ARTEMIS 1 COMPLETES HISTORIC MOON MISSION
The uncrewed flight paves the way for NASA to return humans to the Moon.
NASA has finally taken its first small step toward sending humans back to the Moon.
Over the course of a 25-day flight, the uncrewed Artemis 1 mission launched aboard NASA’s brand-new Space Launch System (SLS), looped around the Moon twice thanks to the European-built Service Module, and splashed down with the Orion capsule off Mexico’s Baja California coast on Dec. 11 — the 50th anniversary of the Apollo 17 Moon landing.
In the runup to the launch, NASA officials had emphasized that the mission was a test flight. “We are stressing Orion beyond what it was designed for,” said Bob Cabana, NASA’s associate administrator, at a briefing. But Artemis 1 passed with flying colors, proving that the hardware meant to fly humans to the Moon is up to the task.
TRY, TRY AGAIN
It took some doing, though, just to get SLS off the ground.
After a series of tests throughout the summer and fall, the first launch attempt on Aug. 29 ended in a scrub. Among other glitches, one of the core stage’s main engines failed to cool to the temperature required for launch. (Foul weather would have stalled the attempt anyway.)
The rocket’s second launch attempt Sept. 3 was scrubbed when a leak sprung while loading SLS’s supercooled liquid hydrogen fuel — possibly caused by a mistaken command that overpressurized the system. SLS remained at the Kennedy Space Center’s Launch Pad 39B while NASA attempted a fix.
NASA finally solved the issue ahead of a planned Sept. 27 launch window. Then came Hurricane
Ian, which forced NASA to send the rocket back to the safety of the Vehicle Assembly Building.
In October, NASA began aiming for a Nov. 14 launch. The rocket was rolled back to the pad, only for Hurricane Nicole to arrive shortly after. This time, though, the rocket stayed outside, and the launch window was pushed to the early morning hours of Nov. 16.
There were still hiccups: A small core-stage hydrogen leak forced a trio of technicians to go to the pad to tighten a valve on the mobile launcher. And a radar site that monitored the eastern launch range went dark due to a faulty ethernet switch that had to be replaced.
At 1:33 a.m. EST, NASA announced “no constraints” to launch and the countdown resumed. Six seconds before liftoff, the four core-stage liquid fuel engines started in rapid-fire succession.
As the countdown hit zero, SLS’s solid rocket boosters ignited.
Artemis 1 lifted off into Florida’s earlymorning sky Nov. 16 at 1:47 a.m. EST as the Last Quarter Moon was rising over the Space Coast. Witnesses reported that they teared up, cheered, and felt the ground shake.
Two minutes after liftoff, the solid rocket boosters were jettisoned, looking like massive fireworks.
The core-stage main engine cutoff took place eight minutes into the flight at an altitude of about
100 miles (162 kilometers) before separating from the second stage, called the Interim Cryogenic Propulsion Stage (ICPS), which lifted the craft to orbit.
Just over two hours into the flight, the ICPS lit its engine again for translunar injection, a nearly 18-minute burn that flung Orion from 17,500 to 22,600 mph (28,000 to 36,400 km/h) on toward the Moon. The ICPS was then jettisoned, though its role in the mission wasn’t over: As it coasted to the Moon, the ICPS released a flotilla of 10 small satellites called cubesats, each with its own scientific objective.
A LUNAR TESTING GROUND
Artemis 1 began its lunar encounter by carrying out a flyby of the Moon Nov. 21, swooping as low as 81 miles (130 km) above the pockmarked landscape. The European Service Module’s engine fired during the flyby, slinging the craft into a high, looping trajectory. Four days later, Orion reached its apolune of more than 57,000 miles above the Moon, and performed another burn to enter a distant retrograde orbit (DRO). During this phase of the flight, the capsule set a record for the farthest a human-rated craft has ever flown from Earth, some 268,563 miles (432,210 km).
After performing half an orbit around the lunar farside, Artemis 1 again fired its engine to exit DRO and drop toward the Moon for another powered flyby — this time, to fling it back home.
Orion raced toward Earth at around 25,000 mph (40,000 km/h), skipping once across the top of the atmosphere to achieve an optimal reentry trajectory. Three parachutes gracefully slowed the capsule to about 20 mph (32 km/h) for a splashdown at 9:40 a.m PST, within sight of the USS Portland.
In a NASA statement, Artemis 1 Mission Manager Mike Sarafin said that Orion’s deep-space performance had “exceeded our expectations,” and the mission “demonstrated that Orion can withstand the extreme conditions of returning through Earth’s atmosphere from lunar velocities.”
NASA plans to launch Artemis 2 in 2024, carrying humans to lunar orbit for the first time in a half-century. And the crew of Artemis 3, which is scheduled for 2025, will alight on the lunar surface — including the first woman and first person of color to walk on the Moon.
Following the successful splashdown of Artemis 1, NASA Administrator
Bill Nelson said: “It’s historic because we are now going back into space, into deep space, with a new generation. We are adventurers, we are explorers, we always have a frontier; and that frontier is now to continue exploring the heavens.”