The recent launch of the Curiosity Mars rover has quietly broken the record for oldest human-made object in space, and instantly pulled numismatics, the study of coinage, into the Space Age.
American geologists have long used copper Lincoln pennies as scale indicators in photographs. All the Mars rover missions are geology projects conducted at a distance. And so, as a homage to professional geology tradition, a 1909 one-cent coin is attached to Curiosity’s camera calibration target.
Being over a hundred years old, the coin is from a time sufficiently far from the present that industrial and conflict archaeologists already routinely excavate and document its remains. As far as I know, this is the first time that an antique is launched into space (disregarding stuff astronauts have brought into orbit and then back home again).
Update 15 Feb: Long-time Aard regular Lassi Hippeläinen points out that in 1999, some cremated remains of planetary geologist Eugene Shoemaker were sent to the Moon, and he was born in 1928. In my opinion, burnt human bones do qualify as artefacts, but they were made at cremation, not when Shoemaker’s original baby skeleton formed.