Microchips on Stardust
Stardust was a comet sample return mission that was launched on February 7, 1999.
Microchip #1 was the result of a first name collection effort which ran from October to November 1997. 136,000 names were collected. The names on Microchip #2 (more than 1 million) were collected during May-August 1998.
Two copies of each chip were installed on the spacecraft (for a total of four chips). Two of the microchips (#1 & #2) are inside the Sample Return Capsule, and have returned back to Earth with the capsule on January 15, 2006. The other two chips are still on the spacecraft body and will remain in space forever.
You can find more
information about the microchips
about the microchips inside the Sample Return Capsule:
The path of spacecraft Stardust