Starting this week, humanity is sending a wave of unmanned spacecraft to Mars to see if it was ever habitable and find out if it could be again.
The three spacecraft, which are being sent by the United States, China and the United Arab Emirates, will land on or orbit the red planet next year after at least a six-month journey.
The timing of the launches has been dictated by Mars and Earth’s orbits, with a single one-month window opening in July during which the planets are close enough together on the same side of the sun to permit the six-month journey.
If the launches fail or are postponed, this window won’t open again for another 26 months.
NASA is sending its six-wheeled Perseverance rover, which is about the size of a car, to drill into the planet and collect rock samples.
The robotic vehicle will explore Mars and test a method for producing oxygen from the Martian atmosphere, which could potentially be used by astronauts living and working on the planet in the future.
Each of the spacecraft being launched this month will need to travel more than 300 million miles (483 million kilometres) before reaching Mars next February.
They aim to examine what the red planet was like billions of years ago when it is believed to have had rivers, lakes and oceans that may have allowed simple, tiny organisms to flourish.
“Trying to confirm that life existed on another planet, it’s a tall order. It has a very high burden of proof,” said Ken Farley, Perseverance’s project scientist based at Caltech in Pasadena, California.
Missions to Mars are rarely successful, and only the US has actually managed to put a spacecraft on the planet’s surface – which it has done eight times.
More than half of the spacecraft sent there have either blown up, burned up or crashed into the surface, including China’s last attempt – in collaboration with Russia – in 2011.
China’s space agency hasn’t released many details about its launch or mission, although it is called Tianwen, which means Questions for Heaven.
The first spacecraft to launch during this window will be the UAE’s, named Amal – meaning Hope in Arabic – which is scheduled to launch from Japan this Wednesday.
“The UAE wanted to send a very strong message to the Arab youth,” project manager Omran Sharaf said. “The message here is that if the UAE can reach Mars in less than 50 years, then you can do much more.”
Amal will be controlled from Dubai and will study the Martian atmosphere and climate from a high-orbit altitude.
China’s Tianwen lander is then expected to launch on 23 July.
NASA’s launch is currently scheduled for 30 July and the Perseverance rover is intended to touch down in an ancient river delta and former lake on the Martian surface known as the Jezero Crater.
Both NASA and China’s spacecraft will need to plummet through the Martian atmosphere before landing, something which NASA’s teams have dubbed the “seven minutes of terror” considering the high rate of failure to land on the planet.
Jezero Crater is full of obstacles and dangers to the rover, including boulders, cliffs, sand dunes and depressions, any one of which could end the mission.
NASA hopes its brand-new guidance and parachute-triggering technology will help steer the rover away from these hazards but its controllers back on Earth will be helpless.
Radio transmissions from Mars take 10 minutes to reach Earth so by the time the controllers see Perseverance has entered the atmosphere, it will have either already landed or been destroyed.
The remnants of microbial life on Mars could have left telltale marks in the sediment layers which Perseverance will drill down into.
After drilling into the best rocks the rover will cache about half a kilogram of rock sample in dozens of titanium tubes that will be collected by another rover in approximately a decade’s time.
Both Perseverance and the Chinese rover will also use radar to scan beneath the surface of the planet, searching for any underground pools of water that might exist there.
Perseverance is also equipped with a miniature helicopter which weighs just 4lb (1.8kg) and will be the first rotorcraft to fly on another planet.
NASA intends to send the first woman to the moon in 2024 and from there the first astronauts to Mars in the 2030s, and so some samples of its spacesuit material are also being sent with Perseverance to analyse how they stand up against the Martian environment.