For the first time in fifteen years, there is a probe inbound to Jupiter*. On Friday, after a last-minute hold at t-4 minutes, NASA's Juno probe left Kennedy Space Center at 12:25pm aboard a Atlas V heavy-lift booster.
Two years from now, the probe will pass very close to Earth for a gravity assist. Via this quirk of orbital mechanics, it will steal some orbital momentum from the Earth and reach Jupiter in just three more years.
It's set to study Jupiter's water ratio and core mass - which will help determine how it formed - and precisely map its gravitational and magnetic fields. It will also study the polar components of Jupiter's magnetosphere and the massive auroras it creates. However, the main purpose of the mission is to better understand the cloud systems that cloak Jupiter. In fact, the mission is names for the goddess Juno, wife of Jupiter, who could see through his veil of clouds - just like the probe will.
It's the first solar-powered probe to reach the gas giants, made possible by new advances in solar panels. Previous craft, like Galileo (the previous Jupiter mission) used radioactive thermal generators, which generate more power than solar panels. Juno's instruments are designed to use less current than previous probes.
Many spacecraft carry an interesting tribute. Many have CDs containing names of project members; the Voyagers carried the famous golden records. Juno is carrying three Lego minifigures: Jupiter, Juno, and Galileo.
RIP Chuck Berry
3 days ago