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Timing of NASA’s moon launch may depend on emergency detonation system

The system, which is designed to destroy the SLS rocket if it veers off course and threatens population centers, needs to be recharged every few weeks

NASA postponed the launch of its massive Space Launch System rocket and Orion spacecraft to the moon after problems during two separate attempts last week. (Jonathan Newton/The Washington Post)
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Like all big rockets, NASA’s Space Launch System is outfitted with powerful engines and thousands of gallons of highly combustible propellants capable of lifting a booster the size of a tall building off the Earth and traveling many times the speed of sound out of the atmosphere.

It also carries a bomb.

Formally known as the Flight Termination System, it is a detonation system designed to destroy the rocket in case it starts to veer wildly off course and threaten people on the ground. In the dangerous world of rocketry, it’s a vital and ubiquitous safety component, operated by the military. But it’s also creating a bit of a headache for NASA as it struggles to launch the SLS rocket for the first time.

The Space Force requires the batteries on the SLS’s termination system to be recharged every so often to ensure they are in good working order. The problem for NASA is that can only be done in the rocket’s assembly building, meaning they would need to perform the arduous work of rolling the 322-foot-tall rocket off the pad, where it is now, back to the building four miles away — a journey that can take about eight hours each way.

That would further delay a launch that last week was called off twice because of other technical problems, including a massive leak of the liquid hydrogen the rocket uses for fuel.

During a briefing on Thursday, Jim Free, NASA’s associate administrator for the exploration systems development mission directorate, said that if the Space Force grants a waiver to extend the flight-termination battery requirement, NASA would aim to launch the rocket on Sept. 23 or Sept. 27.

If the Space Force decides the batteries do need to be reset, however, and SLS would have to be rolled back to the vehicle assembly building, Free said, “We obviously will support that and stand down and look for our next launch attempt.”

NASA already got the Space Force to extend the requirement from 20 to 25 days so that it could attempt a launch in the latter part of its last launch period, which ended Tuesday. This time, the waiver would have to cover a total of more than 40 days.

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.

After years of delays and setbacks, NASA officials are eager to get the first mission off the ground. But they’ve struggled with a string of issues. The first attempt was scrubbed because of a bad engine sensor reading. Then, on Saturday, they could not control a large hydrogen leak and said there was also a sudden increase in the pressure of the fuel line that caught officials by surprise.

Now, it’s struggling with the constraints of the termination system, and it is not clear whether the Space Force’s Space Launch Delta 45, which oversees what’s known as the Eastern Range, would grant the extension.

“The first thing is to protect the public, and the Eastern Range takes that mandate to protect the public very seriously,” said Wayne Hale, a former NASA space shuttle flight director who now chairs a NASA advisory committee. Rockets, he said in an interview, are “effectively a bomb, it’s a huge bomb,” and the 45th Space Wing goes to great lengths to ensure the termination systems are working before it allows launches to occur.

“They are consummate professionals,” said Wayne Monteith, the former commander of the 45th Space Wing. “If something goes wrong, they are the team you want on console.”

NASA said Tuesday evening that engineers would replace the seal that malfunctioned during the hydrogen leak on the launchpad, instead of rolling it back to the assembly building. That would allow engineers to test the seal by running the liquid hydrogen, which is kept at minus-423 degrees Fahrenheit, through it. That test is expected to occur on Sept. 17, NASA said, but could slip.

“Performing that work at the pad also allows teams to gather as much data as possible to understand the cause of the issue,” NASA said in a statement.

There is a downside, though: The longer the rocket is outside, the longer it is exposed to the fickle weather that is common along the Florida Coast this time of year.

“We are mindful that we’re out there in the elements when we’re at the pad,” Mike Sarafin, the Artemis mission manager, told reporters after the scrubbed launch on Saturday.

While it does the repair work, NASA said it would “set up an enclosure around the work area to protect the hardware from the weather and other environmental conditions, but enables engineers to test the repair under cryogenic, or supercold, conditions.”

It noted that in order “to meet the current requirement” the Space Force has for the flight termination batteries, it “would need to roll the rocket and spacecraft back” to the assembly building to reset the batteries.

If that is the case, NASA may not be able to attempt another launch until the next opportunity, a roughly two-week period that begins Oct. 4. The SLS’s ability to launch is determined by the position of the Earth and moon, since the Orion spacecraft cannot be in darkness for more than 90 minutes at a time. Its solar arrays need to stay illuminated so that they can provide power to the spacecraft and ensure it maintains the correct temperature.

This story has been updated.