* Juno to spend a year in polar orbit around Jupiter
* Journey to Jupiter will take 5 years
* Planet believed to hold clues to solar system formation
By Irene Klotz
CAPE CANAVERAL, Fla., Aug 5 An unmanned Atlas 5
rocket blasted off from Cape Canaveral Air Force Station on
Friday, sending a robotic scout on its way to Jupiter to sniff
out details about how the solar system formed.
The rocket carrying NASA's Juno spacecraft lifted off at
12:25 p.m. (1625 GMT), the first step in a five-year,
445-million mile (716-million km) journey to the largest planet
in the solar system.
Launch was delayed almost an hour while United Launch
Alliance, a Boeing (BA.N)-Lockheed Martin (LMT.N) joint venture
that builds and flies Atlas and Delta rockets for NASA, the
military and commercial customers, fixed a technical problem
with ground support equipment that supplies a helium purge to
Upon arrival in July 2016, Juno is to spend a year in an
unprecedented polar orbit around the giant planet, measuring
its water content, mapping its magnetic fields and searching
for signs of a solid core.
With more than twice the mass than all its sibling planets
combined, Jupiter is believed to hold a key piece to the puzzle
of how the planets formed some 4.65 billion years ago from the
gas and dust left over after the birth of the sun.
"We're really looking for the recipe for planet formation,"
said Juno lead scientist Scott Bolton, with the Southwest
Research Institute in San Antonio, Texas.
"We're going after the ingredients of Jupiter by getting
the water abundance as well as very precise measurements of the
gravity field that will help us understand whether there's a
core of heavy elements or a core of rocks in the middle of
Jupiter," he said.
The measurements will help scientists discriminate among
theories about what the early solar system looked like and how
Jupiter, believed to be the first planet to form, was created.
To make its observations, Juno will soar as close as 3,100
miles (5,000 km) above Jupiter's cloud tops, the first
spacecraft to fly inside the planet's radiation belts.
With its sensitive electronics housed in a vault of
titanium, Juno should last through 33 orbits around Jupiter,
which is about a year on Earth. Its last maneuver will be a
suicidal plunge into the planet's thick atmosphere, which will
incinerate the probe to avoid possible contamination of
Jupiter's water-bearing moons.
Now that NASA has retired its shuttle fleet, the U.S. space
spotlight could shift toward the robotic probes and
observatories have brought the biggest leaps toward
understanding the cosmos. [ID:nN1E7730GW]
The Juno mission is the second in NASA's lower-cost,
scientist-led New Frontiers program, and it was accomplished on
schedule and within its $1.1 billion budget.
The spacecraft was built by Lockheed Martin Astronautics of
In addition to launching science probes and other
satellites, United Launch Alliance is in the process of
certifying its Atlas 5 rockets to fly astronauts to the
International Space Station, one of several possible commercial
rockets contending to replace NASA's now-retired space shuttle
(Editing by Jane Sutton and Doina Chiacu)