NASA is
putting the mirrors for its ambitious new James Webb Space Telescope
through
the ultimate cold test — one that exposes them to temperatures hundreds
of
degrees below freezing to make sure they will work in space.
Six of the
space telescope's big beryllium mirrors were
subjected to temperatures as low as minus 415 degrees Fahrenheit (minus
248 Celsius) so engineers could measure in extreme detail how their
shape deformed as they cooled.
The test will allow engineers to
fine-tune the mirrors'
polish so that next time
they are cooled to cryogenic
temperatures extreme cold bends
them into the perfect shape
NASA's
James
Webb Space Telescope is slated to launch in 2014 to begin
scanning the
universe in the infrared range of the light spectrum to peer farther
back into
the universe's history than ever before. The telescope's
mission is expected
to cost about $5 billion.
But first,
its vital mirror system must pass their endurance trials.
The
ultra-cold tests are being performed at the X-ray & Cryogenic
Facility at
NASA's Marshall Space Flight Center in Huntsville, Ala. The building is
the
largest X-ray facility to test big
space telescopes.
These
experiments tell scientists how well each mirror handles changes in
temperature
over a range of environments in space, NASA officials said in a
statement.
The deep
cold required by the space telescope's mirror system is around minus
379
degrees F (minus 228 Celsius), NASA said in a statement. Inside the
operating
telescope, the mirrors must be cooled to extremely low temperatures in
order to
generate a high sensitivity to faint infrared light. Otherwise, distant
galaxies would be lost in the infrared glow created by the mirrors
themselves.
Ultimately,
the James Webb Space Telescope will use a set of 18 connected mirrors
to detect
infrared light from space. The next set of telescope mirrors are
expected to arrive
at the testing site in August.
advertisement
