The Inspiration Mars Foundation,  led by Dennis Tito, the first space tourist, will announce on Wednesday Feb. 27 a planned mission to Mars in 2018.

The mission would take advantage of a unique window of opportunity; the orbits of Earth and Mars will be closely aligned. The round-trip journey would start in January 2018 and take 501 days.

No details are available yet on how they will get there and whether a Mars landing is planned.

Speakers lined up for the press conference give some clues, says New Scientist. 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.