Pléiades (satellite)
The Pléiades constellation is composed of two very-high-resolution optical Earth-imaging satellites. Pléiades-1A and Pléiades-1B provide the coverage of Earth's surface with a repeat cycle of 26 days. Designed as a dual civil/military system, Pléiades will meet the space imagery requirements of European defence as well as civil and commercial needs. History. The Pléiades system was designed under the French-Italian ORFEO Programme (Optical and Radar Federated Earth Observation) between 2001 and 2003. The Pléiades programme was launched in October 2003 with CNES (the French space agency) as the overall system prime contractor and  EADS Astrium as the prime contractor for the space segment. Spot Image is the official and exclusive worldwide distributor of Pléiades products and services under a delegated public service agreement. Technologies. Orbit. The two satellites operate in the same phased orbit and are offset at 180° to offer a daily revisit capability over any point on the globe. The Pléiades also share the same orbital plane as the SPOT 6 and 7, forming a larger constellation with 4 satellites, 90° apart from one another. Equipment. Equipped with technologies like fibre-optic gyroscopes and control moment gyroscopes, Pléiades-HR  1A, and 1B offer roll, pitch, and yaw (slew) agility, enabling the system to maximize the number of acquisitions above a given area. Agility for Responsive Tasking. This agility coupled with particularly dynamic image acquisition programming make the Pléiades system very responsive to specific user requirements. Individual user requests was answered in record time, thanks to multiple programming plans per day and a state-of-the-art image processing chain. Performance at a glance: Ground receiving stations. When satellite operations begin, four ground receiving stations will be deployed for the direct downlink and archiving of imagery data: Regional receiving stations  (fixed or mobile) are subsequently installed at the request of users. Uplink Stations. The Pléiades tasking plan are refreshed and uploaded three times per day, allowing for last minute requests and the ability to utilize up-to-the-minute weather forecasts. Applications of VHR imagery. The Pléiades system is designed for a range of very-high-resolution (VHR, panchromatic: 50 cm), remote sensing applications. These include: