A NASA spaceprobe is currently racing on its way to Jupiter. Solar-powered Juno is a $700 million “budget” mission but it carries with it the prospect of unlocking some fundamental secrets about how the Solar System formed. 

How Juno will appear in orbit around Jupiter (NASA)

Juno, named after Roman god Jupiter’s mythical wife, blasted off from Cape Canaveral, Florida, on August 5. It will take the long way to reach its target, gaining momentum from flybys of other planets, including Earth, before it gets to the largest planet in 2016.

Jupiter is interesting for two major reasons. Firstly, it is bigger than everything else in the Solar System, after the Sun, put together which is why we hope to learn about how the Sun’s family condensed from a cloud of gas and dust four billion years ago.

Secondly, giant gas planets like Jupiter appear to be common in the galaxy with many hundreds having been discovered orbiting other stars. Often these are “hot Jupiters” whereas our own planetary king seems to have evolved in a cold, remote region of space.

Juno will be in a polar orbit around Jupiter, braving its ferocious radiation belts and probing deep into the clouds, making the mission quite different to that of Galileo, the last NASA probe to orbit the planet from 1995 to 2003.

I have written a lot more about the Juno mission elsewhere so will not go into more detail here. You can see my article in print in the August 2011 issue of BBC Sky at Night magazine, or read another fuller account online at SEN TV, a great new website for space enthusiasts.