Origin of DMSP 1.9-second flashes, part 2

Ed Cannon (ecannon@mail.utexas.edu)
Sat, 06 Sep 1997 15:28:32 -0500

Pardon me for sending two messages on this, but I just found this, and it
has more detail:


> 3. Instrument Layout, Design, and Measurement Geometry:
>     List of Sensors:
>          Passive Microwave Radiometer 
>     Sensor Descriptions:
> The SSM/I rotates continuously about an axis parallel to the local spacecraft 
> vertical at 31.6 rpm ....  The scan direction is from the left to the right 
> when looking in the forward (F10,F11) or aft(F8) direction of the spacecraft 
> with the active scene measurements lying 151.2 deg about the forward
> or aft (F8) direction. This results in a swath width of approximately 1400
> The spin rate provides a period of 1.9 sec during which the spacecraft sub-
> satellite point travels 12.5 km. 

Slight discrepancy -- this says 31.6 rpm (1.8987 sec/rotation), while the other 
document said 31.9 (1.8807 sec).  I presume that one of them is a typo.

Ed Cannon
Austin, Texas, USA
30.3086N, 97.7279W, 165m