December 19, 1972, a little after 7 p.m., in the south-west of the Samoa archipelago. In a big splash, the Apollo 17 capsule, with Harrison Schmitt, Gene Cernan and Ronald Evans on board, lands successfully on the Pacific Ocean, marking the end of a historic adventure. Nearly half a century later, Chinese advances in space and the presidency of Donald Trump have reignited the race for the Moon. The first stage is due to take place on August 29.
In 2019, China becomes the first nation to reach the far side of our natural satellite with the Chang’e-4 mission. Immediate reaction, Donald Trump increases NASA’s budget and announces that “We’ll be back on the moon shortly, and one day soon we’ll be planting the American flag on Mars”. The American program is called Artemis, named after Apollo’s twin Greek goddess. A way also for NASA to signal that the next human to set foot on the lunar star will be a woman.
Up to 46 tons of material transported
Before sending astronauts, starting in 2025 with the third Artemis mission, this summer’s takeoff serves as a full-scale rehearsal. In fifty years, technologies have evolved, engineers have changed and everything has been redesigned to redo the 384,000 kilometer journey. Starting with the rocket. “Reaching lunar orbit requires significantly more power than going to low orbit, it’s 1,000 times further than where the International Space Station is located.explains Christophe Bonnal, expert in the launcher department of the National Center for Space Studies. So if you also want to take astronauts and equipment there…»
The titan designed for this showdown is called SLS, for Space Launch System. In its first version, the rocket will be able to take 27 tons to the Moon, a capacity that will increase to 46 tons later. This machine embodies “the result of the hard work of thousands of people around the world”, welcomed Bill Nelson, the administrator of NASA.
For its premiere, SLS will be driven by four main engines from the former US space shuttle. Since the end of the program in 2011, sixteen of these machines have been sleeping in hangars. Engineers have brought them up to date for the needs of the rocket, the most powerful currently. For the rest, NASA subcontractors have started a new production of engines. “Just because we knew how to go to the Moon in the 1970s doesn’t mean we know how to do it again easily todaytestifies Christophe Bonnal. They are no longer the same materials, no longer the same safety standards and a large part of the industrial fabric has disappeared.»
The Orion ship built in Europe
“The SLS is a legacy of the space shuttle in its design, but with many new features and therefore a share of risks to be tested”, supports Philippe Deloo, responsible for the European Space Agency, ESA. On takeoff, the effects of the ignition of the boosters, the “boosters” on each side, will for example be closely scrutinized, with the risk of vibrations for the main body of the rocket. In total, a hundred points must be checked during this first mission, thanks to thousands of onboard sensors.
If the SLS rocket represents the big technical and financial piece of the Artemis program, NASA will also examine the Orion spacecraft, which must take the astronauts. “We will particularly look at the brand new heat shield”, says Howard Hu, responsible for NASA. When the crew returns to Earth, this shield must protect against heat from friction, while the Orion spacecraft goes from a speed of 40,000 km / h to almost 0. “We spent hundreds of thousands of hours testing the elements on Earth, now we have to see the whole thing in real conditions”continues the manager.
Americans won’t be the only ones holding their breath. The Orion ship was built in partnership with the Europeans. “We provide the service modules, which ensure the propulsion of the ship, the electricity supply thanks to solar panels, and the water and oxygen supply.describes Philippe Deloo, who manages this part of the program on the European side. The first module, for the Artemis 1 flight, was delivered in 2018 to NASA.» The second is also across the Atlantic, in the hangars of the American Space Agency. A third is under construction in Bremen, Germany.
A space station orbiting the Moon?
“The element is critical for the success of missions to the Moon, it is an important mark of confidence on the part of NASA”, welcomes Didier Schmitt, in charge of robotic and human exploration at ESA. In exchange, Europe is guaranteed at least three seats for its astronauts, a priori from the Artemis 4 mission. “We are in discussions with NASA so that a European astronaut can walk on the Moon before the end of the decade and not only go there in orbit»we confide to the ESA.
Proof if need be that the Moon represents a symbolic objective, in addition to a scientific mission. If there is still a lot to learn about lunar geology and the beginnings of the solar system, the Artemis program will above all serve as a springboard for what follows. “We are returning to the Moon to learn how to survive harsh conditions and use available resources to go further afterwards”confirms Bill Nelson. “Our eyes are on Mars”adds Reid Wiseman, head of the astronaut department at NASA.
Before arriving in sight of the red planet, the American project provides for the construction of a space station, like the existing one, but in orbit around the Moon and not the Earth. The “Gateway” will be assembled element by element in space and will then serve as an outpost for ever further journeys. Goals worthy of science fiction. But after all, it took less than twenty years for humanity to achieve what Hergé drew in 1953 in Objective moon…
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A financial and climatic cost
In November 2021, a NASA report put forward a total cost of 93 billion dollars for this program by 2025. European participation amounts to 2.1 billion euros. A considerable sum, but less than the Apollo program, which had cost the equivalent of 170 billion current dollars.
The environmental cost of space can no longer be ignored, with the development of tourism and more than 130 launches last year. If NASA does not communicate on the impact of Artemis 1, researchers have calculated that a takeoff of a SpaceX Falcon 9 rocket emitted 116 tons of CO2 in just 165 seconds.