will also require daily access to the stored data 
that is downlinked to the EOSAT ground- 
processing facility within 24 hours of their acquisi- 
tion. 
Researchers will use the data downlinked to 
the EOSAT ground-processing facility after it is 
transferred to the NASA/GSFC facility. Occasion- 
ally, quick-look data products for selected areas 
will be required within 12 hours of collection for 
positioning research vessels. However, for the 
most part, research needs will be satisfied if the 
raw data are available within 7 days of acquisition 
and other data products are available within 8 to 
10 days of collection. 
Implementation of 
Requirements 
The purpose of the Implementation Panel was 
to translate the mission objectives of the commer- 
cial, operational, and research users into a work- 
able system concept that would provide the data 
required to meet the users’ needs. The work of 
TILT MECHANISM 
VNIR AFT ASSEMBLY 
DICHROIC BEAMSPLITTERS 
TIR AFT ASSEMBLY 
\ 
RADIATIVE 
COOLER 
SUMMARY 
this panel supported the other panels by defining 
the technical tradeoffs among the performance 
parameters and by identifying the practical conse- 
quences of various options in terms of cost and 
complexity. Thus, the Implementation Panel esta- 
blished a feasibility envelope for the Working 
Group, leading to a system concept that was not 
only useful from the users' perspective, but also 
technically and economically realizable. 
Sensor Design Concept 
The baseline SeaWiFS design, meeting all de- 
sired sensor requirements, is shown in Figure A-1. 
The sensor concept is based on low-cost, low- 
risk technology and results in a lightweight and 
compact instrument. In the proposed design, the 
telescope rotates 360° about a pivot axis to scan 
the scene, thereby avoiding the use of a scan mir- 
ror and its associated polarization effects. Specu- 
lar sun reflection is avoided by tilting the telescope 
in the plane perpendicular to the scan plane (i.e., 
along track) to one of three positions: +20°, 0°, 
Figure A-1. 
Baseline Sea- 
WiFS design. 
HALF-ANGLE MIRROR 
SOLAR DIFFUSER 
TRACK (TILT) 
