The world's most famous moon walker is to skip a Nasa event next week commemorating the 40th anniversary of the moon landing. The notoriously shy Neil Armstrong, the first of only a dozen men to set foot on the Earth's nearest neighbour, is counting on Apollo 11 shipmate Buzz Aldrin to relive his "one small step" for a worldwide audience.

Armstrong is said to be deeply suspicious of fans and of the press. Instead, Aldrin will be joined on Monday at Nasa's Washington headquarters by Eugene Cernan, one of the last astronauts to visit the moon, and other Nasa astronauts.

Armstrong is due to appear on Sunday night at an event at Washington's Smithsonian Institution, where he is expected to give a 15-minute lecture. But he is unlikely to satisfy the world's desire to hear him speak about his brief jaunt across the lunar surface four decades ago.

"He will not be doing interviews or photos," said Isabel Lara, a spokeswoman for the Smithsonian. Nor will he be signing autographs, being reportedly suspicious of souvenir hunters since he discovered in 2005 that his Ohio barber had sold some of his hair to a collector for $3,000.

Armstrong's aversion to the spotlight could have played a part in his selection for the historic role.

According to his biographer James Hansen, Nasa threw out existing protocol that would have had Aldrin, the lunar lander pilot, as first out of the craft and on to the moon.

Nasa chiefs predicted that the first person on the moon would have to bear the burden of lifetime fame, and granted the privilege to the comparatively unassuming Armstrong. Michael Collins, meanwhile, remained in the stifling command module, hurtling around the moon and preparing at an instant's notice to initiate one of 18 rescue procedures, should something fail on the surface below.

Nasa has a number of events planned to mark the anniversary, which it hopes will bolster flagging public support for new investment in its space programme. Tomorrow, the 40th anniversary of the Apollo 11 launch, the US space agency is showing new broadcast-quality film of Aldrin and Armstrong's lunar excursion, including footage said to have been locked away in Nasa storage since the event.

A new website, wechoosethemoon.org, will recreate Armstrong's first steps and track the capsule's route from Earth to the moon.

The space shuttle programme, which has claimed the lives of 14 astronauts - 11 more than the Apollo programme - is slated for retirement next year.

Barack Obama has shown little enthusiasm in public for the shuttle's replacement, Constellation, which Nasa planners hope will return people to the moon by 2020.