An Indian
spacecraft has picked up its first X-rays from the moon with a little help from
a small solar flare.
A European
camera on India's Chandrayaan-1
lunar orbiter detected a faint X-ray signal coming from a region near one
of NASA's old Apollo landing sites for a brief three seconds. But the signal
was clear enough to spot traces of magnesium, aluminum and silicon making up
the lunar region.
"These data
are the building blocks of the first global mineralogical map of the moon - key
to understanding our
only natural satellite," said Detlef Koschny, the European Space Agency's
(ESA) Chandrayaan-1 project scientist.
Chandrayaan-1's
European-built C1XS X-ray camera caught the short X-ray burst from the moon on
Dec. 12 just a small solar flare began pummeling the lunar surface to spark the
fluorescence, ESA researchers said.
Scientists
were surprised to pick up any X-ray signals at all since the flare was about 20
times weaker than the lowest limit the C1XS camera was designed to detect.
"The
quality of the flare signal detected from the moon clearly demonstrates that
C1XS is in excellent condition and has survived the passage of Chandrayaan-1
through the Earth's radiation (or van Allen) belts with very little damage,"
said the camera's principal investigator Manuel Grande of the Aberystwyth
University. "This is excellent news for the rest of the Chandrayaan-1 mission."
Chandrayaan-1
is not the first spacecraft to scour the moon for X-ray signals to uncover secrets of
the lunar surface composition. The space-based Chandra X-ray Observatory and
ESA's SMART-1 moon probe, for example, have also used X-ray cameras to
scrutinize the lunar surface.
But Chandrayaan-1's
camera may yield new insight because of its sensitivity, researchers said.
"The
instrument has exceeded expectations as to its sensitivity and has proven by
its performance that it is the most sensitive X-ray spectrometer of its kind in
history," said Shyama Narendranath, the Chandrayaan-1 instrument operations
scientist at the Indian
Space Research Organisation (ISRO).
India
launched the Chandrayaan-1 toward the moon in October 2008 and entered orbit a
month later armed
with 11 scientific instruments to map the lunar surface and its composition.
The spacecraft also dropped a small probe that slammed into the moon to take
close-up photographs and test technologies for future landers.
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