NASA is set to launch an ambitious mission to Mars tomorrow with the lift-off of its next-generation Perseverance rover, a six-wheeled robot tasked with deploying a mini helicopter, testing out equipment for future human missions and searching for traces of past Martian life.

The $2.4bn mission, scheduled for lift-off at 12.50 Irish time from Florida's Cape Canaveral, is planned as the US space agency's ninth trek to the Martian surface.

The United Arab Emirates and China separately this month launched probes to Mars in displays of technological prowess and ambition.

Launching atop an Atlas 5 rocket from the Boeing-Lockheed joint venture United Launch Alliance, the car-sized Perseverance rover is expected to reach Mars next February.

A close-up view of a full size model of the Ingenuity helicopter

It is due to land at the base of a 250-meter crater called Jezero, a former lake from 3.5 billion years ago that scientists believe could hold traces of potential past microbial Martian life.

"This is the first time in history where we're going to go to Mars with an explicit mission to find life on another world," NASA administrator Jim Bridenstine told a news briefing.

The rover will attempt for the first time to bring Martian rock samples back to Earth, collecting materials in cigar-sized capsules and leaving them scattered on the surface for retrieval by a future "fetch" rover.

That conceptual rover is expected to launch the samples back into space to link up with other spacecraft for an eventual Earth homecoming around 2031.

Pathfinder lander and Sojourner rover at the Air And Space Museum in Chantilly, Virginia

Also aboard Perseverance is a 1.8-kg autonomous helicopter dubbed Ingenuity that is due to test powered flight on Mars for the first time.

"Imagine a day when we land a robot on Mars and that robot can send maybe a dozen helicopters in different directions to make different discoveries," Mr Bridenstine said.

Since NASA's first Mars rover Sojourner landed in 1997, the agency has sent two others - Spirit and Opportunity - that have revealed the geology of vast Martian plains and found evidence of past water formations, among other discoveries.

NASA has successfully sent three landers - Pathfinder, Phoenix, InSight - as well.

The United States has plans to send astronauts to Mars in the 2030s under its Artemis program, which envisions using a return to the Moon as a testing platform for human missions before making the bigger leap to Mars.