Teams at NASA’s Kennedy Space Center will try once again this week to complete a critical fueling test of the agency’s SLS rocket, which is tasked with launching the Orion spacecraft and its four-astronaut crew on a mission to the moon and back.
During an attempt of the test known as the wet dress rehearsal on Feb 2, sensors picked up a leak of hydrogen near the base of the rocket where the propellant is pumped into the rocket’s fuel tank. Super-cooled liquid hydrogen and oxygen are used as propellant to loft the massive SLS rocket off the pad and into space. Hydrogen molecules are very small, and can easily slip through even the tiniest of cracks. They are also highly flammable.
The leak, along with other issues like trouble closing Orion’s hatch, prompted mission managers to delay a potential launch of the Artemis II mission earlier this month and plan for a second wet dress rehearsal.
Since then, technicians have replaced the seals of the fuel lines supplying the rocket, and conducted additional tests of the equipment used to transfer liquid hydrogen from the ground to the rocket.
Last week, engineers partially filled the fuel tank with liquid hydrogen, giving them enough data to move forward with a new test. However, they did notice a reduction in flow of the fuel. NASA says engineers suspect a filter is to blame and have replaced it.
A second dress rehearsal is now scheduled for Tuesday, starting at 6:40 p.m. EST. The nearly 50-hour test simulates an actual countdown leading up to launch day, stopping 30 seconds before liftoff.
The critical fueling portion of the test will occur on Thursday, ahead of a simulated launch window opening at 8:30 p.m. EST. Launch teams will conduct two runs of the last 10 minutes of the countdown, simulating potential issues like technical or weather issues that may require them to stop and then restart the countdown.
The Artemis II crew – NASA’s Reed Wiseman, Victor Glover and Christina Koch, and Canadian Space Agency’s Jeremy Hansen – will not participate in the launch test. But the crew that’s responsible for securing their capsule will practice launch-day operations during the test.
NASA will not set a launch date until there’s a successful wet dress rehearsal and engineers have reviewed the data.
The earliest the Artemis II mission could launch is March 6.
