On Monday, NASA’s Orion spacecraft reached its farthest distance from Earth, clocking in at 268,563 miles away from our planet. This marks the halfway point of the 25.5-day Artemis I mission, and the spacecraft will now continue its orbit around the Moon before heading back toward Earth.
“Artemis I has had extraordinary success and has completed a series of history-making events,” NASA administrator Bill Nelson said in a press conference, pointing out that Orion was the first spacecraft designed to carry humans to enter a distant retrograde lunar orbit and that it has surpassed the record for the furthest distance traveled away from Earth by a human-rated spacecraft.
During Orion’s orbit around the Moon, which will last about a week, it is collecting data on the conditions human astronauts can expect to experience on future Artemis missions. Of particular concern is space radiation, which astronauts will be exposed to once they leave Earth’s protective magnetosphere.
Orion is carrying one mannequin and two torsos that are filled with sensors to detect the levels of radiation they are exposed to. The mannequin (or, if we must, the “Moonikin”) is named after Arturo Campos, the NASA engineer who was instrumental in getting the Apollo 13 crew home following the explosion in the spacecraft in 1970. The mannequin is occupying the commander’s seat in the spacecraft and is weighted to simulate a human being. It is also wearing the same spacesuit that future Artemis astronauts will wear, and the seat has sensors to detect acceleration and vibration to give an idea of what the ride will be like during launch and reentry.
The two torsos on the flight are part of an experiment into radiation protection measures called the Matroshka AstroRad Radiation Experiment (MARE). Named Helga and Zohar, they are designed to mimic the body composition of an adult man and woman. Embedded with the materials are radiation detectors to see which particular organs and areas of the body will be exposed to the most radiation. One of the torsos, Zohar, will be wearing a radiation shielding vest called the AstroRad, which is designed to protect the most critical organs but still enable astronauts to move freely as they perform their duties. Results from both torsos will be compared to see how effective the vest is at protecting against radiation.
The data from all of these sensors won’t be available until the spacecraft returns to Earth. “We look forward to learning what all those sensors will have told us in order to be able to put four human beings on top of Artemis II,” Nelson said.
The two riskiest parts of a space mission are the launch and the landing. With the Artemis hardware having launched successfully, the focus is now on the reentry process. Ahead of splashdown, scheduled for December 11th, the Orion spacecraft will be traveling at 24,500mph. It will dip into the upper atmosphere before pulling up again to reduce its speed. It will then enter the atmosphere for descent, traveling at 17,000mph. Orion will be slowed by parachutes before splashing down into the Pacific Ocean, where it will be recovered by US Navy ships.
Nelson emphasized the importance of this mission as a test ahead of putting human astronauts into the spacecraft. “It is a test,” Nelson said. “And that’s what we do. We stress it, and we test it.”