NASA's solar-powered Juno spacecraft, the centerpiece of a $1.1 billion mission to Jupiter, was mounted atop an Atlas 5 rocket Wednesday, setting the stage for launch Aug. 5 on a five-year voyage to the solar system's largest planet.
Once in orbit around Jupiter's poles, Juno's instruments will precisely map the planet's gravitational and magnetic fields, probe its turbulent atmosphere and hidden interior and study the mechanisms responsible for its powerhouse auroras, the strongest in the solar system.
"Jupiter probably formed first, it's the largest of all the planets, in fact it's got more material in it than all the rest of the solar system combined," Scott Bolton, Juno principal investigator at the Southwest Research Institute in San Antonio, Texas, told reporters Wednesday. "If I took everything in the solar system (except the sun), it could all fit inside Jupiter.
"So after the sun formed, (Jupiter) got the majority of the leftovers. And that's why it's very interesting to us. If we want to go back in time and understand where we came from and how the planets were made, Jupiter holds this secret, because it got most of the leftovers after the sun formed, and we want to know that ingredient list. What we're really after is discovering the recipe for making planets."