Apollo 8 mission in 1968, but with much better cameras and technology. The inaugural mission of the Artemis program will begin a phase of NASA’s space exploration that intends to land different crews of astronauts in previously unexplored regions of the Moon — the Artemis II and Artemis III missions, planned for 2024 and 2025 respectively — – and eventually deliver manned missions to Mars. CNN’s Kristin Fisher contributed to this story.
