Artemis 1 mission reaches halfway point
WASHINGTON — As the Artemis 1 mission reaches the halfway mark, NASA managers are adding additional test objectives for the Orion spacecraft to prepare for the vehicle’s first crewed flight.
At a Nov. 28 briefing, agency officials said they continued to be pleased by the performance of the uncrewed Orion spacecraft as it orbits the moon in the middle of the 25.5-day Artemis 1 mission. Controllers have dealt with only minor issues during the mission, none of which “are of consequence,” said Mike Sarafin, NASA Artemis 1 mission manager.
Because of that performance, NASA is adding seven new objectives to test the thermal environment of the spacecraft and its propulsion system during the mission. “We’re going to try and expand the thermal environment,” said flight director Rick LaBrode.
Orion normally flies in a “tail to sun” orientation with the aft section of the spacecraft pointed towards the sun for both thermal stability and power generation, but can deviate by up to 20 degrees in pitch and yaw. “What we’re doing is characterizing the corners of the box,” with the new test objectives, said Sarafin, as well as a requirement that, if the spacecraft is out of that orientation for more than three hours, it needs to return to its regular orientation for 10 hours for “thermal recovery” before using any thrusters.
“That is consistent with a test flight. We want to do envelope expansion and validate our models,” he said. “The halfway point in this mission affords us an opportunity to step back and look at what our margins are and where we could be a little smarter to buy down risk and understand the spacecraft’s performance for crewed flight on the very next mission.”
Those seven new objectives are on top of the 124 that Artemis 1 had for testing the performance of the Orion spacecraft. Sarafin said 25% of those objectives are now complete, with half of the rest in progress. Many of the remaining objectives, he said, are tied to events at the end of the mission, including reentry and splashdown.
Engineers have concluded an investigation into one issue Orion had suffered with random access memory in its star trackers. “We essentially concluded that the hardware is performing as expected and that this is a byproduct of the flight environment,” he said.
LaBrode said a 47-minute unexpected loss of communications with Orion early Nov. 23 was a configuration issue involving the Deep Space Network. Controllers had worked to increase bandwidth from Orion, which has enabled the spacecraft to stream live video. “It was simply a misconfiguration at the Deep Space Network, where they were set up for a data rate that the vehicle was not set up for,” he said.
While the performance of Orion is buying down overall risk ahead of the Artemis 2 crewed mission, Sarafin said that some won’t be addressed until Orion returns for a Dec. 11 reentry and splashdown off the California coast. The mission’s highest priority is to test the performance of the spacecraft when reentering at lunar return speeds, while another top priority is to recover the spacecraft after splashdown, including components like avionics units that will be reflown on Artemis 2.
“If you’re looking at our top ten risk drivers,” he said, “some of them have been retired, some are still in play, and some won’t be realized, for good or bad, until we get to entry, descent and splashdown day.”