SpaceX founder Elon Musk announces company plans to send capsule to Mars in 2018

The move will be the first step on the way to colonising Mars - which Musk has previously said is his insurance plan for human life on Earth

SpaceX founder Elon Musk plans to send a capsule to Mars in 2018.

The company is going to send one of its Dragon capsules - in this case known as the Red Dragon - to the planet. It won’t carry any astronauts with it, but represents Mr Musk’s first step towards his ultimate plan of colonising Mars.

For now, the Dragon is too small to carry astronauts further than the Moon, he said, since it is about the size of a large family car. "Wouldn't be fun for longer journeys," Mr Musk explained in a tweet.

But the mission could be proof of the possibility of travelling to Mars, and human missions could follow soon behind. Mr Musk has said that he sees Mars as a kind of insurance plan for life on Earth, and companies like SpaceX are expected to play an important part in future space travel as private firms play more and more of a part.

California-based SpaceX is already using Dragons for space station supply runs, and the company could start flying Americans to the International Space Station by the end of next year.

Mr Musk said the upgraded Dragon is designed to land anywhere in the solar system. Its propulsive landing system was tested recently at the SpaceX plant in McGregor, Texas.

Red Dragon would be launched aboard a mightier version of the current SpaceX Falcon rocket that may make its debut at Florida's Kennedy Space Centre by the end of the year.

Mr Musk has promised additional details on his overall Mars plan. After successfully landing a leftover Falcon booster at sea earlier this month, he said he would elaborate on his approach to establishing a city on Mars at an aerospace meeting in Mexico in September.

He told reporters: "I think it's going to sound pretty crazy. So it should be at least entertaining."

Mr Musk said reusing rockets is key to reducing launch costs and opening up space. SpaceX has now managed to land a first-stage booster on land, as well as on an ocean platform. The recently retrieved booster could fly again on another satellite mission this summer.

Nasa, meanwhile, has its own exploration programme, intended to send astronauts to Mars in the 2030s. The space agency contracted out station deliveries in the post-shuttle era in order to focus on that long-term goal.

Shortly after the SpaceX announcement, Nasa's deputy administrator, Dava Newman, said the space agency will offer technical support to Mr Musk's company in exchange for Red Dragon descent and landing data from Mars. She said no money will be exchanged.

"Sending astronauts to Mars, which will be one of the greatest feats of human innovation in the history of civilisation, carries with it many, many puzzles to piece together," Ms Newman wrote in a blog.

"That's why we at Nasa have made it a priority to reach out to partners in boardrooms, classrooms, laboratories, space agencies and even garages across our country and around the world."

The window to embark on a Mars mission - whether robotic or human - comes up only every two years because of planetary alignment.

Additional reporting by agencies