How will the Artemis I mission around the Moon unfold?

Article originally published in March 2022.

March 2022 was the first time the launcher SLS (Space Launch System) showed itself completely to the Cape Canaveral public. Accompanied by the Full moon, the SLS dominates the historic launch site as it slowly makes its way to launch pad 39B. It reminds observers and a whole generation of the path taken by the Saturn V towards this same launch pad before sending astronauts on the Moon. It is a key step for the Nasa who has succeded taxiing of the SLS lunar rocket. And now what’s next?

The SLS has arrived on its launch pad, now what?

We will now have to check that the SLS adapts well to its launch pad. NASA has scheduled a dress rehearsal in early April. The exact date is not yet communicated. In this general rehearsal, the test of filling the SLS tanks is notably included. To take off, the rocket Lunar will consumeoxygen and of thehydrogen in the state liquid. If the tanks have already been pre-tested until the explosion, then this is to check that everything works well under the conditions of the launch countdown.

Once the dress rehearsal has passed, NASA will communicate the take-off date. A possible take-off either from May 7 if all goes well, or later in the summer as expected. There will be no one aboard the Orion spacecraft that has been landed atop this titanic launcher. Artemis I is a qualification mission, both for the spacecraft manufactured in Europe and the United States, and especially for the SLS produced by Boeing. If the mission is successful, the astronauts of Artemis II will take over.

” We are ready ! »

Launch pad 39B at the Kennedy Space Center experienced Apollo 10the american space shuttlethe launch of the space station skylabor even the mission of peace Apollo-Soyuz. It has been renovated and reinforced to be able to support a weight equivalent to 2,125 African elephants! It is robust enough to accommodate the 2,628 tons of the SLS lunar rocket. The latter will only play a role in the mission for one hour and fifty-three minutes. The rest of the mission concerns the Orion ship and will last nearly 25 days.

At T-0, the launch will begin with the update fire four RS-25 motors as well as two gigantic thrusters solid fuel boosters supplied by Northrop Grumman. They will be ejected two minutes later, completely emptied of their fuel. The RS-25 engines will continue to roar for another six minutes and fourteen seconds. At this point, the main stage of the SLS, recognizable by its color red, will have finished its work and we will already be at an altitude of more than 150 kilometers, therefore in space.

Two minutes after the main stage was released, the Orion ship will deploy its solar panels. It will have already been rid of its protective panels as well as the rescue tower, an essential device for ejecting the ship and its occupants, if ever the rocket catches fire on the launch pad or while crossing theatmosphere.

It was not until much later, 54 minutes after the start of the launch, that the propulsion of the second stage, the ICPS, supplied by the United launch Alliance (ULA). The ICPS is used a first time to gain altitude and a second time half an hour later to inject the Orion spacecraft on a transfer orbit towards the Moon. Once its mission is complete, the ICPS is dropped. We will then take the opportunity to eject a dozen cubesats who are secondary passengers on this flight.

Around the Moon

This is not the Orion’s first demonstration flight. It has already made a first flight in 2014, as part of the program Constellation, precursor of the Artemis program. This flight will allow him to test once again the manned module, manufactured by Lockheed Martin, as well as the service module provided by the European Space Agency (ESA). The trajectory that Orion will achieve during the Artemis I mission is equivalent to that of the mission Apollo 8.

It will take a little over three days to reach the Moon. To fit into orbit, Orion will pass nearly 100 kilometers from the surface and will use the gravity lunar to increase its speed. With the help of a few corrections, the ship will then go into retrograde orbit around the Moon. Indeed, the spacecraft will revolve around the Moon in the opposite direction to its revolution around the Earth.

The Orion spacecraft will remain a little over six days in orbit around the Moon. NASA will take the opportunity to recover data, test the various communication and navigation systems of the ship. To communicate with him, NASA will use the Deep Space Networkantenna array used to interact with interplanetary probes.

The Orion ship will house an experiment (Mare) whose purpose is to measure the level of radiation to which the occupants of the ship could be exposed. Around the Moon, we are almost no longer protected by the earth’s magnetic field which deflects the particles ejected by the Sun. On board the ship, two mannequins will be covered with sensors and one of them will be wearing an experimental vest that’s supposed to block out some of the radiation.

Return to Earth and continuation of the program

To leave lunar orbit and return to Earth, Orion will once again pass nearly 100 kilometers in altitude to accelerate, not only using lunar gravity to do so but also using the main engine of the service module. It will then place itself in a transfer orbit in the direction of our Planet. The trip should last a little over three days.

It is after a three-week journey covering more than 1.3 million kilometers that the Orion spacecraft will return to Earth. Before entering the Earth’s atmosphere, the habitable module will separate from the service module. The latter is not protected, it will burn in the atmosphere during its fall while the habitable module will pass through it, protected by its heat shield. It will end its descent under parachute. It is supposed to land in the Pacific Ocean off California. The Artemis I mission will then be complete.

We will have to be patient for the rest, depending on the results of this first mission. Artemis II should not take place before 2023, or even 2024. It will be the first mission of the program with astronauts on board but they will not land on the Moon. They will just go around it in “dress rehearsal” mode, as was the case with Apollo 10. This is the mission Artemis III which will bring astronauts back to the surface of our natural satellite, including the first lunar walk in history.