KOZ is the Imager and
Sounder Keep Out Zone,
it occurs at certain times of the day (centered around Spacecraft midnight) when the
instruments would be looking at the Sun when Scanning. The KOZ starts
about 10 days before each eclipse season and end about 10 after
the last eclipse. Major concern is rapid heating of the
instrument mirrors which could compromise the instruments and the
mission.
Single Chord is in reference
to our Earth Sensor operations, which normally use two scans, one in the North
and on in the South, for attitude control. Whenever the Moon or the Sun is
about to enter the scan area, NOAA inhibits that scan so that the offending
object does not corrupt our attitude control.