Rocket test paused
Failed fueling attempts may lead to delays on NASA’s new launch system
NASA is pausing a key test on its mega moon rocket, a decision that could delay the first launch of a vehicle that’s already behind schedule and over budget.
After three failed attempts to load the Space Launch System rocket with propellant, NASA has decided to return the rocket — with the Orion spacecraft stacked on top — to the Vehicle Assembly Building in Florida before attempting a fourth “wet dress rehearsal.” This will allow NASA to make repairs and permit an off-site supplier to upgrade a facility that caused some of the testing problems.
“It’s a very delicate dance in order to bring a rocket alive, fuel it up,” Tom Whitmeyer, NASA’s deputy associate administrator for Common Exploration Systems Development, said Monday during a news conference. He noted that there’s a learning curve when preparing to fly a rocket for the first time.
“(With) any new launch system when it first goes through this process, this is the type of thing you learn,” Whitmeyer said.
The space shuttle and Saturn V rocket had similar experiences prior to their first missions in 1981 and 1967, respectively. Still, returning to the Vehicle Assembly Building next week could delay the Space Launch System’s first mission, Artemis I.
NASA officials have been hesitant to give a date for this first uncrewed mission around the moon with the Artemis Program, which is seeking to land the first woman and person of color on the moon in 2025. Last week, they said launch windows for the uncrewed mission were available between early June and early August. On Monday, they said early June would be challenging.
Greg Autry, a clinical professor of space leadership, policy
and business at Arizona State University, expects the rocket’s first launch will be delayed several months. He’s forecasting Artemis I will lift off in fall 2022, as NASA wants to conduct another wet dress rehearsal prior to launch. A successful wet dress rehearsal would help reduce risks on launch day.
The pressure to prepare thoroughly and efficiently is particularly fraught, he said.
“Previous delays and cost overruns have made (Space Launch System) into a political football in Congress,” Autry said in an email, “and a launch failure for Artemis I could be an existential threat to the entire program. Everyone knows this, even if they won’t say it, and that reinforces the tendency to extreme caution and delay. It’s hard to get out of that trap and make a bold decision that risks failure.”
Charlie Blackwell-Thompson, NASA’s Artemis launch director, said the agency is examining three different options for conducting its next wet dress rehearsal. All of these options start with returning to the Vehicle Assembly Building.
The first two options would require multiple trips to this building. The rocket would return next week, be repaired, go to the launch pad for testing, return again to the assembly building for final preparations and then go back to the launch pad for liftoff.
The third option, however, would reduce the back and forth treks of the machinery by conducting a wet dress rehearsal right before launching the Artemis I mission. That means the rocket could return to the Vehicle Assembly Building next week, roll to the launch pad this summer, undergo testing and then launch shortly after.
That plan would save time because moving the combined Space Launch System rocket and Orion spacecraft is no small endeavor.
The two vehicles reached Launch Pad 39B at NASA’s Kennedy Space Center on March 18. It took 10 hours and 28 minutes, moving at top speeds of 0.8 miles per hour, to travel four miles to the launch pad.
Then the rocket had to be prepared before NASA could attempt loading propellant in its first wet dress rehearsal on April 3. In addition to loading the Space Launch System with propellant (super-cold liquid hydrogen and liquid oxygen), NASA technicians use this test to practice countdown procedures and validate critical models and software interfaces. Although propellant is loaded onto the rocket, the engines are not ignited during a wet dress rehearsal.
NASA scrubbed this April 3 test before loading any propellant into the rocket. A problem with fans prevented technicians from pressurizing the rocket’s ground structure, which made it unsafe to load the propellant.
The second test was scrubbed on April 4. NASA loaded some liquid oxygen into the rocket but did not load liquid hydrogen because a valve on the rocket’s ground structure would not open.
NASA then discovered a different valve issue before its third wet dress rehearsal, which prompted the agency to plan a “modified” test that would load propellant on April 14. Technicians planned to load the core rocket stage with liquid oxygen and liquid hydrogen, but they were not going to fully load the upper stage because of the valve issue. On launch day, the upper stage ignites after the core stage and two solid rocket boosters have been emptied and jettisoned.
This third test was called off after technicians discovered a liquid hydrogen leak.
Both the upper stage valve and hydrogen leak will be addressed when NASA returns to the Vehicle Assembly Building. This also provides time for an off-site supplier of gaseous nitrogen — which is used inside the rocket before the technicians load propellant — to upgrade its facility.
Overall, NASA officials said they were pleased with the rocket’s hardware. The problems have largely involved getting the rocket to work with its ground systems, which are used to load propellant into the rocket and support the vehicle prior to launch.
“It sounds like the repairs are relatively minor,” Phil Smith, a space industry analyst at BryceTech, said in an email. “This is not really a big deal at all.”
And these types of difficulties aren’t unusual prior to a rocket’s first launch, said Blackwell Thompson, the Artemis launch director.
During a wet dress rehearsal for the Saturn V rocket that sent Apollo astronauts to the moon, technicians spilled 2.7 million liters of super-cold liquid oxygen. According to a NASA history article, this caused a monthlong delay in testing as workers repaired the leak and ruptured tank.
A similar propellant-loading test for the space shuttle caused thermal insulation to fall off, Smith said. Technicians repaired it and conducted additional testing prior to launch.
“Putting it into context,” Blackwell-Thompson said, “I would say we’re within family of our experience in the past.”