A NASA spacecraft
hurtling away from Earth has caught
the first glimpse of its distant destination: the dwarf planet Pluto.
The New
Horizons probe, set to swing by Pluto and its moons
in 2015, plucked the small planet from a star-filled image during a checkout
period using the spacecraft's long range camera [image].
"Finding Pluto
in this dense star field really was like trying to find a needle in a haystack,"
said New
Horizons principal investigator Alan Stern, of the Southwest Research
Institute in Boulder, Colorado, in a statement.
Stern said
astronomers took a page from the book of the late skywatcher
Clyde Tombaugh--who discovered Pluto in 1930--and switched
between different images of the same area, taken days apart, to hunt for the planet.
But where Tombaugh used photographic plates, New Horizons researchers
relied on digital images taken of Pluto's expected location by their probe's
Long Range Reconnaissance Imager (LORRI). The small planet was easily
identified as it moved against the background of stars.
"We
won't get useful science out of these first detections of Pluto," Stern
said. "But during the next several years of approach, we'll use LORRI to
study Pluto's brightness variation with our angle to the Sun to build a 'phase
curve' we could never get from Earth or Earth orbit."
That
should yield new details of Pluto's frigid surface well before New Horizons
makes its flyby past the dwarf planet on July 14, 2015, he added.
In
the meantime, New Horizons researchers are content to know that the probe's
long-distance camera is working well, and eagerly awaiting next year's Feb.
28slingshot past Jupiter. The
spacecraft was built for NASA by Johns Hopkins Applied Physics Laboratory,
which is also managing the mission's more than nine-year flight.
Travelogue to Pluto
Since
its Jan.19
launch, New Horizons has snapped photos of the asteroid JF56--during a June
13 pass--as well as the star
Messier 7 and the gas
giant Jupiter on its way to Pluto.
The
Pluto portrait was taken between Sept. 21-24, stored
aboard New Horizons and only recently relayed back home to Earth. New Horizons
was about 2.6 billion miles (4.2 billion kilometers) from its planetary target
at the time of the LORRI image.
"Those
of us who calibrated LORRI on the ground and in flight are not surprised to see
what it can do, but we are mighty grateful that LORRI has survived launch and
its first several months in space without any loss of performance," said LORRI
principal investigator Andy Cheng, of the Applied Physics Laboratory, in a
statement.
NASA
has billed New Horizons' journey as the U.S. space agency's fastest mission to
date despite its long travel time. Stern and his fellow mission scientists are
hoping to send their spacecraft past Pluto to visit at least one other icy
object in the distant Kuiper Belt, which stretches beyond the orbit of Neptune. [Click here
for a graphic of the probe's flight path.]
New Horizons
is currently speeding through the solar system at about 20.8 kilometers per
second with respect to the Sun. That's about 46,528 miles per hour (74,880
kilometers per hour).
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