A rocket engine from the experimental aircraft North American X-15 is set to draw global attention at a January 11-13 auction in California.
The remarkable consignment is expected to sell for between $150,000-250,000. It would have cost the US government a "few million dollars" from new, according to the auction house.
The North American X-15 was part of the US Air Force and NASA's X-plane series during the early 1960s. Breaking many altitude and speed records at the time, the aircraft still holds the official world record for the fastest speed ever reached by a manned aircraft.
It was also the world's first operational spaceplane, after first reaching space in 1962/1963. Adding to its appeal even further are the legendary pilots who flew it, including Neil Armstrong, Scott Crossfield and Joseph H Engle.
The engine itself was the first large man-rated rocket engine that could be throttled and deliver 57,000 pounds of thrust. Fed by liquid oxygen and anhydrous ammonia, it measures 5 feet in length and weighs almost 500 pounds. It is believed to be the only example in private hands and may never come to the market again.
Also selling is a US flag flown to the Moon by the Apollo 11 crew, which is attached to a colour certificate. Signed by Neil Armstrong and Buzz Aldrin, with an autopen signature from Michael Collins, it will be sold for $20,000- 25,000.