Baseline SeaWiFS Design 
In the proposed baseline SeaWiFS design 
concept, shown in Figure 21, the telescope ro- 
tates 360° about a pivot axis to scan the scene, 
thereby avoiding the use of a scan mirror and its 
associated polarization effects. Also, the fold mir- 
rors used to direct the scene energy out of the 
IMPLEMENTATION PANEL 
telescope are located so as to minimize angles of 
incidence, and the half-angle mirror is placed in 
the plane perpendicular to the fold mirrors. This 
allows the polarization introduced by the half- 
angle mirror to be partially balanced by the fold 
mirrors’ contributions. The resulting polarization 
sensitivity is less than 1.4%, well within the Sea- 
WIFS requirement of 2%. 
Figure 21. Baseline 
SeaWiFS design. 
TILT MECHANISM 
VNIR AFT ASSEMBLY 
DICHROIC BEAMSPLITTERS AG Als< 
TIR AFT ASSEMBLY 
COOLER 
fh, 
BSN 
SCAN MECHANISM 
SCAN 
AXIS 
HALF-ANGLE MIRROR 
SOLAR DIFFUSER 
=x /j}\ TRACK (TIL 
RADIATIVE oN Ee mED 
51 
NADIR 
