Composante Spatiale Optique
French military Earth observation satellite program
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Composante Spatiale Optique (CSO; English: Optical Space Component) is a French military Reconnaissance satellite program of third generation. It replaces the Helios 2 satellites. It is sometimes referred to as the MUltinational Space-based Imaging System for Surveillance, Reconnaissance and Observation (MUSIS program).
CSO-2
CSO-3
| |
| Names | CSO-1 CSO-2 CSO-3 |
|---|---|
| Mission type | Military reconnaissance |
| Operator | CNES / DGA |
| COSPAR ID | 2018-106A (CSO-1) 2020-104A (CSO-2) 2025-044A (CSO-3) |
| SATCAT no. | 43866 (CSO-1) 47305 (CSO-2) 63156 (CSO-3) |
| Mission duration | 10 years (planned) |
| Spacecraft properties | |
| Bus | CSO |
| Manufacturer | Airbus Defence and Space (satellite) Thales Alenia Space (optical payload) |
| Launch mass | 3,655 kg (8,058 lb) (CSO-1) 3,652 kg (8,051 lb) (CSO-2) |
| Start of mission | |
| Launch date | 19 December 2018, 13:37:00 UTC (CSO-1) 29 December 2020, 16:42:07 UTC (CSO-2) 6 March 2025, 16:24:26 UTC (CSO-3) |
| Rocket | Soyuz ST-A (CSO-1, CSO-2) Ariane 62 (CSO-3) |
| Launch site | Guiana Space Centre, ELS (CSO-1, CSO-2) Guiana Space Centre, ELA-4 (CSO-3) |
| Contractor | Progress Rocket Space Centre, Arianespace |
| Orbital parameters | |
| Reference system | Geocentric orbit |
| Regime | Sun-synchronous orbit |
| Altitude | 800 km (500 mi) (CSO-1) 480 km (300 mi) (CSO-2) 800 km (500 mi) (CSO-3) |
| Inclination | 98.6° (CSO-1/CSO-3) 97.3° (CSO-2) |
Program history
Since the launch of Helios 1A in 1995, France has developed a series of military Earth observation programs. Due to the limited lifetime of satellites, a program was launched to replace the currently operational Helios 2 satellites. This program started as a French contribution to the larger pan-European MUSIS program, and eventually became a mostly French program.[1] An agreement between France and Germany was reached in April 2015, under which Germany contributes €200 million to building a third satellite, and in exchange receives access rights to the imagery.[2][3] Sweden and Belgium are also a program partners, which enables the use of a polar ground station.[4][5]
Technical capabilities
Unlike the Helios satellites, which used the same bus as the Spot satellites, CSO uses technology derived from the Pléiades satellites. It is much heavier than Pléiades with a mass of 3650 kg.[6] They are made out of 3 identical satellites. The first one was launched in December 2018, and provide Very High Resolution imagery - like the Helios 2 satellites,[7] so around 35 cm [8] from an 800 km orbit.[9] The second satellite provides Extremely High Resolution imagery - around 20 cm - from a 480 km orbit.[6] The third satellite was launched in March 2025 and provides increased revisit capabilities.[10][11] The satellites have the ability to take infrared images.[12] The satellite manufacturing was awarded to Airbus Defence and Space, while the optical payload is built by Thales Alenia Space.[13]
The CSO system is able to produce at least 280 images a day on average.[4][14]
The program cost is estimated at €1.3 billion,[1] with an additional €300 million for the ground segment and 10 years of operations.[15] The marginal cost of the third satellite is €300 million.[2]
