January 31, 2023

Artemis 1 back on Earth after near-flawless 25-day moon mission

NASA’s Orion spacecraft descends under three. orange and white main parachutes. Credit: NASA

NASA’s Orion spacecraft parachuted to a gentle splashdown in the Pacific Ocean Sunday west of Baja California, ending an unpiloted test flight to the moon that spanned 25-and-a-half days and 1.4 million miles, proving out a new rocket and capsule to carry astronauts back to Earth’s celestial companion.

“This is a defining day,” said NASA Administrator Bill Nelson. “It is one that marks new technology, a whole new breed of astronaut, a vision for the future that captures the DNA of particularly Americans, although we do this as an international venture. And that DNA is we are adventurers, we are explorers, we always have a frontier. And that frontier is now to continue exploring the heavens.”‘

“This is what mission success looks like, folks,” said Mike Sarafin, NASA’s Artemis 1 mission manager. “This was a challenging mission.”

The roundtrip journey to the moon began Nov. 16 with the blastoff of NASA’s 322-foot-tall (98-meter) Space Launch System moon rocket from Kennedy Space Center in Florida. On Sunday, the Orion crew capsule streaked back into Earth’s atmosphere at more than 24,400 mph (33,370 kilometers per hour), some 32 times the speed of sound, as temperatures on the moonship’s ablative Avcoat heat shield built up to 5,000 degrees Fahrenheit (2,760 degrees Celsius).

Communications signals from the spacecraft were interrupted by the plasma sheath around the capsule as it performed the first of two dips into the atmosphere during a “skip re-entry” to bleed off speed, reduce the g-loads, and provide a lower heating rate for the capsule’s thermal protection system. The skip re-entry also allowed the Orion spacecraft to target a more precise splashdown zone closer to recovery forces.

The capsule descended just below 200,000 feet (61 kilometers), then climbed again to roughly 294,000 feet (nearly 90 kilometers) before falling back into the atmosphere for the final part of the re-entry. The Orion capsule jettisoned a cover from its parachute compartment, then released drogue chutes and three main parachutes to slow to some 20 mph (32 kilometers per hour) for splashdown at 12:40 p.m. EST (1740 GMT).

The splashdown occurred 50 years to the day after NASA’s Apollo 17 mission landed in a lunar valley called Taurus-Littrow for a three-day stay. Astronauts haven’t visited the moon since then, but NASA’s Artemis program — named for the sister of Apollo in Greek mythology — aims to resume human exploration of the moon later this decade.

“From Tranquility Base to Taurus-Littrow to the tranquil waters of the Pacific, the latest chapter of NASA’s journey to the moon comes to a close — Orion back on Earth,” said Rob Navias, NASA’s commentator for the re-entry and splashdown.

“Today, the two the main things that had to happen were the heat shield had to work, and it did beautifully,” Nelson said. “And then the parachutes had to work, and they did as well.”

The Orion spacecraft splashed down 2.1 nautical miles from its targeted landing site, well within the 5 nautical mile radius that was the requirement, according to Howard Hu, NASA’s Orion program manager.

Mission controllers at NASA’s Johnson Space Center in Houston monitored telemetry data from the Orion spacecraft for a couple hours after splashdown, measuring the behavior of the capsule’s thermal control system after the scorching hot re-entry. Then a joint U.S. Navy, NASA, and contractor team on the USS Portland recovery ship attached a collar to the 16.5-foot-diameter (5-meter) capsule and towed it into the flooded well deck of the vessel.

After positioning the capsule over a cradle, the recovery team drained water from the well deck and the USS Portland set a course for San Diego, where it could arrive as soon as Tuesday. The spacecraft will be offloaded from the Navy ship later this week and trucked across the country back to Kennedy Space Center for inspections and post-flight servicing, including the draining of leftover toxic propellants and extraction of data recorders and science payloads.

By all accounts, the Artemis 1 test flight was a success, demonstrating the SLS moon rocket and Orion spacecraft that NASA and industry teams have spent more than a decade designing, developing, and building.

“We set priorities,” said Mike Sarafin, NASA’s Artemis 1 mission manager. “Priority 1: Demonstrate the vehicle at re-entry conditions. We successful demonstrated that today. Priority 2: Demonstrate the vehicle in the flight environment. We’ve successfully demonstrated that over the course of a 25-day test flight.

“We now have a foundational deep space transportation system,” Sarafin said. “While we haven’t looked at al the data that we’ve acquired, we will do that over the coming days and weeks and fully understand and appreciate the margins that are there.”

There were only a few unexpected events, or “funnies,” on the Artemis 1 mission. One involved degraded performance from a phased array antenna on the Orion spacecraft. engineers also saw unexpected data from the capsule’s star trackers, cameras used to help the spacecraft determine its position in space. NASA officials believe the star tracker issue was not a real problem after better understanding how the cameras were working in space.

With the Artemis 1 mission going well, NASA officials added 20 bonus objectives to the flight on top of the 124 test objectives NASA engineers identified before the launch.

“The biggest surprise to me was a positive one, and it was simply that the first time flight of a brand new rocket, a brand new spacecraft … went as smoothly as it did,” Sarafin said. “And I think that’s a testament to the level of preparation, the quality of workmanship, and just the overall level of tests and the effort put into getting this mission ready to fly.”

NASA’s Orion spacecraft floats in the Pacific Ocean off the coast of Baja California following splashdown Sunday. Credit: NASA

While there were no humans on-board Artemis 1, the Orion spacecraft carried three instrumented mannequins inside its pressurized cabin to gather data on accelerations, vibrations, and radiation on the flight to the moon and back. There was also a biological experiment inside the cockpit to help scientists study how the deep space environment, including elevated levels of ionizing radiation, affects organisms like plant seeds, fungi, yeast, and algae.

The crew cabin in the Artemis 1 capsule is kept pressurized at a comfortable temperature, but the Orion spacecraft’s full life support system will fly for the first time on Artemis 2, the next flight of the SLS moon rocket and Orion crew capsule. Four astronauts will fly around the far side of the moon and back to Earth on Artemis 2, currently scheduled for the second half of 2024.

Engineers on Earth also uplinked messages and commands to a voice-activated crew interface technology demonstration payload named Callisto inside the pressurized crew module. A stuffed Snoopy toy was also on-board for the flight to the moon.

NASA flew a stripped down Orion crew capsule in space once before in 2014, when the spacecraft launched into a high-altitude orbit around Earth for a four-hour test flight. Artemis 1 was the first time an Orion spacecraft flew with its European-built service module, which supplied power and propellants to the moonship. The European service module exceeded design specifications, producing more power and consuming less fuel than expected on the 25-day test flight.

The European service module was jettisoned from the Orion crew module just before it plunged into the atmosphere Sunday. The service module was designed to burn up on re-entry.

The Orion spacecraft is designed to accommodate a crew of four astronauts in deep space for up to 21 days, and can fly longer missions when docked to Gateway mini-space station NASA and its international partners plan to build in orbit around the moon. The Orion crew module, where astronauts will live during lunar expeditions, was built by Lockheed Martin.

With the successful return of Artemis 1, NASA’s exploration program will turn its attention to Artemis 2 and later missions. The Artemis program’s first lunar landing mission is slated for Artemis 3, no earlier than 2025. NASA’s inspector general has reported the Artemis 3 landing mission is likely to be delayed beyond 2025 as the agency awaits the completion and certification of a commercial human-rated lander from SpaceX and new spacesuits for lunar surface sorties.

NASA plans an upgrade to the upper stage of the SLS moon rocket for the Artemis 4 mission and subsequent flights. That will require the construction of a new mobile launch platform at Kennedy Space Center, a project plagued by delays and cost overruns that threaten to delay its ability to support a launch until late 2027.

NASA’s Orion spacecraft was secured in the well deck of the U.S. Navy recovery ship USS Portland. Credit: NASA

Eventually, NASA wants to establish a cadence of one Artemis mission per year to build the Gateway mini-space station in lunar orbit and permanent infrastructure on the moon’s surface.

“This isn’t just one flight and we’e done,” said Jim Free, associate administrator of NASA’s exploration systems mission development programs. “We are on a path to getting that base on the moon, and getting the understanding we need to go on to Mars.”

The program hasn’t been cheap. The SLS moon rocket has cost more than $22 billion to develop over the past decade, through the work of prime contractors Boeing, Northrop Grumman, and Aerojet Rocketdyne. Another $5.4 billion in the same period went toward readying Kennedy Space Center’s ground infrastructure for SLS and Orion missions.

NASA awarded Lockheed Martin the contract to develop the Orion spacecraft in 2006 under the umbrella of the agency’s Constellation moon program, which was canceled in 2010.

NASA kept the Orion program alive through two major restructurings of the agency’s deep space exploration efforts, first during the Obama administration, when Congress and the White House agreed to pivot NASA’s focus to a human mission to Mars, with an interim crewed expedition to an asteroid.

The Trump administration shifted NASA’s exploration program back to the moon, and the Artemis program was born in 2019, inheriting the SLS and Orion development work already well underway.

NASA committed $14.2 billion to develop the Orion spacecraft from 2012 through the end of the last fiscal year Sept. 30, plus an additional $6.3 billion spent on the program in the prior decade under the Constellation program. That comes to $20.5 billion over the course of a decade-and-a-half of work.

The SLS moon rocket performed flawlessly, NASA officials said, sending the Orion capsule on a five-day track toward the moon, where it zoomed about 80 miles (130 kilometers) from the surface Nov. 21. The close flyby used lunar gravity to swing the Orion spacecraft into a distant retrograde orbit, or DRO, some 50,000 miles (80,000 kilometers) from the moon.

Another main engine burn Nov. 25 placed the Orion spacecraft into the DRO, so named because it is not a low-altitude orbit like the Apollo capsules of the 1960s and 1970s flew in, and because Orion is moving around the moon in the opposite direction the moon travels around Earth.

Mission planners chose the orbit for the Artemis 1 mission for several reasons. First, the Orion spacecraft’s propulsion system does not have the capability to steer the capsule into a low-altitude orbit around the moon as the Apollo missions did. And the DRO is stable because it is near the balance point between the pull of gravity from Earth and the moon, reducing the fuel Orion needs to burn to maintain its orbit.

A camera on one of the Orion spacecraft’s solar array wings captured this view of the crew module Monday, Nov. 28, with the Earth and the moon in the background. Credit: NASA

The Orion spacecraft spent about six days in the distant retrograde orbit performing tests and checkouts, long enough to complete one-half of a lap around the moon. On Nov. 26, the capsule broke the distance record for a spacecraft designed to carry humans into space and return them to Earth, according to NASA.

The record was previously set on NASA’s Apollo 13 mission, which reached a distance of 248,655 miles (400,171 kilometers) from Earth when it looped around the far side of the moon with a three-man crew in 1970. Apollo 13’s moon landing was aborted when one of its oxygen tanks exploded on outbound journey from Earth, and the spacecraft steered onto a “free return” trajectory that took it farther from Earth than any of the other Apollo missions.

The Orion spacecraft reached its greatest distance from Earth on Monday, Nov. 28, at more than 268,500 miles (432,000 kilometers).

The Orion main engine, a leftover orbital maneuvering system engine from the space shuttle program, fired again Dec. 1 to depart the distant retrograde orbit. The moon’s gravity pulled the Orion spacecraft toward a high-speed flyby just 79 miles (127 kilometers) from the surface on Monday, Dec. 5. The Orion main engine fired for the final time on the Artemis 1 mission to aim Orion toward its splashdown point in the Pacific Ocean.

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