Artemis II live: NASA prepares for risky ‘13 minutes’ as astronauts ‘halfway’ back home – UK Times

Here, experts lay out just how intense and extreme the Artemis II crew’s re-entry will be.

Here’s a full preview of the main event of today – the astronauts’ re-entry and splash down.

Coming back down is hot. And astronauts are essentially racing that process. Here, Chris Hadfield – a Canadian astronaut who has flown a number of space missions – explains how that feels on the inside.

As the Artemis astronauts make their way back to earth, a planetary entry experts says this critical phase of the journey will be one of the most dangerous.

Dr Chris James, who specialises in hypersonic aerothermodynamics at the University of Queensland, said: “The most dangerous moment will be the high-speed, hypersonic re-entry that occurs as the craft is travelling through the upper atmosphere. This is the riskiest point for several reasons.

“Firstly, it’s when the heating and the forces hitting the craft itself are at their maximum, due to aerodynamic drag slowing the craft from hypersonic speeds of around 11 km per second (greater than Mach 30!).

“Secondly, this is also a scary moment because the gas surrounding the craft is heated up so much that it becomes an electrically conductive plasma – which blocks communication between the spacecraft and the outside world. This means the astronauts are unable to talk to anybody back on Earth for that short period of time.”

When the astronauts first reach earth’s atmosphere, they will be experiencing fairly high g-forces, and get “the hell shaken out of them”, he said.

He believes one of the scariest parts will be the communications blackout blocking radio communications, which means they will be completely alone during the harshest parts of the trajectory.

Along with four astronauts, NASA also sent chips of bone marrow grown from the crew’s own cells to space.

Researchers put the USB-sized “organ chips” aboard the Orion spacecraft, as part of a science experiment they hope will help reveal how different space stressors affect tissue before sending the first humans to mars.

The investigation will use the devices to study the effects of increased radiation and microgravity on human health.

Lisa Carnell, from NASA’s biological and physical sciences division, said: “For NASA, organ chips could provide vital data for protecting astronaut health on deep space missions.”

The chips, which were developed at Harvard, contain tiny channels lined with living cells that replicate the function of human bone marrow.

A matching set of these chips has stayed on Earth to give researchers a controlled comparison.

Astronaut Christina Koch said she has fulfilled her childhood dream, as she reflects on how she ended up in space.

“I recently found some photos of myself on a family vacation at Kennedy Space Centre, and were we posing with in front of the Saturn V Rocket.

“If I could have told that little girl who took home a picture of Earthrise, and hung it in her room, that she would eventually launch from that same place, to see that same view, I’m pretty sure she would not believe it.

“But even though I still can’t believe it, and she certainly wouldn’t believe it, she chased that dream, and it ended up happening.

“It’s such an honour to hear that we’ve inspire, that’s truly one of the top things that we ever wanted to do.”

The four Artemis II astronauts, returning from the world’s first crewed moon voyage in over half a century, hurtled back toward Earth on Friday aboard their gumdrop-shaped Orion spacecraft, headed for a splashdown in the Pacific Ocean off Southern California.

The finale to NASA’s celebrated 10-day mission was expected to begin with separation of Orion’s crew capsule from ⁠its service module.

This will be followed by a fiery re-entry through Earth’s atmosphere and a six-minute radio blackout before the capsule parachutes into the sea.

If all goes well, astronauts Reid Wiseman, Victor Glover and Christina Koch, along with Canadian astronaut Jeremy Hansen, will end up bobbing safely in the ocean aboard their Orion capsule, dubbed Integrity, shortly after 0000 GMT off the coast of San Diego.

The Orion capsule’s exterior could reach temperatures of over 2,760C as it plummets through the Earth’s atmosphere during the re-entry sequence.

Experts are calling this the riskiest part of the mission, partly due to what was found from the previous Artemis I test mission to the Moon, in which the uncrewed capsule returned with concerning pockmarks and cracking.

The same heat shield has been used in Artemis II, and if it becomes damaged in a particular way, it could be catastrophic.

When Artemis II astronaut Victor Glover was asked what he looked forward to, he said it was the splashdown.

“I’ll be honest and say, I’ve actually been thinking about entry since April 3, 2023, when we got assigned to this mission,” Glover said.

NASA mission managers say they understand the heat shield’s limitations and how to protect the crew with a different trajectory for splashdown compared to the Artemis I mission.

The 2022 test flight used a “skip” reentry in which the capsule briefly plunged into the atmosphere before raising its altitude again for a second plunge.

But the Artemis II mission will attempt a “loft” re-entry to create more favourable heating conditions, according to NASA Flight DirectorRick Henfling.

This is expected to limit, but not eliminate the cracking on the heat shield observed in the uncrewed mission.

NASA expects that even if the heat shield does not perform optimally, astronauts will get home safe.

“There’s no doubt about it: This is not the heat shield that NASA would want to give its astronauts,” former NASA astronaut Danny Olivas told CNN earlier this year.