January 18, 2007 5:13 PM PST
Pluto mission to reveal Jupiter's secrets
The New Horizons spacecraft will arrive at its closest point to Jupiter on February 28. While swinging by the planet, it will make several hundred observations of Jupiter, its moons and ring system before picking up speed and heading on to examine the dwarf planet Pluto and Charon, one of its moons.
New Horizons, which NASA says is the fastest spacecraft ever launched, made its debut in space last year. After launching on January 19, the spacecraft reached Earth's moon in just nine hours and Mars by April. If it makes its expected arrival date at Jupiter, it will have traveled hundreds of millions of miles from Earth within 13 months, said Glen Fountain, project manager for New Horizons at the Johns Hopkins University Applied Physics Laboratory
After examining Jupiter, scientists will leverage the massive planet's gravity to increase New Horizons' speed, accelerating it away from the sun to achieve a speed of 52,000 mph. This will essentially hurl the spacecraft on a trajectory toward Pluto, said Fountain.
While other spacecraft have taken passes by Jupiter, Cassini didn't get as close as New Horizons will, and Galileo was not capable of taking the same kind of detailed images planned for this trip, according to NASA.
"We are going to produce some stunning data sets, and we can't wait to get them on the ground," said Alan Stern, principal investigator for New Horizons and executive director of the Space Science and Engineering Division at the Southwest Research Institute.
New Horizons' trajectory will take it along about a quarter of Jupiter's magnetotail--a part of its magnetosphere that stretches out away from the sun. It's a place where no spacecraft has traveled before, said James L. Green, acting director of the Planetary Science Division at NASA.
While at Jupiter, New Horizons will examine the planet's "Great Red Spot," the famous storm that is roughly twice the size of Earth. Scientists will measure cloud levels and make a 3D movie of the circulation in the complex area. Surprises about the area have already been discovered by New Horizons, according to NASA.
"The region northwest of the Great Red Spot looks calmer than NASA scientists had expected, and the atmosphere seems to be clearing," said Stern.
The spacecraft will also study Jupiter's "Little Red Spot," which has seen some change in recent years as well. New Horizons will examine it 30 times closer than previously possible, producing the most detailed pictures that have ever been taken of it.
The project will also study Jupiter's four moons, Io, Ganymede, Callisto and Europa. Io, which is similar in size to Earth's moon but vastly different in makeup, is heated by Jupiter and puts out as much heat as the Earth itself, with enormous volcanic plumes jetting out and producing a thin plasma atmosphere. Europa is thought to have a liquid ocean beneath its ice shell. NASA is timing the spacecraft to examine enormous circular grooves covering half Europa's diameter that can only be seen when the sun is shining at the correct angle, according to Stern. If the New Horizons trajectory remains on schedule, it will get a look at a star passing behind Europa.
The spacecraft will also be used to conduct the most comprehensive study of Jupiter's ring system ever, taking 3D measurements of the rings' thicknesses as well as any satellites orbiting in them.
The space agency has not yet decided whether it will make the first live views of the Jupiter pass available to the public, according to the press conference moderator.
After passing by Jupiter, New Horizons will pass the orbits of Saturn, Uranus and Neptune, arriving at Pluto in 2015. After five months of studying the geology, surface and atmospheric composition and temperatures of Pluto and its three moons, the spacecraft may study one of the smaller bodies in the Kuiper Belt, the region beyond Neptune. All told, the spacecraft could travel up to 50 astronomical units (almost 4.7 billion miles) by 2020, according to Fountain.
"Going to the frontier is something very new," Stern said. "This is a whole new zone of the solar system where the giant planets lie. We think it's very exciting."