WASHINGTON — NASA’s Orion spacecraft is on the home stretch of the Artemis 1 uncrewed test flight as the agency prepares for the vehicle’s ultimate test: reentry and splashdown in the Pacific Ocean.
Project officials said in a Dec. 8 briefing that all was well with the final stages of the Artemis 1 mission, with the 25.5-day mission expected to conclude with a splashdown in the Pacific around 12:40 p.m. Eastern time, December 11.
One change in the final stages of the mission is the location of the splashdown. Judd Frieling, flight director at NASA’s Johnson Space Center, said mission officials decided to move the splashdown from its original location off the coast of San Diego, California, about 550 kilometers upstream, to the south. The spacecraft will instead crash near Isla Guadalupe, west of Baja California.
He said the main landing site as well as the northern escape site were “prohibited” due to weather conditions as a cold front was expected to pass through the area at the time of the splash. Artemis 1 mission manager Mike Sarafin later said concerns about the spacecraft flying in light rain, as well as winds and waves that could hamper recovery efforts, led them to move the area landing.
“There was an area of uncertainty for the weather forecast,” Sarafin said, with conditions just on the edge of what would be acceptable, “and we moved south of the area of uncertainty.”
Changing the landing location will not affect recovery operations. The recovery team, on the US Navy ship USS Portland, will arrive at the landing site at least 24 hours in advance to collect weather data to support re-entry, said Melissa Jones, director of the NASA landing and recovery mission.
After the capsule splashes down, it will stay in the water for two hours to perform a “soak” test to see how the spacecraft handles the heat pulse of re-entry. The recovery team, supported by small boats and helicopters, will then tow the capsule into the well deck of the USS Portland, placing it in a cradle and then emptying the deck.
Testing Orion by reentry at lunar return speeds of around 40,000 kilometers per hour is the mission’s top priority. “There is no arc jet or aerothermal facility here on Earth to replicate hypersonic reentry with a heat shield of this size,” Sarafin said. “This is essential safety equipment. It is designed to protect the spacecraft and passengers, astronauts on board. So the heat shield must work.
Orion will also use a “jump” re-entry, where the capsule re-enters and descends to an altitude of approximately 60 kilometers, then climbs to 90 kilometers before descending again to crash. The maneuver is designed to reduce g-loads on the spacecraft and its occupants and also provides more flexibility in choosing a landing site.
Recovering Orion after splashdown is another top priority. This involves both studying the spacecraft after its flight as well as recovering several avionics units on the spacecraft which will be refurbished and flown again on Artemis 2.
Of Orion’s other 124 test targets during the mission, Sarafin said more than 30% were complete and another 37.5% were in progress, in some cases collecting data until re-entry. The rest, he said, mostly involves re-entry, splash-down and recovery-related goals, along with a few post-flight goals, such as monitoring the spacecraft for corrosion due to exposure to salt water.
The absence of major problems during the mission allowed NASA to add 14 objectives, 10 of which are complete, he said. The other four are in progress or have not yet started their work.
While the spacecraft was largely healthy, officials said they were still trying to figure out a problem with the spacecraft’s power system where devices called latching current limiters were opening without they are ordered to do so. This happened 17 times during the Artemis 1 mission, Sarafin said.
“That’s the only thing the team is trying to figure out. We still have to find a root cause for that,” he said. Engineers are also monitoring degraded performance over the past few days from a phased array antenna on the spacecraft that caused communication interruptions.