NASA scientists are counting down the days, hours, and minutes before a risky Mars landing that could result in new data about the core of the red planet - or mean a quick and fiery end to a multi-year, billion-dollar project.  

"We've been cruising to Mars for about seven months. What we've been doing on the way there is we've been doing trajectory correction manoeuvres. Those are designed to get us targeted to exactly the right spot in the atmosphere that we need to be in order for us to land where we want to land on Mars," said project manager Tom Hoffman.  

But the landing set for Monday will all come down to a hair-raising six-and-a-half-minute descent from outer space to the rocky surface, a landing will depend on a specially-designed heat shield meant to protect the robot's sensitive instruments from incinerating.

The next phase of the landing sequence includes a supersonic parachute, to further slow the landing.

The robot will detach from the spacecraft, but is still moving too fast for a safe landing.

So on-board thrusters will fire to help ensure a soft touchdown.

If it safely reaches the surface, the robot will then deploy its true payload: two tools aimed to go where none have gone before, beneath the surface of Mars. 

One will create deep vibrations which could tell scientists about the structure of the planet.

The second tool will hammer a spike up to five metres deep to measure the change in temperature.

Both tools will transmit data back to earth that will offer scientists clues as to how Mars was formed, and how it differs from our own planet.

If all systems work, the mission, named Insight, is expected to last two earth years.