Juno Will Place Spacecraft In High Elliptical Polar Orbit
NASA is officially moving forward on a mission to conduct an
unprecedented, in-depth study of Jupiter. Called Juno, the mission
will be the first in which a spacecraft is placed in a highly
elliptical polar orbit around the giant planet to understand its
formation, evolution and structure. Underneath its dense cloud
cover, Jupiter safeguards secrets to the fundamental processes and
conditions that governed our early solar system.
"Jupiter is the archetype of giant planets in our solar system
and formed very early, capturing most of the material left after
the sun formed," said Scott Bolton, Juno principal investigator
from the Southwest Research Institute in San Antonio. "Unlike
Earth, Jupiter's giant mass allowed it to hold onto its original
composition, providing us with a way of tracing our solar system's
history."
The spacecraft is scheduled to launch aboard an Atlas rocket
from Cape Canaveral, FL in August 2011, reaching Jupiter in 2016.
The spacecraft will orbit Jupiter 32 times, skimming about 3,000
miles over the planet's cloud tops for approximately one year. The
mission will be the first solar powered spacecraft designed to
operate despite the great distance from the sun.
"Jupiter is more than 644 million kilometers (400 million miles)
from the sun or five times further than Earth," Bolton said. "Juno
is engineered to be extremely energy efficient."
The spacecraft will use a camera and nine science instruments to
study the hidden world beneath Jupiter's colorful clouds. The suite
of science instruments will investigate the existence of an
ice-rock core, Jupiter's intense magnetic field, water and ammonia
clouds in the deep atmosphere, and explore the planet's aurora
borealis.
"In Greek and Roman mythology, Jupiter's wife Juno peered
through Jupiter's veil of clouds to watch over her husband's
mischief," said Professor Toby Owen, co-investigator at the
University of Hawaii in Honolulu. "Our Juno looks through Jupiter's
clouds to see what the planet is up to, not seeking signs of
misbehavior, but searching for whispers of water, the ultimate
essence of life."
Understanding the formation of Jupiter is essential to
understanding the processes that led to the development of the rest
of our solar system and what the conditions were that led to Earth
and humankind. Similar to the sun, Jupiter is composed mostly of
hydrogen and helium. A small percentage of the planet is composed
of heavier elements. However, Jupiter has a larger percentage of
these heavier elements than the sun.
"Juno's extraordinarily accurate determination of the gravity
and magnetic fields of Jupiter will enable us to understand what is
going on deep down in the planet," said Professor Dave Stevenson,
co-investigator at the California Institute of Technology in
Pasadena. "These and other measurements will inform us about how
Jupiter's constituents are distributed, how Jupiter formed and how
it evolved, which is a central part of our growing understanding of
the nature of our solar system."
Deep in Jupiter's atmosphere, under great pressure, hydrogen gas
is squeezed into a fluid known as metallic hydrogen. At these great
depths, the hydrogen acts like an electrically conducting metal
which is believed to be the source of the planet's intense magnetic
field. Jupiter also may have a rocky solid core at the
center.
"Juno gives us a fantastic opportunity to get a picture of the
structure of Jupiter in a way never before possible," said James
Green, director of NASA's Planetary Division at NASA Headquarters
in Washington. "It will allow us to take a giant step forward in
our understanding on how giant planets form and the role that plays
in putting the rest of the solar system together. "
The Juno mission is the second spacecraft designed under NASA's
New Frontiers Program. The first was the Pluto New Horizons
mission, launched in January 2006 and scheduled to reach Pluto's
moon Charon in 2015. The program provides opportunities to carry
out several medium-class missions identified as top priority
objectives in the Decadal Solar System Exploration Survey,
conducted by the Space Studies Board of the National Research
Council in Washington.