A series of problems that prevented NASA from conducting a fueling test of its “mega moon rocket” this week may not be resolved in time to try again next week, NASA officials said Friday.
“We hope that there’s something that is fairly straightforward and needs to be adjusted or is easily resolved and we can do that at the pad and do it in fairly short order,” Mike Sarafin, the mission manager for NASA’s Artemis moon program, told reporters Friday.
If not, however, the rocket might need to be rolled back to its assembly building, causing a further delay.
Earlier this month, NASA rolled the towering Space Launch System rocket to its launchpad at the Kennedy Space Center for the first time with great fanfare for a series of tests ahead of its first launch. The rocket, which has been under development for years and is billions of dollars over budget, is designed to launch NASA’s astronauts to the moon for the first time since the end of the Apollo era.
The first launch in NASA’s Artemis program will send the Orion crew capsule into orbit around the moon without any people onboard. That had been scheduled for this spring. But with the problems NASA has encountered on the pad, it is not clear when that launch would occur.
Sarafin said the soonest the refueling test could take place now is next Thursday.
Known as a “wet dress rehearsal,” the test is meant to fully fuel the rocket’s two stages with more than 700,000 gallons of super-cold liquid oxygen and liquid hydrogen. Then NASA is to conduct a simulated countdown in preparation for the rocket’s first launch later this year.
But ever since the SLS was rolled out to the launchpad, NASA has encountered glitches: a leak in a line supplying liquid hydrogen, problems with temperature readings of propellant, malfunctioning fans used to pressurize the mobile launch tower.
Last week, NASA discovered a problem with a helium pressure valve on the rocket’s second stage that is designed to prevent liquids or gases from flowing in the wrong direction. Crews on the ground were not able to access the small part, just three inches long, in the rocket’s second stage, and said they would have to replace it once they rolled the rocket back to its assembly building.
With the valve malfunctioning, NASA said it would not attempt to fuel the second stage after all, meaning some key parts of the test would not be able to be performed.
On Thursday, NASA had to stop the fueling procedure for the first stage, too, after crews discovered a leak. “When you have hydrogen leaks, and you have ambient oxygen out there, you only need an ignition source to close the fire triangle,” Sarafin said. “So it was a flammability risk, and we knocked the test off as a result of that.”
During the truncated test, they were able to load only 5 percent of the liquid hydrogen and 49 percent of the liquid oxygen.
NASA officials knew they would run into problems with a rocket as massive and complicated as the SLS. It stands 322 feet tall, taller than the Statue of Liberty, and is more powerful than the Saturn V rocket that flew astronauts to the moon during the Apollo era. The avionics computers have 18 miles of cabling and more than 500 sensors.
The propellants are extremely cold and fickle — the liquid oxygen is kept at minus-297 degrees Fahrenheit, the liquid hydrogen at minus-423 degrees. Because the rocket has never flown, crews need time to learn how it operates in a real-world environment.
Despite the setbacks, NASA has learned a great deal and has gathered a lot of data about the rocket and how it operates, Charlie Blackwell-Thompson, NASA’s Artemis launch director, said. Finding problems is the point of the tests, she said, and is not uncommon for such a massive rocket that has never flown before.
“While we did not get all the way through the planned activities, we certainly accomplished quite a bit,” she said. “History has shown it’s been a challenge for pretty much anybody that’s done anything of this magnitude."
After NASA had to pause the test because the temperature limit on the liquid oxygen exceeded expected ranges, Wayne Hale, a former NASA flight director and Space Shuttle program manager wrote on Twitter that “preventing a catastrophic pressure surge (‘geyser’) in cryogenic systems is very tricky. Shuttle got that concern well in hand over years of practice. Not surprising that tweaking the procedures takes time for a new rocket’s ground system.”
As for the leak in the hydrogen line, he said that “a leak the first time is almost to be expected. But not satisfactory.”
The most recent setbacks will feed criticism of the rocket, which has been derided as the “Senate Launch System” because it provides jobs in key congressional districts.
Recently, NASA’s Inspector General took aim at the rocket, saying his office had calculated the cost for its first three flights to be $4.1 billion each, a price he said was “unsustainable.” But NASA and industry groups have pushed back against that analysis, saying it includes a wide array of costs, including staffing at major NASA centers, that are not directly related to the rocket’s operations.
While the launch date remains in flux, Sarafin said that he is “confident we’re going to get there.” But he added: “If you want an exact date, I can’t give that to you right now.”