Future space
snapshots could reveal the existence of lakes or oceans on Jupiter's moon
Europa, suggesting the possibility of alien life, and astronomers have now
built an imaging detector better up to the task.
Until now,
the imaging
detectors available to take pictures in space have been vulnerable to the
noise and degradation caused by cosmic rays and other radioactive particles.
Environments such as the one surrounding Europa are particularly
radiation-heavy, making observations difficult.
"Radiation
tolerant detectors are a critical need for NASA in the continued
exploration of the solar system," said Melissa McGrath, chief scientist in
the Science and Mission Systems Office at NASA Marshall Space Flight Center.
The
technology driving the new detector is a capturing system that immediately
converts electromagnetic signals into digital information, pixel by pixel. The
method bypasses the standard pathway traveled by analog signals from sensors to
the point where the signal is converted to digital data.
High-energy
radioactive particles in space degrade these circuits, or pathways, over time
and add to noise in the data by making pixels appear artificially bright.
The new
device avoids such pitfalls, said project leader Donald Figer, director of the
Rochester Imaging Detector Laboratory at Rochester Institute of Technology.
"Our
detector converts the analog signal to a digital number within the pixel,"
Figer told LiveScience. "Radiation does not have time to affect the
signal. And once the data is digitized it's essentially impossible to pick up
noise."
The
detector will also be less susceptible to charge traps that can build up in
instruments under exposure to radiation, further degrading the signal.
"The
instrument's benefit will be greatest where the radiation environment is
high," said Figer. The Jovian moons are one such area.
"We
could ... figure out if there are lakes of water on Europa or
hydrocarbons on Titan," Figer said, referring to the much-sought evidence
that life might exist beyond our planet.
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