Thursday, October 10, 2013
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A NASA spacecraft bound for Jupiter will buzz Earth
Wednesday (Oct. 9) to snag a gravity speed boost that will slingshot it toward
the largest planet in the solar system.
The Juno spacecraft will be
within 350 miles (560 kilometers) of Earth when it zooms by our planet at 3:21
p.m. EDT (1921 GMT). It will be passing over South Africa during its closest
approach to Earth.
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| An artists rendering depicts Nasa's Juno spacecraft wit Jupiter in the background. Juno will swing by Earth to gather the momentum it needs to arrive at Jupiter in 2016 |
Since
its 2011 launch on an unmanned Atlas 5 rocket, NASA's Juno mission to Jupiter has
followed a circuitous route toward Jupiter. This pass around Earth will give it
the boost it needs to make it the rest of the way to the solar system's largest
planet, accelerating the spacecraft from its current speed --78,000 mph
(126,000 km/h) with respect to the sun -- to a speed of 87,000 mph (140,000
km/h). [See photos of NASA's Juno mission to Jupiter]
"Juno is a large, massive
spacecraft," Juno mission principal investigator Scott Bolton with the
Southwest Research Institute in San Antonio, Texas, said in a statement.
"Even a large rocket couldn't provide enough propulsion to get us all the
way to Jupiter, so we are flying by the Earth for a gravity-assist that will
provide about 70 percent of the initial boost provided by the Atlas V 551
rocket. The gravity assist essentially provides as much propulsion as a second
rocket launch."
SwRI
officials released a video of the Juno probe's Earth flyby to describe how the spacecraft will
use Earth's gravity to help it reach Jupiter.
Although 97 percent of NASA staff
members are furloughed due to the government shutdown, Juno's mission-critical
Earth flyby operations have not been affected.
The
8,000-pound (3,267 kilograms) Juno probe is the first solar-powered spacecraft
to explore the outer solar system, and has three large solar arrays, each of
which is the size of a tractor-trailer. It also holds a titanium vault to
protect sensitive electronic equipment from the harsh environment around Jupiter.
"While we are primarily
using Earth as a means to get us to Jupiter, the flight team is also going to
check and calibrate Juno's science instruments," Bolton said in the
statement.
There's a bonus, too. Juno is
approaching Earth from the planet's sunlit side, which means it is in a prime
position to photograph its home planet from deep space.
"Juno will take
never-before-seen images of the Earth-Moon system, giving us a chance to see
what we look like from Mars or Jupiter," Bolton said.
The
$1.1 billion Juno spacecraft launched
in August 2011 and will reach the Jovian system on July 4, 2016. Juno will then
orbit around Jupiter for a full Earth year, studying the planet's atmosphere,
gravitational field and magnetic field with nine different science instruments,
according to the statement.
The mission is named after the
goddess Juno, from Greek and Roman mythology. In the myth, the god Jupiter (or
Zeus, as the Greeks would have it) used clouds to hide his mischievousness, but
his wife Juno was able to peer through the veil to see her husband's antics,
according to a NASA description.
Originally Published on Space.com
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