Orion capsule returns to Earth after Artemis I flight around moon
Capsule carrying mannequins instead of astronauts concludes 25-day mission
The Orion spacecraft zoomed through Earth's atmosphere and splashed down in the Pacific Ocean on Sunday, the U.S. space agency confirmed, capping a 25-day voyage around the moon and back as part of NASA's first Artemis mission.
NASA's gumdrop-shaped capsule splashed down on time at 9:40 a.m. PT (12:40 p.m. ET) near Guadalupe Island, off the coast of Mexico's Baja California peninsula, after deploying various sets of manoeuvres to slow its return from space and dissipate heat around the spacecraft.
The incoming capsule hit the atmosphere at Mach 32, or 32 times the speed of sound, and endured re-entry temperatures of 2,760 degrees C shortly after hitting Earth's atmosphere for a 20-minute plunge to the ocean.
Re-entry marked the single most critical phase of Orion's journey, testing whether its newly designed heat shield would withstand atmospheric friction.
"It is our priority-one objective," NASA's Artemis I mission manager Mike Sarafin said at a briefing last week. "There is no arc-jet or aerothermal facility here on Earth capable of replicating hypersonic re-entry with a heat shield of this size."
The flight home also tested the advanced guidance and thruster systems used to steer the capsule from the moon to its proper re-entry point and through descent, maintaining the spacecraft at just the right angle to avoid burning up.
'Skip entry' for control
The heat, speed and forces exerted on Orion on its return from the moon exceeded those endured by spacecraft making more routine descents from the International Space Station or other flights from low-Earth orbit.
Orion employed a novel "skip entry" descent in which the capsule briefly dips into the top of the atmosphere, flies back out and re-enters — a braking manoeuvre that also provides more control in steering the vehicle closer to its intended splashdown target.
The capsule was upright and stable when it landed in the water, aided in the splashdown by three parachutes. A U.S. Navy ship quickly moved in to recover the spacecraft carrying a simulated crew of three mannequins wired with sensors.
Orion blasted off on Nov. 16 from the Kennedy Space Center at Cape Canaveral in Florida, atop NASA's towering next-generation Space Launch System (SLS), now the world's most powerful rocket and the biggest NASA has built since the Saturn V of the Apollo era.
The debut SLS-Orion voyage kicked off Apollo's successor program, Artemis, aimed at returning astronauts to the lunar surface this decade and establishing a sustainable base there as a stepping stone to future human exploration of Mars.
By coincidence, the return to Earth of Artemis I unfolded on the 50th anniversary of the Apollo 17 moon landing of Gene Cernan and Harrison Schmitt on Dec. 11, 1972. They were the last of 12 NASA astronauts to walk on the moon during a total of six Apollo missions starting in 1969.
The flight home also tested the advanced guidance and thruster systems used to steer the capsule from the moon to its proper re-entry point and through descent, maintaining the spacecraft at just the right angle to avoid burning up.
NASA officials have stressed the experimental nature of the Artemis I mission, marking the first launch of the Boeing Co.-built SLS and the first combined with Orion, which previously flew a brief two-orbit test launched on a smaller Delta IV rocket in 2014.
Though the capsule encountered some unexpected communication blackouts and an electrical issue during its voyage around the moon, NASA has given high marks to the performance of both SLS and Orion so far, boasting that they exceeded the U.S. space agency's expectations.
Next flight to include a crew
A crewed Artemis II flight around the moon and back could come as early as 2024 — carrying four astronauts, including a Canadian — followed within a few more years by the program's first lunar landing of astronauts, one of them a woman, with Artemis III.
Compared with Apollo, born of the Cold War-era U.S.-Soviet space race, Artemis is more science driven and broad-based, enlisting commercial partners such as Elon Musk's SpaceX and the space agencies of Europe, Canada and Japan.
It also marks a major turning point for NASA, redirecting its human spaceflight program beyond low-Earth orbit after decades focused on space shuttles and the ISS.