NASA's Juno to circle Jupiter for 'planetary recipe'
WASHINGTON, July 29, 2011 (AFP) - The US space agency plans to launch
next week a solar-powered spacecraft called Juno that will journey to
the gassy planet of Jupiter in search of how the huge, stormy giant was
formed.
The $1.1 billion unmanned orbiter is scheduled for launch on August 5
- the start of a five-year odyssey toward the solar system's most
massive planet in the hopes that it will be able to circle Jupiter for a
period of a year.
With its fiery red eye and a mass greater than all planets in the
solar system combined, excluding the Sun, Jupiter is intriguing to
astronomers because it is believed to be the first planet that took
shape around the Sun.
"After the Sun formed, it got the majority of the leftovers," said
Scott Bolton, Juno principal investigator and scientist at the Southwest
Research Institute in San Antonio, Texas.
"And that is why it is very interesting to us - if we want to go back
in time and understand where we came from and how the planets were made,
Jupiter holds this secret," he said.
"So we want to know that ingredient list. What we are really after is
discovering the recipe for making planets." Juno aims to get closer to
Jupiter than any other NASA spacecraft and will be the first to
undertake a polar orbit of the planet, said Bolton. In 1989, NASA
launched Galileo, an orbiter and probe that entered the planet's orbit
in 1995 and plunged into Jupiter in 2003, ending its life.
Other NASA spacecraft including Voyager 1 and 2, Ulysses and New
Horizons have done flybys of the fifth planet from the Sun. "We are
getting closer to Jupiter than any other spacecraft has gone in orbiting
Jupiter. We are only 5,000 kilometers (3,100 miles) above the cloud
tops," Bolton told reporters this week.
"And we are actually dipping down beneath the radiation belts which
is a very important thing for us because those radiation belts are the
the most hazardous region in the solar system other than going right to
the Sun itself."
Its trip to Jupiter, set to begin on August 5 when the launch window
opens at 11:34 am (1534 GMT), will not be a direct shot, according to
Jan Chodas, Juno project manager at NASA's Jet Propulsion Laboratory in
Pasadena, California.
"We launch from Earth in August, we swing out past the orbit of Mars,
we do a couple of deep space maneuvers to fire the engine," Chodas told
reporters.
Juno then heads back toward Earth, "and we do a flyby of Earth of
about 500 kilometers in October 2013, and then we slingshot ourselves
out towards Jupiter arriving in July 2016," she said. When it gets there
Juno will make use of a series of instruments, some of which were
provided by European space agency partners Italy, Belgium and France, to
learn about the workings of the planet and what is inside.
Two key experiments are to gauge how much water is in Jupiter and
whether the planet "has a core of heavy elements at the center, or
whether it is just gas all the way down," said Bolton.
Scientists also hope to learn more about Jupiter's magnetic fields
and its big red knot, a storm that has been raging for more than 300
years.
"One of the fundamental questions is how deep are the roots to that
red spot? How does it maintain itself for so long?" Bolton wondered.
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