The aim of the 17 month-long Mars500 project was to study the physical and psychological effects that the much longer journeytoMars might have on future astronauts.
That number includes the cost of the actual Mars probe and its launch, as well as the cost of the NASA crew handling its journeytoMars for almost a year before it started transmitting.
But Mr Aldrin disagreed with the view that astronauts should test capabilities for a long-duration flight on the Moon before attempting a journeytoMars.
The radiation exposure from a Marsjourney is similar to getting a full-body CT scan every five or six days, said lead researcher Cary Zeitlin of the Southwest Research Institute in Boulder, Colo.