Illustration of NASA’s Orion spacecraft reentering Earth’s ambiance. Credit: NASA
As NASA’s Artemis I mission to the Moon draws to a close, the Orion spacecraft is on its way back to Earth, with the planned splashdown on Sunday, December 11, fast approaching. When Orion is nearing its return to Earth, it will attempt the first skip entry for a human spacecraft. This maneuver is designed to pinpoint its landing spot in the Pacific Ocean.
During this skip entry, Orion will dip into the upper part of Earth’s atmosphere and use that atmosphere, along with the lift of the capsule, to skip back out of the atmosphere, then reenter for final descent under parachutes and splashdown. It’s a little like skipping a rock across the water in a river or lake.
“The skip entry will help Orion land closer to the coast of the United States, where recovery crews will be waiting to bring the spacecraft back to land,” said Chris Madsen, Orion guidance, navigation and control subsystem manager. “When we fly crew in Orion beginning with Artemis II, landing accuracy will really help make sure we can retrieve the crew quickly and reduces the number of resources we will need to have stationed in the Pacific Ocean to assist in recovery.”
Ever skip stones throughout a pond? Imagine doing it with a spacecraft. When the Lockheed Martin-built Orion spacecraft returns to Earth on the finish of the Artemis I mission, it’ll try a never-been-done steerage and management maneuver known as a skip-entry. This maneuver permits for a exact touchdown location for safer crew restoration efforts.
During Apollo, the spacecraft entered the Earth’s ambiance immediately and will then journey as much as 1,725 miles (1,500 nautical miles / 2,880 km) past that location earlier than splashing down. This restricted vary required U.S. Navy ships to be stationed in a number of, distant ocean areas. By utilizing a skip entry, Orion can fly as much as 5,524 miles (4,800 nautical miles / 8,890 km) past the purpose of entry, permitting the spacecraft to the touch down with extra precision. The skip entry finally permits the spacecraft to precisely and constantly land on the identical touchdown web site no matter when and the place it comes again from the Moon.
“We extend the range by skipping back up out of the atmosphere where there is little to no drag on the capsule. With little or no drag, we extend the range we fly,” mentioned Madsen. “We use our capsule lift to target how high we skip, and thus how far we skip.”
Although the idea of the skip entry has been round for the reason that Apollo period, it wasn’t used as a result of Apollo lacked the mandatory navigational know-how, computing energy, and accuracy.
“We took a lot of that Apollo knowledge and put it into the Orion design with the goal of making a more reliable and safer vehicle at lower cost,” mentioned Madsen. “These are some of the things we’re doing that are different and provide more capability than Apollo.”
This graph exhibits the extent to which the Orion spacecraft’s vary will be prolonged with a skip entry, in comparison with the vary the Apollo spacecraft was in a position to fly with a direct entry. Credit: NASA
The skip entry additionally will enable astronauts to expertise decrease g-forces throughout Earth entry from Moon missions. Instead of a single occasion of excessive acceleration, there will probably be two occasions of a decrease acceleration of about 4 g’s every. The skip entry will scale back the acceleration load for the astronauts in order that they have a safer, smoother trip.
Splitting up the acceleration occasions additionally splits up the heating, no small matter for a spacecraft that can endure roughly 5,000 levels Fahrenheit (2,800 degrees Celsius) upon reentry, half as hot as the surface of the Sun. The heat the spacecraft will experience upon reentry will be split over two events causing a lower heat rate at both occurrences and ultimately making it a safer ride for the astronauts.
During Artemis missions, Orion will splashdown approximately 50 miles (43 nautical miles / 80 km) off the coast of San Diego, California, where rescue teams are close and can quickly recover the spacecraft. This quick recovery will make it safer for the astronauts. It will also be more cost-efficient than Apollo by eliminating the need for the Navy to deploy ships widely across the target ocean.
As an essential part of NASA’s Artemis program, the Orion spacecraft will fly on NASA’s first integrated test of its deep space exploration systems during Artemis I. The Space Launch System rocket will launch an uncrewed Orion on a mission to travel 40,000 miles beyond the Moon and then return to Earth.
