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After several false starts, NASA finally launched its Artemis I mission in November last year. The big aim of the mission was to test out new hardware like the Space Launch System (SLS) rocket and the Orion spacecraft ahead of the crewed Artemis II mission.
Artemis II will be the first crewed launch using the new system and is currently scheduled for next year. This mission will see four astronauts travel into orbit around the Moon, making it the first crewed mission to travel out of low Earth orbit since 1972. It will be followed by Artemis III, which aims to land a crew on the Moon’s surface, launching in 2025.
Before a crewed launch, however, some of the hardware used in Artemis I needs to be refreshed. In a press conference this week, NASA officials shared more information about what had been learned from the Artemis I launch and what would be updated for Artemis II.
“Whenever you fly something new for the first time you’re going to learn something, and this is the case with Artemis I as well,” said Shawn Quinn, manager of the Exploration Ground Systems program.
The first area to be worked on is the mobile launcher, which is the structure that the rocket sits in while it is on the ground. During the launch of Artemis I, some damage to this structure was caused by the tremendous 3,000-degree Fahrenheit heat from the SLS’s boosters. The pressure from firing the engines blew the doors off two of the elevators within the mobile launcher. One of these elevators has now been repaired, with plans to harden the second one to get it ready for the next launch.
“Overall we’re very pleased with how critical systems performed, such as the umbilical arms,” Quinn said. “There are a few things that did receive more damage than expected, including some of our pneumatic lines. After launch, we lost our gaseous nitrogen supply, which delayed the flow of water that would have rinsed off some of the [Solid Rocket Booster] residue early. Because of that, we had some of our pneumatic lines get corroded.”
There was additional damage to the blast plates around the flame hole, which were damaged by heat and are currently being replaced.
Another area of concern was the Orion spacecraft’s heat shield. The team found that the heat shield had worn in a different way than models had predicted.
The heat shield is ablative, meaning it is designed and expected to erode somewhat during reentry into the atmosphere. “Part of that heating to 5,000 degrees Fahrenheit that you would encounter on a reentry is that you’re going to see a charring of that material,” Howard Hu, the manager of the Orion program, explained. “Kind of what you do when you barbecue.”
However, what was seen on the Orion’s heat shield was that some small pieces were coming off, rather than a general ablation. The team is now looking through sensor data and using visual inspection to understand this issue further.
Hu emphasized that the degradation of the heat shield was within acceptable limits. “We had a significant amount of margin left over,” he said. This margin is designed to allow for variations in the atmospheric environment that the spacecraft will pass through, while still keeping the crew inside safe from the heat.
We’re being very cautious to make sure we’re doing our due diligence,” Hu said. “Vigilance is very important for us when flying crew. We want to make sure we have significant margin to protect against the various uncertainties and variations you might experience when we reenter the atmosphere.”
NASA officials confirmed that, with a full review of the data underway, they are still targeting a November 2024 launch for Artemis II.
