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SPOT 3 Overview

Mission Background

SPOT is a commercial high-resolution optical imaging Earth observation satellite system operating from space. It is run by Spot Image, based in Toulouse, France. It was initiated by CNES, the French space agency, in the 1970s and was developed in association with Belgium and Sweden. It has been designed to improve the knowledge and management of Earth by exploring the planet's resources, detecting and forecasting phenomena involving climatology and oceanography, and monitoring human activities and natural phenomena. 

Satellite Design

The spacecraft was three-axis stabilised to 0.1 deg using momentum wheels. A single solar array generated 1,000 W of power. Downlink at 8 GHz and 2 x 25 Mbps. A hydrazine propulsion system provided orbit maintenance.

CNES innovated over Landsat was in equipping the SPOT satellites with steerable mirrors to enable viewing on either side of the ground track, over a 950 km swath, and to acquire imagery from different angles for relief mapping, notably to generate digital terrain models.

Technical Specification
Mass1869 kg
Dimensions3.5 m x 15.6 m
Design Lifetime4 years

Mission Operations

The SPOT orbit is polar, circular, Sun-synchronous, and phased. The inclination of the orbital plane combined with the rotation of Earth around the polar axis allows the satellite to fly over any point on Earth within 26 days. The orbit has an altitude of 832 kilometres, an inclination of 98.7°, and completing over 14 revolutions per day.

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