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Europe's Venus Express Probe Looks Back at Earth

Europe's Venus Express Probe Looks Back at Earth
Venus Express took this thermal view of Earth during an infrared observation with its VIRTIS instrument. The planet appears almost 'fully illuminated' with no difference from day and night regions since only the thermal radiance is seen. The Antarctica region, being colder, generates a weaker signal.
(Image: © ESA/VIRTIS Team.)

A Europeanprobe bound for Venus has taken a parting glance at its home world as it headstoward its cloudy quarry.

TheEuropean Space Agency's (ESA) Venus Express probe photographed Earth and the Moonin both visible and infrared light during a shakedown of its instrumentpackage, which includes the VIRTIS imaging spectrometer.

"It showsthat the instrument is really working beautifully," Kevin Baines, a NASAparticipating scientist with Venus Express' VIRTIS team, told"It bodes well for the rest of the mission."

VIRTIS, an instrumentthat scans objects in the ultraviolet, visible and near-infrared range of thelight spectrum, is designed to track Venus' thick clouds at varying altitudes,as well as study their composition. Like many of the instruments aboard VenusExpress, VIRTIS is similar to a tool flown on a previous ESA mission - in thiscase the comet-bound Rosettaprobe.

When pointedat Earth, VIRTIS returned a familiar globe of blue and white - with day andnight sides easily discernable - in the visible range, while an infrared viewpresented a thermal glimpse of a planet awash in warm reds. The observationswill serve as a benchmark for comparison once the spacecraft reaches Venus, ESAresearchers said.

"Acomparison of Venus spectra with Earth spectra with the same instrument willalso be of interest for textbook illustration of the comparison between the twoplanets," said Pierre Drossart, one of two principal investigators for theVIRTIS instrument, in a statement.

VenusExpress turned its VIRTIS eye on the Earth-Moon system from a distance of about2.1 million miles (3.5 million kilometers).

The probe'ssix other primary instruments, such as its Venus Monitoring Camera, are alsogoing through their own series of checks and evaluations.

"It's liketesting a new airplane or car," Baines said. "Before you go off joyriding withit, you want to make sure everything works."

VenusExpress launchedspaceward late Nov. 8 EST from Kazakhstan's Baikonur Cosmodrome and is expectedto reach Venus in April 2006.

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