From an orbit 828 kilometers high, a satellite equipped with two high-resolution camera telescopes captures vivid views that yield important data about the Earth's diverse landscape.

Pictures taken by France's SPOT satellite system are as scientifically valuable as they are aesthetically pleasing. Since commencing operation in May 1986, the satellite and a network of image receiving and processing stations located in 11 countries have provided images of Earth to geologists, cartographers, forest managers, agronomists, land-use planners, environmental researchers, and engineers from all disciplines.

The SPOT system was designed by CNES (France's Center for Space Studies) and produced under the supervision of Matra S.A. Paris). in January 1990, the advanced SPOT 2 satellite was sent into helio-synchronous orbit by Arianespace to assume picture-taking duties from SPOT 1. SPOT 2 images are taken in three bands at different wavelengths (green, red, near infrared) that yield information about soil or vegetation.

The ability of SPOT 2 to shoot images several times per month means that studies of any region can be conducted on a regular basis. Aloft at an altitude of 828 kilometers 515 miles), SPOT 2 requires 26 days to complete coverage of the entire Earth. In the course of this journey, SPOT 2 is able to observe ever point on the Earth's surface b optical imaging instruments have a 117-kilometer (73-mile) field of view.

The heart of the SPOT system is two high-resolution camera telescopes equipped with charge-coupled devices (CCD) that provide high-resolution imaging. Each telescope measures 2.5 meters (8.2 feet) in length and weighs 250 kilograms (551 pounds). Each CCD detector analyzes 10-meter segments of the landscape below, and each row of 6000 CCDs can analyze 60 kilometers (37.3 miles) of landscape.

Whenever SPOTis in visible contact with one of its 12 ground stations, it transmits imaging data at a rate of 24 million bits per second. Its principal receiving stations are in Toulouse, France, and Kiruna, Sweden. As a result of its low-level orbit, the satellite is in contact with monitoring stations an average of only one hour per day. In this respect, the heliosynchronous SPOT is different from geostationary satellites that are continuously in sight of their monitoring stations. SPOT maintains operations during communications blackout periods via software that manages picture taking and stores imaging data.