The billionaire businessman hopes to use his SpaceX company to establish a self-sustaining base for humanity on Mars to ensure the long-term survival of the human race before the Earth is eventually destroyed by the Sun - and he's now declared he sees the scheme as necessary even though it's proving to be "very difficult".

During an interview with Fox News' Jesse Watters, Musk explained: "Going to Mars to build a self-sustaining civilisation on Mars, that is a very difficult thing which SpaceX has not yet done. And we've yet to send anything to Mars."

He added: "It’s not about going to Mars to visit once, but it is to make life multi-planetary so that we can expand the scope and scale of consciousness to better understand the nature of the universe and to ensure the long-term survival of civilisation in the hopefully unlikely event that something terrible happens to Earth that there is a continuance of consciousness on Mars ...

"That’s one of the benefits from Mars, it’s life insurance collectively. Eventually, all life on earth will be destroyed by the Sun. The Sun is gradually expanding, and so we do at some point need to be a multi-planet civilisation because Earth will be incinerated."

However, he added we have "several million years" before the worst happens.

He went on to say: "If Earth has been around for around four and half billion years, which is what the fossil record suggests then Earth inly has about 10 per cent more life in it before it gets so hot that life isn't possible ...

"We're headed there [Mars], we have a long way to go because it's not just about landing on Mars and doing flags and footprints it about creating a self-sustaining city on Mars with the fundamental fork in the road of destiny being that Mars is sufficiently self-sustaining and can grow by itself.

"If the resupply ships from Earth stop coming for any reason whether that is because civilisation died with a bang or a whimper. But if the resupply ships are necessary for Mars to survive then we have not created life insurance ... "

"That's the key point in the future where desiny of life as we know if will forever be affected is when Mars becomes self-sustaining."