After several false starts, NASA finally launched its Artemis I mission in November last year. The main purpose of the mission was to test new hardware such as the Space Launch System (SLS) rocket and Orion spacecraft ahead of the manned Artemis II mission.
Artemis II will be the first crewed launch to use the new system and is currently scheduled for next year. This mission will launch four astronauts into lunar orbit, making it the first crewed mission to emerge from low Earth orbit since 1972. It will be followed by Artemis III, which aims to land a crew on the lunar surface and in 2025.
However, a crewed launch will require some of the hardware used in Artemis I to be refreshed. At a press conference this week, NASA officials shared more information about what had been learned from the launch of Artemis I and what would be updated for Artemis II.
Artemis II will be the first crewed launch to use the new system and is currently scheduled for next year
“Every time you fly something new for the first time, you learn something, and this is also the case with Artemis I,” said Shawn Quinn, manager of the Exploration Ground Systems program.
The first area to work on is the mobile launcher, which is the structure that houses the missile while 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 the firing engines blew the doors off two of the elevators in the mobile launcher. One of these elevators has now been repaired and there are plans to harden the second to prepare it 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 took more damage than expected, including some of our pneumatic lines. After launch, we lost our supply of gaseous nitrogen, which slowed down the water flow that filled some of the spacecraft [Solid Rocket Booster] residue early. As a result, some of our pneumatic lines became corroded.”
“When you fly something new for the first time, you learn something, and that’s also the case with Artemis I.”
There was additional damage to the blast plates around the flame hole, which were damaged by heat and are currently being replaced.
Another concern was the Orion spacecraft’s heat shield. The team found that the heat shield had worn out in a different way than models had predicted.
The heat shield is ablative, meaning it is designed and expected to erode slightly during reentry. “Part of that 5,000-degree Fahrenheit warming that you’d see on a reentry is that you’re going to see a charring of that material,” Howard Hu, the manager of the Orion program, explained. “A bit of what you do when you barbecue.”
However, what could be seen on the Orion’s heat shield was some small pieces coming off, rather than a general ablation. The team is now reviewing sensor data and using visual inspection to further understand this issue.
Hu stressed that the degradation of the heat shield was within acceptable limits. “We still had a decent margin left,” he said. This margin is designed to allow for variations in the atmospheric environment through which the spacecraft passes, while keeping the crew inside protected from the heat.
Another concern was the Orion spacecraft’s heat shield
“We are very careful to make sure we do our due diligence,” Hu said. “Vigilance is very important to us when flying with crew. We want to make sure we have a significant margin to protect against the various uncertainties and variations you could experience when we re-enter 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.