In March 1972, the Pioneer 10 space probe was
launched on the first flyby mission to explore the planet Jupiter.
It was followed by its sister craft Pioneer 11 in April 1973.
Because of the tremendous gravitational pull of Jupiter, scientists
calculated that the flyby would accelerate the probes like a giant
slingshot and hurl them out of the Solar System. Realising that
they had a chance for the most expensive message in a bottle ever
conceived, NASA decided to tack a small plaque of anodised aluminium
as a message to any space-faring race that might stumble across the
probes. The plaque was designed by Dr. Carl Sagan and Dr. Frank
Drake and drawn by Linda Salzman Sagan, and formed a simple greeting
that said little more than "Hello. We sent this. Here is
roughly where we are."
Not the most exciting prose, but what can you
expect from a postcard?
Pioneer 10 & 11 were not only the first man-made
objects to leave the Solar System, they were also the first to leave
the realm of Future Past. It was the first "time capsule" after
the watershed of the space age, but how things were changing wouldn't
be evident until the next longer message was sent.