http://spaceprojects.arc.nasa.gov/Space_Projects/pioneer/PNStat.html
STATUS UPDATED: 14 December 1999
Pioneer 10
(Launched 2 March 1972)
Distance from Sun (1 December 1999): 74.03 AU Speed relative to the Sun: 12.24 km/sec (27,380 mph) Distance from Earth: 10.95 billion kilometers (6.804 billion miles) Round-trip Light Time: 20 hours 17 minutes
PIONEER 10 HONORED BY STAMP!
On November 18, the US Postal Service issued a stamp commemorating the Pioneer 10 spacecraft. It was selected as one of the 15 icons for the decade of the 1970s as part of its Celebrate the Century postage stamp series.
The US Postal Service consulted with the Pioneer Project Manger to ensure its accuracy.
The following inscription was chosen for the stamp: Launched March 1972, "Pioneer 10" was the first spacecraft to travel to an outer planet, providing data and images of Jupiter. Eleven years later, it became the first man-made object to leave the solar system.
You can see an image of the new Pioneer 10 stamp here:
http://www.stampsonline.com/gallery/99/pioneer.htm
This is not the first time the US has commemorated Pioneer 10 on one of its stamps. They also did it in 1974. See this Web page for details and the image of that Pioneer stamp:
http://ails.arc.nasa.gov/Images/Ames/AC74-9009.html
Larry