The robotic explorer, named Juno, are on an unmanned rocket in Cape Canaveral, Florida. Liftoff is scheduled for 11:34 (1534 GMT) Friday.
Juno takes five years to reach Jupiter, the largest planet in the solar system. The spacecraft will be powered by three huge solar panels. It will be the farthest any solar boat has never traveled. Jupiter previous probes have been based on nuclear energy.
Jupiter is considered the oldest planet in the solar system. Astronomers expect to find the recipe for making planets, the discovery of the ingredients of the gas giant. Juno will spend at least one years circling the poles of Jupiter.