The Artemis 1 spacecraft is heading into flight Sunday to finish a historic mission

NASA’s Artemis 1 spacecraft concluded a 25-day journey around the moon, shutting its doors to Earth on Saturday, on track for a 25,000-mph return Sunday that will subject the uncrewed capsule to a hellish 5,000-degree inferno before crashing off Baja California. .

In an unexpected but symbolically rich coincidence, the end of the Artemis 1 mission, predicted at 12:39 p.m., will come 50 years to the day after the final Apollo moon landing in 1972.

Testing the Orion capsule’s Apollo-derived 16.5-foot-wide Avcoat heat shield is the top priority for the Artemis 1 mission, “and it’s our number one goal for a reason,” said Mike Saravin, mission manager.

“There is no arc jet or air thermal facility here on Earth capable of repeat entry at supersonic speed with a heat shield of this size,” he said. “It’s a completely new design for a heat shield, and it’s a piece of equipment that’s paramount to safety. It’s designed to protect the spacecraft and (future astronauts) … so the heat shield has to work.”

Launched November 16th In the first flight of NASA’s massive new Space Launch System rocket, an uncrewed Orion capsule was propelled from Earth’s orbit to the Moon to perform an exhaustive series of tests, putting the propulsion, navigation, power and computer systems through their paces in a deep space environment.

While the flight controllers encountered still unexplained glitches in their power system, the initial “burlesque” with star trackers and degraded performance from the phased array antenna and the Orion spacecraft and service module constructed by the European Space Agency Worked well in generalachieving nearly all of their major goals up to this point.

“We have collected an enormous amount of data characterizing system performance from the power system, propulsion, and GNC (steering, navigation, and control) and to date, the flight control team has correlated over 140 gigabytes of engineering data and imagery,” said Jim Jeffer, vehicle integration manager. Orion.

The team is already analyzing that data to “help not only understand the performance on Artemis 1, but also move forward on all subsequent missions,” he said.

If all goes well, NASA plans to follow up on the Artemis 1 mission by sending four astronauts around the moon on the program’s second flight — Artemis 2 — in 2024. The first moon landing will follow in the 2025-26 timeframe when NASA says the first will set foot. Introduce the next woman and man on the moon.

The uncrewed Artemis 1 capsule flew through half an orbit around the Moon and carried it farther from Earth — 268,563 miles — than any previous human-class spacecraft. Two critical launches of its main engine set up a low-altitude flyby of the lunar surface last Monday, which in turn set the rover on course for a landing on Sunday.

NASA originally planned to drop the ship west of San Diego, but anticipation of a cold front bringing higher winds and rougher seas prompted mission managers to move the landing site south about 350 miles. Splashdown is now expected south of Guadalupe Island about 200 miles west of Baja California.

The Orion spacecraft, which is traveling at 32 times the speed of sound, is approaching from approximately south, and is expected to re-enter the clear atmosphere at 400,000 feet, or about 76 miles, at 12:20 p.m.

NASA planners have created a unique “skip entry” profile that will cause Orion to skip through the top of the atmosphere like a flat stone skipping through calm waters. Orion will descend from 400,000 feet to about 200,000 feet in just two minutes, then rise again to about 295,000 feet before resuming a computer-guided fall to Earth.

Within a minute and a half of entry, atmospheric friction would generate temperatures through the heat shield of nearly 5,000 degrees Fahrenheit, enveloping the spacecraft in an electrically charged plasma that would block communications with flight controls for about five minutes.

After another two-and-a-half-minute communications pause during its second descent into the lower atmosphere, the spacecraft will continue to slow down as it approaches its target landing site, slowing to about 650 miles per hour, roughly the speed of sound, about 15 minutes after entry begins.

Finally, at an altitude of about 22,000 feet and a speed of about 280 miles per hour, small helicopter parachutes will deploy to stabilize the spacecraft. The ship’s main parachutes will deploy at about 5,000 feet, slowing Orion to 18 mph or so for a splash.

Projected mission duration: 25 days, 10 hours, 52 minutes, covering 1.4 million miles since the explosion on November 16.

NASA and Navy rescue crews aboard the USS Portland, an amphibious vessel, will stand within sight of splashing water, ready to secure the craft and tow it to the flooded “well deck.”

Once the deck hatches were closed, the water would be pumped out, leaving Orion on a dedicated stand, for heat shield protection, for the return trip to Naval Base San Diego.

But first, the recovery team will stand for up to two hours while engineers collect data on how the return heat is absorbed into the spacecraft and what, if any, effects it might have on the temperature of the crew cabin.

“We are well on our way to a fully successful mission with a few additional goals that we’ve achieved along the way,” Sarafin said. “And on entry day, we will achieve our first goal, which is to show the vehicle in conditions for a return to the Moon.”

William Harwood

Bill Harwood has covered the US space program full time since 1984, first as Cape Canaveral bureau chief for United Press International and now as a consultant for CBS News. He has covered 129 space shuttle missions, every interplanetary flight since the Voyager 2 flyby of Neptune and dozens of commercial and military launches. Based at the Kennedy Space Center in Florida, Harwood is a dedicated amateur astronomer and co-author of “Comm Check: The Final Flight of Shuttle Columbia.”