NASA’s massive SLS rocket’s latest wet dress rehearsal test has again been aborted prematurely, this time due to a hydrogen leak. Teams are looking at the data to try to fix the problem. They will then consider a new test. Will the fourth attempt be the right one?
The Artemis program must mark the next era of human exploration. Working with commercial and international partners, NASA will establish an enduring presence on the Moon to prepare for missions to Mars. The Artemis 1 mission, scheduled for this year, is the first stage of this major project. Its goal is to send an Orion capsule twice around the Moon before returning to Earth.
While waiting to be able to launch this mission, NASA engineers must operate a wet dress rehearsal test. During this final pre-launch test, the thrusters of the massive SLS must be filled with liquid hydrogen and liquid oxygen. Various countdown scenarios in preparation for takeoff are also operated. During this time, everything is controlled, measured and verified so that everything goes as planned on D-Day.
Problem: Nothing goes as planned.
Three failed attempts
On April 3, NASA had already tried to power its launcher for the first time. Engineers eventually had to stop the test before loading began due to a pressurization problem on the mobile launcher that keeps dangerous gases out of the confined areas where technicians work.
The next day, a vent valve then got stuck at the top of the launch vehicle’s mobile structure (which supports the rocket upright on the launch pad), forcing NASA to abort its second test after refueling began. . The rocket boosters, which contained about half of the liquid hydrogen and oxygen, were then emptied by ground crews.
This Thursday, the engineers made a third attempt. Again, not everything went as planned. The teams indeed aborted the test after observing a leak of liquid hydrogen (LH2) on the structure located at the base of the mobile launcher which connects to the central stage of the rocket. According to the agency, the leak was discovered when the liquid oxygen tank was about 49% full, while the liquid hydrogen tank was about 5% full.
Since then, the reservoirs have been drained. The teams are currently examining the data to establish an action plan to remedy this hydrogen leak, after which a new attempt should be scheduled.
And that’s only the beginning.