SPOT was the French government-sponsored civil earth observation program. A single SPOT satellite provides complete coverage of the Earth every 26 days. Image products from SPOT were sold by a commercial entity, SPOT-Image Corp.

The SPOT-4 spacecraft was 3-axis stabilized, and used a single 5-panel solar array, each panel being 2.6 x 1.9 m. A hydrazine propulsion system provided orbit maintenance.

Two HRVIR (High Resolution Visible - Infrared) push-broom imaging instruments were carried. HRVIR was derived from the HRV instruments on SPOT 1-3. This system provided 10 m resolution in the panchromatic band and 20 m resolution in the multispectral bands. HRVIR included a new medium IR channel to support vegetation analysis and harvest forecasting. The HRVIRs were steerable to within 27 deg off-nadir. Each HRVIR had a swath width of 60 km. The Vegetation Monitoring instrument had 1 km resolution in the same bands as the HRVIR. SPOT-4 also carried the PASTEL optical link terminal supported laser crosslink experiments and DORIS (Doppler Orbitography and Radiopositioning Integrated by Satellite) precision orbit determination system. The $ 110 million Silex - semiconductor laser intersatellite link experiment. provided data relay for Artemis.

Design Life: 5 years. Typical orbit: 832 km, sun-synchronous, repeating every 26 days. Length: 5.40 m (17.70 ft). Maximum Diameter: 2.00 m (6.50 ft). Mass: 2,755 kg (6,073 lb). Associated Launch Vehicle: Ariane 4.

• 1998 March 24 - SPOT 4 - Program: SPOT. Launch Site: Kourou. Launch Vehicle: Ariane 4. Mass: 2,755 kg (6,073 lb). Perigee: 824 km (512 mi). Apogee: 826 km (513 mi). Inclination: 98.70 deg. Period: 101.40 min.

  Developed by Matra Marconi Space/Toulouse for CNES, the satellite provided 10-m resolution images with a wide field of view. SPOT 4 also carried a wide field 'vegetation' imager and a laser communications experiment. Launch was by an Arianespace Ariane 40 rocket, the base Ariane 4 model with no strap-on boosters. The liquid hydrogen fuelled third stage of the Ariane 40 entered an 800 km sun-synchronous orbit together with SPOT 4.

• JPL Mission and Spacecraft Library, Jet Propulsion Laboratory, 1997. Accessed at: http://msl.jpl.nasa.gov/home.html.