BOSTON, MASS.- A checklist worn by the last man to walk on the Moon could fetch more than US $400,000 when it goes under the hammer.

The Apollo 17 checklist was strapped to astronaut Gene Cernan’s wrist during the longest single moonwalk of NASA’s Apollo programme in December 1972.

The historic item, which still bears traces of lunar dust, carries an auction estimate of US $400,000+ and is being offered in a sale closing on October 22.

Cernan wore the small spiral-bound booklet on his left wrist as he explored the lunar surface alongside fellow astronaut Harrison Schmitt during the mission’s second moonwalk.

The pair spent seven hours, 37 minutes and 22 seconds outside their lunar module, Challenger, travelling approximately 12 miles (19.5km) in their lunar rover.

The checklist also contains handwritten instructions for an improvised repair that proved important to the crew’s exploration.

During an earlier moonwalk, Cernan had accidentally torn off the rover’s right rear mudguard with his spacesuit.

Without the guard, the vehicle’s wheels sprayed abrasive lunar dust over the astronauts, their equipment and cameras.

Engineers at Mission Control devised a makeshift replacement using spare lunar maps, brackets and grey tape.

Cernan wrote the repair instructions on the back page of his checklist before the astronauts assembled a replacement mudguard from laminated maps, tape and clamps.

The repair protected the crew and their vehicle for the remainder of the mission. The improvised mudguard is now preserved at the National Air and Space Museum.

During the same moonwalk, Schmitt discovered unusual orange-coloured soil near Shorty Crater, one of the Apollo programme’s significant geological discoveries.

The checklist measures just 3.5 by 2.5 inches and contains 25 double-sided leaves, including lunar maps, geological instructions and spacesuit procedures.

Several pages retain grey smudges consistent with exposure to lunar dust.

A signed letter from Cernan, dated December 31, 2013, confirms that the checklist was carried and used extensively during his second moonwalk.

He described it as “one of the rarest of Apollo artifacts” and confirmed that NASA returned it to him in 1973.

The checklist is among the highlights of RR Auction’s sale, which also features several other items associated with historic space missions.

An 18-carat gold Omega Speedmaster Apollo 11 commemorative watch from the personal collection of Apollo 12 astronaut Alan Bean is estimated at US $150,000+.

Another Omega Speedmaster chronograph, flown aboard the Mir space station and described as having spent 365 days in space, carries an estimate of US $60,000+.

Also being offered is an Apollo 12 lunar module-flown stowage bag from Bean’s collection, estimated at US $45,000+.

Other highlights include an Apollo 11 crew-signed quarantine cover carried to the Moon, estimated at US $30,000+, and a complete microfilm King James Bible carried to the lunar surface aboard Apollo 14, estimated at US $40,000+.

RR Auction’s Space Exploration sale closes on October 22.