Two former top NASA officials unveiled plans Thursday to sell manned flights to the moon by the end of the decade, in an announcement 40 years after the last human set foot there. Spaceflight, long the province of national governments, has moved toward increased commercialisation in recent years, with private companies for the first time successfully launching rockets into orbit.

The US space agency, in the hopes of keeping costs down, even retired its space shuttles in 2011, choosing instead to pay for space on Russian craft - and, more recently, on one built and operated by SpaceX to get people and supplies to the International Space Station.

But with ever shrinking budgets, manned flights beyond Earth's orbit have been put on hold, with the US space agency relying on robots to do its exploring of the rest of the solar system. The Golden Spike Company, its name a reference to the spike that completed the first railway to traverse the United States, aims to take part in the new wave of private spaceflight, as well as open up new frontiers by getting humans back into outer space. The company estimates it will cost $1.5 billion for a round-trip expedition to the moon, a price tag it says is roughly equivalent to the amount government-funded space programs spend to send robots there now.

Copyright Agence France-Presse, 2012