The Multi-angle Imaging SpectroRadiometer (MISR) was launched into polar
orbit aboard NASA's Terra spacecraft on December 18, 1999. Testing began
even before the instrument cover opened. The 1000-line image at left, corresponding
to about 41 seconds of "dark current" data, was acquired on February
12, 2000, during orbit 821. The image at right shows the same data, but
with the contrast greatly enhanced. Random fluctuations in the camera video
signal produce the "salt and pepper" appearance, and the faint
horizontal banding is due to random fluctuations in the video background
level. The brightness of all these fluctuations is less than 0.3% above
the average background level with the camera cover closed, a minuscule amount
compared to the signal produced when Earth light illuminates the cameras.
