While two previous launch attempts were marred by fuel leaks, including a sizable one earlier this month NASA engineers could not contain, NASA officials said they are now confident they have fixed the problem after running a fueling test earlier this week.
Still, there is a tropical depression in the Caribbean that could threaten the Florida Space Coast and force NASA to once again delay the launch. A decision on that could come Friday evening or Saturday, NASA said, since it needs a couple of days to roll the vehicle back to its assembly building at the Kennedy Space Center.
The potential track of the storm “has changed dramatically over the last few days,” said Tom Whitmeyer, NASA’s deputy associate administrator. “It’s not a named storm. We really want to continue to try to get as much information as we can so we can make the best possible decision for the hardware.”
NASA has a lot of experience from the space shuttle days in dealing with storms that roll up the Florida coast, especially at this time of year, he said. The space agency did not want to call off a launch prematurely in case the storm shifts direction.
“We have a step-by-step, measured approach for looking at weather, seeing which direction it’s going,” he said. “I don’t think we’re cutting it close. I think we’re cutting it just at the right time.”
After years of setbacks and delays, NASA officials are eager to launch the SLS rocket for the first time, which would mark the first major step in its Artemis program to return astronauts to the moon. This launch would have no astronauts on board, and is seen as a test of the vehicle before the space agency flies humans.
But NASA has run into a series of problems in getting the rocket off the ground. At the end of August, NASA said a bad sensor forced them to waive off the flight attempt. Then, on Sept. 3, it had to scrub the launch again after it could not contain a large liquid hydrogen leak.
This week, NASA tested the repair of the leak by fueling the rocket using a “kinder, gentler” approach. But even with a more careful process to load the propellant slowly and under easier pressures, engineers discovered a hydrogen leak that forced NASA to pause the fueling while it worked to stem the flow.
Ultimately, NASA’s engineers were able to get the rocket fueled, despite overcoming yet another leak that they said they were able to manage. Overall, the test was “very successful,” said John Blevins, NASA’s chief SLS engineer.
Despite the setbacks, the team was “actually very encouraged,” Whitmeyer said, calling it a “good accomplishment.”
Hydrogen, the lightest element, is kept in liquid form at minus 423 degrees Fahrenheit, and NASA has had a difficult time loading it into the rocket’s tanks without it leaking.
NASA officials said Friday that they have also received a waiver from the U.S. Space Force that would allow it to proceed with the flight. The Space Force requires the batteries on the SLS’s termination system, which is designed to destroy the rocket should it go wildly off course and threaten a population center, to be recharged every so often to ensure they are in good working order.
The initial timeline called for the batteries to be recharged after 20 days. That was extended to 25 days to allow for an early September launch attempt, and now the Space Force has allowed NASA to extend it further to accommodate next week’s attempt.
The launch would be the first in NASA’s Artemis campaign to eventually return astronauts to the lunar surface. This first mission would send the Orion spacecraft, without any astronauts on board, in orbit around the moon. It would be followed by a crewed flight that would again orbit, but not land, on the moon, perhaps in 2024 — with a landing to come in 2025 or 2026.