A Soviet-era craft that took a dog into orbit could fetch $10 million.
A SOVIET space capsule stands ready for launch in the lobby of Sotheby's New York headquarters.
The Vostok 3KA-2, a giant rusty ball, orbited the Earth on March 25, 1961. It carried a life-size cosmonaut mannequin and a live dog, and landed two hours after launch in a snow-blanketed field about 1100 kilometres from Moscow.
Three weeks later, cosmonaut Yuri Gagarin climbed into an identical vehicle and became the first human to travel into outer space.
The test capsule could fetch as much as $US10 million when auctioned on April 12, the 50th anniversary of Gagarin's voyage.
Scorched and scratched on the outside, the ball looks cramped on the inside. Most of the interior is taken up by an ejection seat.
The architect of the Soviet space program, Sergei Korolev, tested five Vostok capsules before sending Gagarin. The four-legged cosmonaut on 3KA-2 was named Zvezdochka and fared better than some of her canine predecessors just by surviving. Footage played at Sotheby's shows the dog looking alert, if slightly out of breath, when taken from the capsule.
Her dummy companion, nicknamed Ivan Ivanovich, wore the same spacesuit Gagarin would wear, and was ejected from the capsule before landing, hitting the ground with a parachute.
The National Air and Space Museum has displayed Ivan Ivanovich as part of its Space Race exhibition since 1997. The item is on loan from businessman Ross Perot's foundation, which bought it at Sotheby's in 1993, Ms Lewis said. It fetched $US189,500.
The auction house offered the test capsule in 1996, with an estimate of $US800,000 to $US1 million. It didn't sell and was later acquired privately by an anonymous US businessman directly from the Russians, Mr Redden said.