Quiz: what is the oldest manmade object in space?

Answer: this copper Lincoln penny, a 1909 US one-cent coin, launched into space on November 26, 2011, aboard the Curiosity Mars rover.

American geologists have long used Lincoln pennies as scale indicators in photographs. In homage to tradition, a 1909 one-cent coin is attached to Curiosity’s camera calibration target.

The second oldest human-made object in space, and until 2011 the oldest, is Vanguard 1, a satellite launched in 1958. It functioned until 1964, and is predicted to remain orbiting the Earth until the year 2198, when its orbit will have degraded so much that it falls in. It will presumably burn up in the atmosphere. But supposing any part reaches the ground and is picked up, by whom? Someone so technologically advanced we wouldn't recognise them, or by a cave dweller?

Came across this little nugget when researching space archaeology as part of a lecture I am due to give to an astronomy club next month.