NASA’s Orion spacecraft has re-entered the area of the moon’s gravity, called the lunar sphere of influence, on its way back to Earth. The spacecraft is currently traveling on the Artemis I mission around the moon, and this milestone marks a significant point on its return journey as the moon becomes the primary gravitational force acting on the spacecraft.
Orion entered the lunar sphere of influence at 5:45 p.m. ET on Saturday, December 3, when the spacecraft was located just under 40,000 miles from the moon’s surface. It will now continue to travel in this sphere of influence until Tuesday, December 6, when it will exit and head back toward Earth.
Orion also recently tested out its reaction control thrusters, which are the engines that will be used during the craft’s re-entry into Earth’s atmosphere. “While the crew module thrusters will be tested a few days before Orion’s splashdown on Earth, their primary role takes place in the final hour before splashdown in the Pacific Ocean,” NASA writes in an update. “After the crew module and service module separate the crew module’s RCS thrusters will be used to ensure the spacecraft is properly oriented for re-entry, with its heat shield pointed forward, and stable during descent under parachutes.”
This test, like the Artemis I mission more broadly, is part of the preparations for the planned Artemis II mission which will be crewed. A group of astronauts will enter Orion and travel on a similar trajectory to the Artemis I mission, traveling around the moon. Then, a future Artemis III mission aims to land astronauts on the moon’s surface. Before a crewed mission can happen, though, the new hardware such as the Space Launch System rocket and Orion spacecraft needed to be tested, which is the purpose of this current uncrewed mission.