NASA will deploy the Ingenuity Mars "helicopter" on the rover Perseverance. The state of the art helicopter weighs 1.8 kilogram which will attempt to fly in an atmosphere that is only one per cent density of the Earth.
The experimental mini-helicopter will be the first chopper to take flight on another planet, if all goes to plan the take-off is scheduled for 1150 GMT from Cape Canaveral, Florida today on board a United Launch Alliance Atlas V rocket.
Perseverance is set to reach Mars on February 18, next year becoming the fifth rover to complete the voyage since 1997.
The Perseverance rover will seek signs of ancient life and collect rock and soil samples for possible return to Earth. More than 350 geologists, geochemists, astrobiologists, atmospheric specialists and other scientists from around the world are taking part in the mission.
It is set to last at least two years, but probably much longer given the endurance shown by previous rovers.
US, China war in Mars
With Thursday's launch, the United States will become the third nation to embark on a mission to the Red Planet this month. China launched a rover to Mars last week named Tianwen-1 ("Questions to Heaven").
If China's mission succeeds, it will become only the second nation after the United States to have a rover on another planet -- though it has previously placed two rovers on the Moon.
United Arab Emirates launched Hope
The United Arab Emirates also launched an orbital probe from Japan earlier this month called "Al-Amal" (Hope), the Arab world's first mission to Mars. China's Mars probe lifted off on July 23 from the southern island of Hainan.
China's Questions to Heaven
China's mission was dubbed Tianwen-1 ("Questions to Heaven") in a nod to a classical Chinese poem that has verses about the cosmos. China sent two rovers to the Moon, Jade Rabbit One and Two (Yutu in Chinese), in 2013 and 2019.
The second rover made a historic soft landing on the far side of the Moon, making China the first country to do so.
China's rover weighing 240 kilogrammes (530 pounds), has six wheels and four solar panels, Chinese state media reported.
The rover will roam Mars for three months, according to Sun Zezhou, chief engineer of the probe. The machine is supposed to analyse the planet's soil and atmosphere, take photos, chart maps and look for signs of past life.
Ingenuity helicopter to Mars
Perseverance's primary mission is to scour the planet for evidence of ancient life forms.
Scientists believe that more than three billion years ago the planet was much warmer than today and was covered in rivers and lakes, conditions which could have led to simple microbial life.
The reasons for it becoming the cold, barren world we know today aren't fully known.
Another first: Perseverance's drill will collect around 30 intact rock cores and place them in test tubes, to be collected by a future joint US-European mission.