Apollo 11 crew planned for their death before leaving on moon mission

The first men to walk on the Moon were feted as heroes and praised as pioneers when they set off for the moon in 1969, but memorabilia to be sold commemorating the mission's 40th anniversary revealed that the three astronauts secretly feared they might be on a one-way ticket, The Telegraph reports.

With insurance companies unwilling to cover their treacherous venture, and aware that government compensation in the event of their demise could be modest, Neil Armstrong, Buzz Aldrin and Michael Collins dreamed up an idea for securing their loved ones' futures: autographed first-day covers.

One of the signed envelopes - bearing the Apollo 11 mission emblem and postmarked at Kennedy Space Centre, Florida, on July 16, 1969, the day of the launch - is among 400 lots going under the hammer in a sale of rare space memorabilia at Bonhams auction house in New York.

"Since we were unable to obtain adequate life insurance due to the high risk nature of being an astronaut, we signed this group of covers and evenly distributed them to our families for safe keeping while we performed our mission," explained Buzz Aldrin, 79, in an accompanying letter certifying authenticity.

"If an unfortunate event prevented our safe return, the covers would have provided a limited financial means of support to our families."

In his subsequent written account, Aldrin reminisced: "The lunar surface was indeed desolate, but had a striking beauty all its own."

The auction is expected to draw bidding from space enthusiasts and collectors around the world, and raise at least 1.5 million dollars

"We have already had a lot of interest from people, both stateside and internationally," said Bonhams specialist Christina Geiger.

"Much of the material comes directly from the collections of various astronauts and there's certainly the feeling that they were holding back on some of their better material for the 40th anniversary of the lunar landing."