Moves to get official backing to send Madonna into space have been blocked.
Madonna has recently played a concert in Moscow
The Russian parliament voted down a proposal to put the pop icon on the international space station in 2008.
Member Alexei Mitrofanov had said her involvement would guarantee the station international coverage and could potentially help future projects.
But despite the rejection, a spokesman for the Russian space agency said there were vacancies for $20m-a-head space tourists from 2009.
Mr Mitrofanov was quoted by the RIA-Novosti news agency as saying: "Because of the television possibilities, it would be a pretty serious event in the year of elections in the United States and Russia."
The same agency quoted space agency spokesman Igor Panarin as saying: "Taking into account her good physical preparedness and financial capabilities, the dream of [Madonna] Louise Ciccone of a space flight could be realized in 2009."
Madonna played before 35,000 people in Moscow on Tuesday night, despite religious protesters' threats to disrupt the concert.
Three private individuals have paid for the 10-day trips to the international space station.