The Orion capsule housing the four astronauts of the Artemis 2 mission will land off the coast of San Diego this Friday, April 10 at 5 p.m. local time.
The astronauts of the Artemis 2 mission are preparing to enter the most difficult stage of their journey. After nine days of mission, Christina Koch, Victor Glover, Reid Wiseman and the Canadian Jeremy Hansen will set foot on land for the first time after having moved more than 400,000 kilometers of the Earth. They therefore beat the old Apollo 13 record of 6,000 km dating from 1970. As a reminder, the goal of the mission was to observe the hidden side of the Moon. This hidden face had until now only been observed by telescopes. For Philippe Lognonné, interviewed by the daily The Worldthe Artemis 2 mission also constitutes “essential preparation for future Moon landing missions, starting with Artemis 4”.
A return with fanfare for the Artemis 2 mission
For its return, the Artemis 2 mission capsule is preparing to reach astonishing speed. When it returned in 2022, the Artemis 1 mission capsule reached a speed of Mach 32, or 38,000 km/h. The four astronauts will therefore be well beyond supersonic speed (Mach 1), which is equivalent to 1,224 km/h.
This impressive descent will limit certain functions of the capsule. For example, all telecommunications will be cut off a few minutes before landing. Burning plasma will also be generated due to air friction. The temperatures will then easily approach the 2,800°Cwhich is equivalent to about half the surface temperature of the Sun. A heat shield with a width of almost five meters will still be present to protect the capsule. This shield, made of resin, is the most imposing element of the ship. His goal? Absorb heat and evacuate it by gradually evaporating. However, some doubts persist regarding this heat shield. They are fueled by the fact that this is the first manned flight of the Orion capsule. However, a problem was detected during a test in 2022.
Solutions provided by NASA
The American space agency had decided to continue with the same shield, without changing its structure or composition. This defect is the cause of the delay in this mission, initially planned for 2024. NASA then investigated for several months in order to understand the phenomenon. They ended up believing that this phenomenon did not call into question the smooth running of the mission.
However, the American space agency made a strong choice: modify the angle of entry into the atmosphere of the Orion capsule. If the angle is too weak, the capsule could ricochet off the atmosphere. If he is too strong, stresses due to air friction could threaten its integrity. NASA has planned a rather special technique to prepare the return to Earth of the four astronauts. This return will be made by ” bounce “a first for a manned vessel. This technique consists of entering the capsule into the upper atmosphere, then bouncing it towards space before diving back to complete its descent. It makes it possible to locate the landing point more precisely and reduce thermal constraints.
Once entering the atmosphere, the crew will have done the most difficult part. Eleven parachutes will deploy and allow landing. The crew will then winched to a ship of the Navy. There, the astronauts will be medically examined before returning to dry land. After landing, NASA will look to the future, as it prepares to reconquer the Moon. This reconquest will first involve the Artemis 3 mission, planned for 2027. It will be used to verify the technical capabilities of the vessel. Finally, the Artémis 4 mission will aim to achieve the first moon landing by a crew since 1972, in 2028.
