The SpaceX bid to land a spacecraft on Mars as soon as 2018 is an extraordinarily ambitious plan under an very tight timeline, even with Nasa's help.
SpaceX made the announcement on Twitter, saying the landing would "inform its overall Mars architecture."
Elon Musk has said his company hopes later this year to unveil its plan to get humans to the Red Planet by as soon as 2025.
Musk, the billionaire entrepreneur who also runs the electric car maker Tesla, founded SpaceX more than 10 years ago with the goal of colonising Mars.
Nasa said it is providing technical support for SpaceX's mission. In exchange, SpaceX would provide "valuable entry, descent and landing data to Nasa for our journey to Mars, while providing support to American industry".
Getting there, however, is exceedingly difficult - even for governments, let alone a privately held space company.
On average, Mars is 225 million km from Earth, though the planets come to within about 56 million km every 26 months. Even under the best circumstances it takes months to get there, and the environment of deep space is tremendously harsh.
Sceptics think that despite its grand aspirations, Nasa remains far from getting humans there. Of the 43 robotic missions to Mars, including flybys, that have been attempted by four different countries, only 18 have been total successes.
Once a spunky startup, SpaceX, based in Hawthorne, California, has become a major force in the burgeoning space industry, with more than 4000 employees, a backlog of orders to launch commercial satellites and multi-billion dollar contracts with Nasa to fly cargo and eventually astronauts to the International Space Station on its Falcon 9 rocket.
Recently it pulled off feats once thought impossible - the vertical landings of its Falcon 9 rocket's first stage, one on a helicopter-like pad at Cape Canaveral and another on a ship in the ocean. The accomplishments of recovering and reusing rockets that were normally discarded after each flight could help lower the cost of spaceflight. And the successes have reignited interest in space, which has seemed dormant since the retirement of the space shuttle in 2011.
SpaceX is currently developing a new Dragon spacecraft that would be able to fly humans - and not just cargo - to the space station. It's also working on a more powerful rocket, the Falcon Heavy, which SpaceX says would become the world's most powerful rocket with thrust at liftoff equivalent to 18 747 jetliners.
"Falcon heavy was designed from the outset to carry humans into space and restores the possibility of flying missions with crew to the moon or Mars," SpaceX says on its website.
The rocket is slated to launch for the first time later this year from the Kennedy Space Center in Florida. SpaceX is leasing the historic launch pad 39A, which launched many of the Apollo and space shuttle missions.
For Musk, Mars has long been something of an obsession. Before he founded SpaceX, he was curious to know when Nasa planned to send humans there, so he checked the agency's website, he said at a conference a few years ago.
"Because, of course, there had to be a schedule," he said at the time. "And I couldn't find it. I thought the problem was me. Because, of course, it must be here somewhere on this website, but just well hidden. And it turned out it wasn't on the website at all. Which was shocking."
In an effort to drum up support for Nasa and galvanise the public, he decided to buy a rocket and send a greenhouse to Mars, which would be the furthest life had travelled and the first living thing on Mars. But buying a rocket proved to be too difficult and expensive, and Musk decided he'd build them on his own. Musk, the co-founder of PayPal, invested US$100 million of his own money into SpaceX.
Later this year, he is expected to lay out how SpaceX plans to fly humans to Mars. He has said he wants to colonise Mars so that humanity has a back-up plan in case anything should happen to Earth, such as an asteroid hitting it.
At a recent conference he said he wants to go to Mars for "the defensive reason of protecting the future of humanity, ensuring that the light of consciousness is not extinguished should some calamity befall Earth."
But what drives him most is what has drove generations of explorers before him, what Nasa long stood for, which was, simply, "that this would be an incredible adventure."