NASA’s most recent mission to Jupiter called Juno was launched this week with a crew of three. The three aren’t normal astronauts however, they are 3 Lego figures attached onto the spacecraft.
The figures are representations of the roman god Jupiter, his wife Juno, and Gallileo who was the first person to discover moons around jupiter, and for that matter around any other planet.
Jupiter is the largest planet in the solar system, and contains more mass than all the other planets combined, and so probably started forming before the other planets. Juno is going to study the atmosphere and magnetosphere of Jupiter to try and discover more about its composition and structure.
The figures should be going on a long journey of about 2.8 billion km, first on an orbit that sends them just outside Mars, then getting an additional kick from earth's gravity in 2013, and arriving at Jupiter in 2016, when Juno can start its mission.
Unfortunately for any Jovian children who may come across these lego men, they are made out of solid chunks of aluminium, and aren't articulated, so playing with them might be rather dull. This is probably because the plastics used to make normal lego-men haven't been approved for use on space missions and might emit substances which could fog up a lens, or interfere with an instrument, but the idea is to inspire children on earth by taking something they associate with on an amazing journey.