The NASA Perseverance rover, which arrived brilliantly on Mars Thursday, is the fifth to make the trip a success.
So when is the human turn?
The goal has been stated for decades, but the journey is not yet for tomorrow.
"By the middle to the end of the 2030s, we may start to use the means that we use to get to the moon to send astronauts to Mars," Steve Jurczyk, acting NASA administrator, said Thursday. .
The big technological challenges are more or less solved, yet many factors are still missing from the equation.
- Technical challenges -
A trip to Mars will last about seven months, and astronauts will initially spend 30 days there, NASA anticipates.
It is -63 ° C on average, the radiation is high, and the air is 95% carbon dioxide.
The gravity there is only 38% that of the Earth.
But thanks to "the International Space Station, we have learned a lot about microgravity," said G. Scott Hubbard, a former NASA who led the first Martian program.
But many techniques and materials still need to be tested.
Perseverance took several instruments in order to prepare for future human missions.
Notably MOXIE, the size of a car battery, in an attempt to produce oxygen directly on the spot, by sucking in the CO2 - much like a plant.
The oxygen can be used for breathing, but also as fuel.
And the famous Artemis back to the Moon program, on which NASA is now focusing its efforts, is seen as a test bed towards Mars.
A new suit, xEMU, will be tested there, allowing better mobility and protecting against very low temperatures.
But also a mini nuclear power station to produce electricity, including during dust storms, which can block the Sun for months on Mars (no more solar panels).
The advantage of testing everything first on the Moon?
The possibility of sending help.
On Mars, "if things go wrong and break, you're years from home," Jonathan McDowell of the Harvard-Smithsonian Center for Astrophysics told AFP.
Humans on Mars, "it is doable, but for the moment, it is safer to send robots", for which the required safety standards are lower, summarizes Laura Forczyk, analyst of the space sector.
- Political will -
The big obstacle remains political will - and the funding that goes with it.
In 1990, George HW Bush announced a man on Mars before the fiftieth anniversary of the first step on the moon, in July 2019.
Similar promises from three of his successors (Bush Jr., Barack Obama and Donald Trump) have not given rise to any concrete program.
"It is possible (...) but without the political will of the administration and the Congress, it will not happen", underlines G. Scott Hubbard.
Joe Biden has not yet appointed a permanent administrator for NASA, nor given his space vision for the moment.
His spokesperson confined himself to ensuring "support" the Artémis program.
The goal of an astronaut's return to the Moon for 2024 will suffer "delays", and as a "domino effect", there will be a delay for Mars too, warns Laura Forczyk, deeming the 2040s more credible for the planet red.
- NASA dubbed by SpaceX?
Could NASA thus be overtaken by SpaceX, the company of billionaire Elon Musk, created with the stated goal of allowing the colonization of Mars?
For the trip, the American space agency has bet everything on its SLS (Space Launch System) rocket which must be tested at the end of 2021 at the earliest, without humans on board.
It has already suffered additional costs and delays, including a failed engine test in January.
SpaceX is developing the Starship rocket, two prototypes of which recently crashed into huge fireballs during tests.
Unlike taxpayer funded agencies, Elon Musk invests his own money, so he can take whatever risks he wants.
More than a competition, NASA and SpaceX could therefore become partners, to finally achieve the feat.
© 2021 AFP