The Inspiration Mars team have said that the ideal crew for the mission will be, "two professional crew members - one man, one woman - flying as private US citizens."
Jane Poynter added that the crew members they sought should be a 'proven couple,' to help cope with the long trip.
The website for the mission added that, "method of crew selection and specific criteria to be announced at a later date."
More top news
Transport for London has revoked Uber's license in the capital.
ITV News understands the FA was told of a second separate investigation around Mark Sampson just months into his job as England head coach.
Metropolitan Police Commissioner Cressida Dick said the bomb could have caused deaths if it had fully detonated.