After visiting the Moon and venturing further into space than any habitable spacecraft before it, NASA’s Orion capsule is due to splash down in the Pacific Ocean on Sunday, the final leg of the high-stakes Artemis 1 mission. for the US space agency.
The capsule will enter the Earth’s atmosphere at a speed of 40,000 km/h, and will have to withstand an infernal heat of 2,800°C, which is half the temperature of the surface of the Sun.
The landing is scheduled off the Mexican island of Guadalupe at 5:39 p.m. GMT (9:39 a.m. local time).
The success of this mission, which will have lasted just over 25 days in total, is crucial for NASA, which has invested tens of billions of dollars in the American program to return to the Moon, Artemis, whose goal is to prepare for a future trip to Mars.
The first test flight of this brand new vehicle – without an astronaut on board this time – has so far been a real success.
But it is only during the last minutes of the mission that its main objective must be accomplished: testing the capsule’s heat shield, the largest ever built (5 m in diameter).
“It’s a critical piece of safety, designed to protect the spacecraft and its passengers,” explained Mike Sarafin, mission manager. “The heat shield has to work. »
In 2014, a first test of the capsule had been carried out, but it had not then left Earth orbit, and had therefore entered the atmosphere more slowly (around 32,000 km/h).
Helicopters, divers and boats
A US Navy ship, the USS Portland, has been prepositioned for capsule recovery operations, which NASA has been training for years. Helicopters and inflatable boats will also be deployed.
The spacecraft will first be slowed down by the Earth’s atmosphere, then by a series of no less than eleven parachutes, until it reaches a speed of around 30 km/h when it hits the water.
Once landed, it will be left in the water for two hours, much longer than if astronauts were on board, in order to collect data.
“We will see how the heat is absorbed by the capsule and how this affects the temperature inside”, detailed Jim Geffre, responsible for Orion at NASA.
Then divers will attach cables to it in order to tow it to the interior of the ship, the rear of which will be partly submerged. The water will then be pumped, allowing the capsule to be slowly deposited on a support provided for this purpose.
Operations are expected to take four to six hours from the time of landing.
The ship will then take the road to San Diego, on the American west coast, where the capsule will be disembarked a few days later.
In total, the spacecraft will have traveled more than 2.2 million kilometers in space since its takeoff on November 16 during the first flight of NASA’s new mega-rocket, SLS.
Orion flew by the Moon only some 130 kilometers from its surface, and ventured up to more than 430,000 km from our planet.
Artemis 2 and 3
Recovering the capsule will allow the collection of a lot of decisive data for the following missions. First by detailing the state of the ship after its trip, but also by analyzing the recordings of sensors of the accelerations and vibrations undergone on board, or the performance of an anti-radiation jacket.
Some elements of the ship must also be reused for the Artemis 2 capsule, which is already well advanced.
This second mission, scheduled for 2024, will take a crew to the Moon, still without landing there. NASA should announce the names of the chosen astronauts very soon.
Artemis 3, officially scheduled for 2025, will land for the first time on the South Pole of the Moon, where there is water in the form of ice.
Only twelve men, all white, have set foot on the lunar surface thanks to the Apollo missions – for the last time in 1972, fifty years ago.
The Artemis program must this time send the first woman and the first person of color there.
NASA’s goal is to establish a lasting human presence on the Moon, with a base on its surface and a space station orbiting it. Learning to live on the Moon should test all the technologies needed for a multi-year journey to Mars — possibly in the late 2030s.