Pluto-Bound Spacecraft to Nab Speed Boost in Jupiter Flyby

NASA's New Horizons snapped this view of Jupiter and its volcanic moon Io in early January 2007. CREDIT: NASA/JHU/APL.

A NASA probe hurtling towards Pluto will hit the accelerator next month when it flies past the planetary giant Jupiter.

The New Horizons spacecraft is due to make its closest pass by Jupiter on Feb. 28 and add another 9,000 miles (14,484 kilometers) per hour to its velocity as it speeds out towards a rendezvous with Pluto in July 2015 [image].

"This is a big test for our mission," said Alan Stern, NASA's New Horizons principal investigator at the Southwest Research Institute in Boulder, Colorado. "We're actually beginning to get data, important scientific data, which my team is going to be rabid to work with as soon as we get it on the ground."

New Horizons' swing past Jupiter is a rehearsal of sorts for its ultimate flyby of Pluto and its moons in 2015 [image]. The probe will not only study Jupiter's turbulent atmosphere, but scan its auroras, rings, moons and - for the first time ever - the planet's trailing magnetic field.

"There is no mission plan to do another flyby like this of the Jupiter system," said Stern, who spoke during a Thursday mission briefing at NASA's Washington, D.C. headquarters.

Pit Stop to Pluto

NASA launched its New Horizons mission one year ago Friday on what the space agency has billed as its fastest flight to the outer rim of the solar system [video].

With its seven instruments, New Horizons is designed to study Pluto, its three moons - Charon, Hydra and Nix - and distant icy objects in the Kuiper Belt that lie beyond the orbit of Neptune. Those objects, researchers hope, contain 4.5 billion-year-old traces of the solar system's building blocks.

What New Horizons finds at Pluto and in the Kuiper Belt should help astronomers answer "some fundamental questions about the origin of the solar system," James Green, acting director of NASA's Solar System division, during the briefing.

The probe is currently 41 million miles (65 million kilometers) from Jupiter and closing at a speed of about 44,268 miles (71,242 kilometers) per hour.

At its closest approach, New Horizons will swing within 1.7 million miles (2.3 million kilometers) of Jupiter to grab a gravity boost that will shave three years off its flight to Pluto, researchers said [image].

"We've designed this particular flyby to be a stress test on our spacecraft to work out the kinks," Stern added.

Jupiter's storms, moons and magnetotail

With 700 separate Jupiter system observations planned during its Jovian encounter, the New Horizons probe will be far from idle when it swings past the gas giant planet.

"We'll be making the most of this opportunity to learn a lot about Jupiter itself," said John Spencer, deputy chief of New Horizons' Jupiter encounter science team at SwRI.

New Horizons has already made an unexpected find within Jupiter's atmosphere. Its initial set of black and white images of the planet's notorious tempest the Great Red Spot taken earlier this month revealed that a turbulent region to the storm's northwest - as seen by the Cassini probe in 2000 - appears to have calmed.

"That region looks really quite cloud-free," Spencer said. "So that's not what we expected."

New Horizons will also provide a fresh look at Jupiter's four largest moons - volcanic Io, Europa, Ganymede and Callisto - as well as study the planet's auroras and hunt for new satellites within its faint rings, researchers said.

But for some, the highlight comes after the probe's flyby, when New Horizons will fly through Jupiter's magnetotail, the trailing portion of the planet's magnetic field that extends outward away from the Sun [image].

"No spacecraft has ever been there. We don't know what happens there," Spencer said of Jupiter's magnetotail. "It just so happens by good luck that the path to Pluto leads us right down the magnetotail."

Astronomers estimate Jupiter's magnetotail sweeps across six astronomical units - or six times the distance between the Earth and Sun - to reach the orbit of Saturn. One astronomical unit, or AU, is about 93 million miles (149 million kilometers).

"This is a whole new zone of the solar system," Stern said of New Horizons stomping grounds. "It opens up a window into the outer solar system and a window back in time 4.5 billion years to the birth of the planets."

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