The farthest journey in human history concluded Friday evening when NASA’s Artemis II astronauts returned to Earth after a flight around the moon. The crew’s Orion space capsule named Integrity splashed down in the Pacific Ocean off the coast of San Diego shortly after 5 pm Pacific Time, marking the end of a 10-day, more than 695,000-mile voyage beyond the far side of the moon and back.
The four-person crew of Artemis II—commander Reid Wiseman, pilot Victor Glover, mission specialist Christina Koch, and mission-specialist Jeremy Hansen—traveled a greater distance from Earth than anyone has before, reaching 252,756 miles from our home planet.
“We most importantly choose this moment to challenge this generation and the next to make sure this record is not long-lived,” said Canadian astronaut Hansen as the crew passed the previous record of 248,655 miles set during Apollo 13.
Integrity began its fiery descent when the spacecraft hit Earth’s atmosphere at about 24,000 miles per hour, entering a communication blackout and decelerating from friction as its heat shield reached temperatures of roughly 3,000 degrees Fahrenheit. The plan was for the capsule to deploy two drogue parachutes at an altitude of about 22,000 feet, slowing it to about 200 miles per hour, then deploy pilot chutes pulling the three main parachutes at roughly 6,000 feet. This would further slow the spacecraft to around 20 miles per hour before it splashed into the ocean.
During their mission, the Artemis II crew saw things that no human has seen before. Flying higher above the lunar surface than the Apollo missions, the astronauts were the first people to see the entire disk of the moon’s far side. They also witnessed a solar eclipse from the vicinity of the moon as the sun slipped behind the lunar disk and illuminated it from behind.
“Humans probably have not evolved to see what we are seeing,” said NASA astronaut Glover during the eclipse. He and the rest of the crew described a halo of light surrounding the moon while one side of the lunar surface was bathed in earthshine. Venus, Mars, and Saturn shone among the stars. “It is truly hard to describe. It is amazing.”
Artemis II began on April 1 when the crew launched from NASA’s Kennedy Space Center in Florida atop the 322-foot-tall Space Launch System rocket, the most powerful vehicle to ever carry humans. After conducting multiple altitude-raising engine burns and testing the manual controls of the spacecraft, the crew proceeded with the engine firing known as translunar injection on day two of the mission, which sent them on a trajectory to the moon.
For the next three days, the crew tested the Orion spacecraft’s systems, practiced putting on their spaceflight suits, conducted additional course correction burns, manually flew the Orion capsule again, and prepared for the lunar flyby around the far side of the moon. They also had trouble venting wastewater from the Orion capsule’s toilet into space.
“We definitely have to fix some of the plumbing,” NASA administrator Jared Isaacman said during a conversation with the crew.
At 12:41 am Eastern Time on April 6, Artemis II entered the lunar sphere of influence, where the moon’s gravity overcomes that of Earth. That day, the crew made their closest approach to the moon, flying to about 4,000 miles above the lunar surface. During the lunar flyby, the crew communicated with a team of scientists on the ground, both before and after a roughly 40-minute communication blackout on the far side, to describe geologic features such as craters and canyons.
Just after breaking the distance record, the crew proposed names for two young, unnamed craters on the moon. The first they called Integrity, after their spacecraft, and the second they named Carroll, in honor of commander Reid Wiseman’s wife, who died of cancer in 2020.
“It's a bright spot on the moon, and we would like to call it Carroll,” Hansen radioed down while the emotional crew embraced each other, fighting back tears.
From their perch near the moon, the astronauts could see the three-dimensional topography of the lunar landscape in a way that is not possible with photographs, truly getting a sense of the dynamic, rugged surface. At the lunar south pole, where NASA hopes to land a future Artemis mission as soon as 2028, the astronauts described a steep and intimidating landscape. “It seems to be more jagged and a more challenging place to find a place to land and to traverse in the south, all around the south pole,” Glover said.
They could clearly see differences in brightness on the lunar surface, particularly in the center of young craters where whitish minerals had been freshly excavated by an impact. “What it really looks like is like a lampshade with tiny pinprick holes and the light shining through,” NASA astronaut Koch said of crater centers on the lunar surface. “They are so bright compared to the rest of the moon.”
The crew members also saw colors on the moon that are not visible from Earth, describing brownish patches all around the moon and a greenish tint on Aristarchus Plateau.
“My suspicion right now is it's volcanic terrain,” says Trevor Graff, a NASA science officer who communicated with the astronauts during the mission. “Certain minerals have greenish hues to them … We collected green glass during the Apollo mission that was indicative of fire fountaining from volcanoes.”
During the eclipse, the astronauts were able to see multiple impact flashes as small meteorites hit the moon. Developing a better understanding of the frequency of these impacts will be crucial to establishing a future base on the moon, a stated goal of NASA’s Artemis program.
“Thousands of tons per year of extraterrestrial material comes to Earth, and most of it is teeny tiny particles that get slowed down way high in the atmosphere,” says Laurie Leshin, a professor at Arizona State University and former director of NASA’s Jet Propulsion Laboratory. “But on the moon, there's nothing there to slow them down, so even the small stuff whacks into the moon with quite a lot of force.”
As the astronauts flew near the moon, they took photos, made audio recordings of their scientific conversations, and sketched what they saw to help researchers on the ground identify the most intriguing targets for further study. Much of this data was beamed back down to Earth using a new laser communications system that transmits up to 260 megabits per second, much faster than previous radio systems.
“Now we can direct orbiters to those regions that they specifically called out where they saw these colors, and we can go and collect more data to understand what they really saw,” says Juliane Gross, a member of NASA’s Artemis science team.
After the lunar flyby, the crew began its return flight to Earth, leaving the moon behind. They continued to test the spacecraft’s systems, tried on specialized garments to help with blood circulation, exercised using a flywheel fitness machine, and conducted the first radio transmission between a deep space vessel and the crew currently aboard the International Space Station.
In the final days, the astronauts prepared the capsule for entry, descent, and landing. Orion separated from the European Service Module, which provided engine propulsion, solar power, and life support throughout the mission, about 30 minutes before hitting Earth’s atmosphere.
In addition to the trove of scientific data about the moon, the Artemis II astronauts returned with a new perspective on Earth, one that they hope to share with the rest of the world.
“What we really hoped in our soul,” commander Wiseman said, “is that we could for just a moment have the world pause and remember that this is a beautiful planet and a very special place in our universe.”
此内容由惯性聚合(RSS阅读器)自动聚合整理，仅供阅读参考。 原文来自 — 版权归原作者所有。