SPOT-4

SPOT (Satellite Probatoire d'Observation de la Terre) is the French government sponsored civil Earth observation program, with support from Belgium and Sweden. A single SPOT satellite provides complete coverage of the Earth every 26 days. Image products from SPOT are handled by a commercial entity, SPOT-Image Corp.

Spacecraft
3-Axis stabilized. Single 5-panel solar array, each panel is 2.6 x 1.9 m. Hydrazine propulsion system provides orbit maintenance.

Payload
Two HRVIR (High Resolution Visible - Infrared) pushbrrom imaging instruments are carried. HRVIR is derived from the HRV instruments on SPOT 1-3. This system will provide 10 m resolution in the panchromatic band and 20 m resolution in the multispectral bands. HRVIR includes a new medium IR channel to support vegetation analysis and harvest forecasting. The HRVIRs are steerable to within 27 deg off-nadir. Each HRVIR has a swath width of 60 km. The Vegetation Monitoring instrument has 1 km resolution in the same bands as the HRVIR. PASTEL optical link terminal supports laser crosslink experiments. DORIS (Doppler Orbitography and Radiopositioning Integrated by Satellite) precision orbit determination system.

Country of Origin	France
Customer/User	CNES, SPOT-Image Corp.
Manufacturer(s)	Matra Marconi
Size	2 m x 2 m x 5.4 m
Launch	Planned for launch in 1997
Orbit	832 km, sun-synchronous, repeating every 26 days (14 5/26 revs per day), 98.7 deg inclination
Design Life	5 years