Jacob Aron, reporter
An organisation led by Dennis Tito, the first ever space tourist, has announced its intention to launch a mission to Mars in 2018 - though just who or what will be on board remains to be seen.
Tito paid $20 million to be the first paying guest of the International Space Station in 2001, marking the start of the space tourism industry. Now he has formed the Inspiration Mars Foundation, which plans to launch "an historic journey to Mars and back in 501 days", according to an announcement in advance of a press conference next Wednesday.
The announcement does not give many more details of the mission, but other speakers lined up for the press conference give some clues. Jonathan Clark of the National Space Biomedical Research Institute in Houston, Texas, a former NASA crew surgeon and recent advisor on Felix Baumgartner's supersonic skydive from near the edge of space, will probably speak about the health risks of a long-term space mission, which hints at the possibility of a crewed mission.
Also speaking are Jane Poynter and Taber MacCallum of Paragon Space Development, a company with expertise in life support in extreme environments. The pair were both members of the Biosphere 2 mission, a controversial attempt at simulating a space colony two decades ago, and have previously proposed landing a greenhouse on the moon to grow flowers there.
Speculation ahead of the announcement is rife. Wired reckons the mission will aim to be crewed. NBC is more cautious, suggesting that the plan might be to put plants or animals on board instead, as pulling a crewed mission together in five years would be expensive and risky. The 2018 date is particularly favourable because the orbits of Earth and Mars will be closely aligned, but NASA recently scrubbed a launch that year in favour of a 2020 sequel to its successful Curiosity rover. Bottom line: it's hard to get to Mars in a hurry.
We also don't know whether the mission is meant to land on Mars or merely orbit the planet. Space Adventures, which booked Tito's ISS trip, has been selling moon fly-bys since 2005, though none has taken place so far. But even an uncrewed return mission to the surface of the Red Planet would make history if it brought Mars rocks back to Earth.
Also to be announced is just how Tito plans to get to Mars. The obvious answer is to use Space X's Red Dragon craft, a planned variant of the Dragon capsule that has already serviced the ISS. Space X founder Elon Musk has promised to deliver humans to Mars within a decade, so five years might be slightly short notice. We'll find out more on 27 February.