Project Artemis

The Artemis program is a robotic and human Moon exploration program led by the United States’ National Aeronautics and Space Administration (NASA) along with three partners: European Space Agency, Japan Aerospace Exploration Agency, and Canadian Space Agency.

Artemis 1 successfully completed its mission back in November of 2022. The orbital trajectory is shown in the top graphic. It was the first full scale test of NASA’s new Space Launch System (SLS) and carried an unmanned Orion crew capsule. It flew to the Moon, looped around the Moon twice, then fired its engines to break away from the Moon’s gravity and return to Earth. Just before reentry, the crew module separated from the ICPS, rotated to orient its heat shield, and reentered the atmosphere. It splashed down in the Pacific off the coast of Baja California.

The Artemis II mission is currently scheduled for November 2024. It will carry a crew of four astronauts, three American and one Canadian.This will be a simpler flight path than Artemis I, as you can see in the graphic below:

Artemis II will mark the first return of humans to the Moon since Apollo 17 in 1972. As with Apollo 8 back in December 1968, Artemis II will not land on the Moon. Instead, it will loop around the Moon using the Moon’s gravity to slingshot back to Earth — a maneuver called free return trajectory. At closest approach to the Moon they will be at an altitude of 7,400 km (4,600 miles).

Artemis III will be the most complex mission. The mission goals include a manned landing near the lunar south pole, where two astronauts will spend around a week on the surface conducting various experiments. One of the most important investigations centers around the search for water ice, an important resource suspected to exist in permanently shadowed craters near the Moon’s poles.

Establishing a permanent colony on the Moon will be much easier if the water ice is there. Water is prohibitively heavy to ship in large quantities from Earth, so we hope to be able to “mine” it on the Moon. Water can be used for drinking, of course, but it can also be used to make breathable oxygen and rocket fuel via the process of electrolysis.

Landing on the Moon’s south pole requires a complex maneuver that puts the ship into what is called a halo orbit. All the Apollo landings used simple equatorial trajectories which are the easiest to execute. They resembled the trajectory planned for Artemis II. The graphic below shows the landing sites for the Apollo missions. All were on the familiar Earth-facing side of the Moon and relatively near its equator:

The halo orbit, by comparison, is a polar orbit around the Moon. This is required for a polar landing. As seen from Earth, the orbit would look like an ellipse with the Moon at one focus. This is a gravitationally stable configuration even though the Moon is in motion around the Earth. It’s the same orbit planned for NASA’s lunar Gateway. which will be deployed and assembled by Artemis IV and V.

This what the mission trajectory looks like for Artemis III:

Artemis III will actually be a joint mission involving NASA and SpaceX. Prior to the SLS Orion launch, SpaceX will launch an unmanned Starship HLS (Human Landing System), guide it to the Moon, and place it in the same halo orbit shown in the above graphic. There it will await rendezvous with Orion. SpaceX is currently preparing to send an unmanned HLS to the Moon to demonstrate a safe landing and return to orbit.

After Orion docks with the HLS two astronauts will transfer into it and prepare for their descent to the lunar surface. The other two astronauts will remain on Orion. The HLS will be carrying enough food and water for the astronauts’ stay on the surface, as well as some scientific instrumentation.

Potential landing sites are shown in the graphic below. It’s a fairly rugged region that requires careful maneuvering to avoid landing on a sloped surface. HLS is designed for VTOL and must land on a horizontal surface. SpaceX has demonstrated its VTOL capabilities on multiple occasions. You can watch the first successful SpaceX VTOL flight in the video here.

Artemis III is currently scheduled for launch in December of 2025, but with the HLS still in development (SpaceX just blew up a Starship on April 20) there may be some delays. Still, it is exciting to know that we are finally returning to the Moon.

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