The Orion spacecraft is set to make its closest approach to the moon today, passing behind the orb for a little more than 30 minutes before skimming 80 or so miles above its surface. The flyby will take place at 7:44 am EST, and can be viewed over the NASA Artemis I stream.
Flight controllers at NASA’s Johnson Space Center in Houston had a busy weekend maneuvering Orion between Earth and its satellite. The team performed three trajectory correction burns with thrusters to nudge the capsule into the perfect spot and speed for one of the Artemis I mission’s mileposts. As a result, the vehicle moved into “the lunar sphere of influence,” or more simply put, the moon’s gravitational field.
But the work doesn’t end there. The flyby will require precision in both navigation and propulsion to get maximum assistance from the moon’s gravity (which is only about a sixth as powerful as Earth’s). To enter the optimal elliptical pathway, Orion will use its main engine to push away from its destination and essentially, slingshot around it. The spacecraft is currently traveling at 547 miles per hour, though its velocity will change dramatically as lunar forces take over.
[Related: Have we been measuring gravity wrong this whole time?]
At 80 miles from the moon, Orion will snap images of the bumpy surface with its 16 onboard cameras. Other missions have made closer contact: The US, former Soviet Union, and China combined have 21 successful lunar landings since the 1960s. But it’s important to remember that Artemis I is forging a path, somewhat literally, to exploring new regions of the moon. It will help NASA scientists finetune their measurements and procedures for sending more space systems, and one day, astronauts, to the satellite’s south pole.
Orion’s route over the next 19 days involves maximum coasting. One of the current mission’s objectives is to see how well the capsule will fare in distant retrograde orbit, or DRO. This high-altitude, clockwise movement will bring the spacecraft around the moon 1.5 times—with minimum fuel use. Orion is already loaded with four first-of-its-kind solar arrays, which have been producing enough electricity to run two average US homes. DRO, however, will let it cut down power use, except for with instruments and further trajectory burns.
On the opposite end of its travels, the capsule will edge 40,000 miles past the far side of the moon, which is the farthest any habitable vehicle has gone in space. At that point of the orbit, it will be close to 300,000 miles away from Earth. Orion should hit that point in early December, and then start making its circuitous way back home.
Watch the most up-to-date action here: