A 25-year manned Moon and Mars programme could cost around $500 billion, according to the chairman of the European Space Agency exploration directorate's senior advisory committee.
Speaking at the third workshop on international cooperation for sustainable exploration organised by ESA and Italian space agency ASI, advisory committee chairman Gerhard Haerendel, emeritus professor at the Max Planck Institute for Extraterrestrial Physics, says international cooperation is needed because of the cost.
Is the world ready for the cost of returning to the Moon
He cited various past cost estimates including the International Academy of Astronautics' 1993 project and a 1984 study by a member of the Wernher von Braun team, so pivotal to the US Apollo programme.
"My personal evaluation of the costs of a combined Moon and Mars exploration programme is €400 billion [$540 billion]. I got some support for this by an unofficial quotation of a study, supposedly by the Aerospace Corporation, which estimated costs of $500 billion," says Haerendel.
He believes it is not premature to openly discuss such large costs and that, by describing exploration as a global enterprise for all mankind, even an expensive programme could gain support.
As part of this joint exploration effort, Haerendel has advocated an international quarantine facility for samples of Mars soil brought back by ESA's proposed international Mars Sample Return mission in the 2020s.