Juno Ready to Launch to Jupiter

The Juno spacecraft will soon be on its way to Jupiter on a mission to look deep beneath the planet's swirling curtain of clouds to find out what lies beneath. The answer might confirm theories about how the solar system formed, or it may change everything we thought we knew.

"The special thing about Juno is we're really looking at one of the first steps, the earliest time in our solar system's history," said Scott Bolton, the principal investigator for the Juno mission. "Right after the sun formed, what happened that allowed the planets to form and why are the planets a slightly different composition than the sun?"

Starting the 4-ton spacecraft on its five-year journey to the largest planet in the solar system is the job of a United Launch Alliance Atlas V equipped with five solid-fueled boosters. Even with that much power, Juno will still require a flyby of Earth to get up enough energy to swing out to Jupiter.

With three 34-foot-long solar arrays and a high-gain antenna in the middle, the spacecraft is reminiscent of a windmill. It even spins slowly as it goes through its mission. Those arrays will be the sole power source for Juno as it conducts its mission, a first for a spacecraft headed beyond the asteroid belt between Mars and Jupiter.

The Atlas V has proven a reliable option for NASA's Launch Services Program, or LSP, the organization that oversees NASA launches and chooses the best launchers for different spacecraft.

"It's flown 28 times, pretty challenging missions, pretty challenging payloads," said Omar Baez, launch director for Juno. "It's got a heritage that goes back to the Atlas I in some of the components and in the upper stage, so it's an evolution of a family in its current configuration and shape and form. I'd say it's pretty robust."

The spacecraft is to lift off at 11:34 a.m. on Aug. 5 from Space Launch Complex 41 at Cape Canaveral Air Force Station in Florida. The mission faces a limited launch window to get off Earth before Jupiter's orbit took it out of alignment.

"Juno only has a 22-day launch window, or else we're down for another 13 months until our next opportunity," said John Calvert, mission manager for Juno. "So it's those kinds of challenges with making sure you do all the little things necessary to maximize the opportunities you get for those 22 days."

Juno to Show Jupiter's Magnetic Field in High-Def

When it comes to magnetic fields, Jupiter is the ultimate muscle car. It's endowed with the biggest, brawniest field of any planet in the solar system, powered by a monster engine under the hood.

Figuring out how this mighty engine, or dynamo, works is one goal of NASA's Juno mission, which is scheduled to begin its five-year, 400-million-mile voyage to Jupiter in August 2011. Juno will orbit the planet for about a year, investigating its origin and evolution with eight instruments to probe its internal structure and gravity field, measure water and ammonia in its atmosphere, map its powerful magnetic field and observe its intense auroras.

The magnetic field studies will be the job of Juno's twin magnetometers, designed and built at NASA's Goddard Space Flight Center in Greenbelt, Md. They will measure the field's magnitude and direction with greater accuracy than any previous instrument, revealing it for the first time in high-def.

"Valuable information about Jupiter’s magnetic field was gathered by the Pioneer 10 and 11 missions in the early 1970s and Voyagers 1 and 2 in the late '70s," says NASA Goddard's Jack Connerney, Juno's deputy principal investigator and head of the magnetometer team. Connerney is collaborating with the mission's principal investigator, Scott Bolton, at the Southwest Research Institute in San Antonio, Texas. "But previous spacecraft orbited among Jupiter's moons; Juno, a polar orbiter, will be the first magnetic mapping mission to Jupiter."

"Mapping Jupiter's magnetic field is one of the very few ways available to learn about Jupiter's deep internal structure," says Juno's project scientist, Steven Levin of NASA's Jet Propulsion Laboratory in Pasadena, Calif., which manages the Juno mission. That's because Jupiter's atmosphere is compressed so much by its powerful gravity field that it becomes impenetrable to most sensing techniques.

Juno Blanket Check

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Juno mission for the principal investigator, Scott Bolton, of Southwest Research Institute in San Antonio.

PASADENA, Calif. – As the Juno spacecraft is elevated by a rotation fixture, a technician at Astrotech's payload processing facility in Titusville, Fla., examines the installation of blankets on the aft deck. The image was taken on June 16, 2011.

Juno is scheduled to launch aboard a United Launch Alliance Atlas V rocket from Cape Canaveral, Fla. on Aug. 5. The solar-powered spacecraft will orbit Jupiter's poles 33 times to find out more about the gas giant's origins, structure, atmosphere and magnetosphere and investigate the existence of a solid planetary core.

Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States and NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Juno mission for the principal investigator, Scott Bolton, of Southwest Research Institute in San Antonio. The Juno mission is part of the New Frontiers Program managed at NASA's Marshall Space Flight Center in Huntsville, Ala. Lockheed Martin Space Systems, Denver, built the spacecraft. Launch management for the mission is the responsibility of NASA's Launch Services Program at the Kennedy Space Center in Florida. JPL is a division of the California Institute of Technology in Pasadena.