Deep Impact was an astronomical experiment, for sure.
All you've got to do is send a chunk of metal towards Alpha Centauri, and in a few thousand years, someone else will watch what happens when it hits. And if you're lucky, they'll include you as a middle author :-)
LOL! :-)
I had the fortune of being in the mission control room at JPL for the Magellan launch. (My voice is recorded as saying "go for launch"). :-) My two seconds of fame. LOL!