Jupiter Science

New Horizons used the strong gravity of the massive planet Jupiter (320 times the mass of Earth) to boost it on its way to Pluto — but the flyby of Jupiter at a distance of 2.3 million kilometers (1.4 million miles) was also an opportunity to test the New Horizons instruments and do science at the same time.

3-D Generated Image of New Horizons Spacecraft in space.

Observations of the Jupiter system began about 60 days before the closest approach (on February 28, 2007) and ran for about 120 days after. Because the primary objective of the mission is to study Pluto and Charon, calibration and testing activities took precedence over the science activities in the Jupiter period. Indeed, since getting to Pluto is the number-one concern, making sure that the gravity assist was just right was vitally important. Key to the success of the gravity assist was ensuring that New Horizons flew exactly through the aim point near Jupiter, so that it would be sent off with a boost in speed and in the right direction for the encounter with Pluto eight and a half years later. This was a complete success.

Jupiter Flyby Geometry diagram

With the primary mission in mind, Jupiter encounter observations fall into three major categories:

Taking into account that the calibration, instrument testing, and optical navigation had the highest priority, as many science observations as possible were scheduled.

Science Priorities

The team divided Jupiter period science observations into four major categories:

1) Studies of Jupiter's atmospheric structure and storm behavior.
2) Observations to gather additional information on the major known moons/satellites of Jupiter including atmosphere, eclipse, global composition and/or feature maps for each major satellite.  
Images of the 4 moons
3) Investigation of ring composition and a search for additional Jupiter satellites within the ring structures.
4) Studies of Jovian magnetosphere via local measurements of charged particle fluxes and by remote sensing of auroral emissions.

The next NASA spacecraft to Jupiter is the second New Frontiers mission, Juno, which launced on August 5, 2011.