On Flight Day 16, a camera mounted on one of Orion’s solar arrays captured this image of our Moon as the spacecraft prepared to depart from distant retrograde orbit during the Artemis I mission. Credit: NASA
On the 16th day of the Artemis I flight, Orion left its distant lunar orbit and began its journey back home. The spacecraft successfully completed the distant retrograde exit burn at 3:53 pm CST, firing its main engine to set the spacecraft on course for a close lunar flyby before returning home.
The 1 minute 45 second burn changed Orion’s speed by about 454 feet per second. It was carried out using the Orion main engine in the European Service Module. The engine is an Orbital Maneuvering System engine modified for use on Orion and built by Aerojet Rocketdyne. The engine is capable of providing 6,000 pounds of thrust. The tested engine flying on Artemis I made 19 space shuttle flights, beginning with STS-41G (the 13th flight of the space shuttle program) in October 1984 and ending with STS-112 (the space shuttle mission 111) in October 2002.
The burn is one of two maneuvers required before Orion splashes into the Pacific Ocean on December 11. The second will occur on Monday, December 5, when the spacecraft will fly 79.2 miles (127 km) above the lunar surface and make a powered return. flyby burn, which will compromise Orion on its course towards Earth.
The teams also continued thermal testing of the star trackers during their eighth and final planned test. Star trackers are a navigational tool that measure the position of the stars to help the spacecraft determine its orientation. During the first three days of the mission’s flight, engineers evaluated initial data to understand the star tracker readings correlated with thruster firing.
A trajectory correction burn occurred at approximately 9:53 pm CST on Thursday, December 1, with Orion’s auxiliary thrusters adjusting the spacecraft’s path.
Shortly after 4:30 pm CST on December 1, Orion was traveling 237,600 miles (382,400 km) from Earth and 52,900 miles (85,100 km) from the Moon, cruising at 2,300 mph (3,700 km/h).