Composante Spatiale Optique (CSO; English: Optical Space Component) is a French military

Earth observation satellite An Earth observation satellite or Earth remote sensing satellite is a satellite used or designed for Earth observation (EO) from orbit, including spy satellites and similar ones intended for non-military uses such as environmental monitoring, ...

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 The MUltinational Space-based Imaging System for Surveillance, Reconnaissance and Observation (MUSIS) is an international program including France, Italy, Belgium, Germany, Greece, and Spain, aimed at allowing the six nations to share imagery ...

program).

Program history

Since the launch of Helios 1A in 1995,

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...

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.
French Finance Law for 2013 : Defence : Equipment An agreement between France and

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwee ...

was reached in April 2015, under which Germany contributes

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200 million to building a third satellite, and in exchange receives access rights to the imagery.

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and

Belgium Belgium, ; french: Belgique ; german: Belgien officially the Kingdom of Belgium, is a country in Northwestern Europe. The country is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeast, France to ...

are also a program partners, which enables the use of a polar ground station.

Technical capabilities

Unlike the Helios satellites, which used the same

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as the

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satellites, CSO uses technology derived from the Pléiades satellites. It is much heavier than Pléiades with a mass of 3650 kg. 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, so around 35 cm from an 800 km orbit. The second satellite provides Extremely High Resolution imagery - around 20 cm - from a 480 km orbit. The third satellite will be launched in 2023 and provide increased revisit capabilities. The satellites have the ability to take infrared images. The satellite manufacturing was awarded to

Airbus Defence and Space Airbus Defence and Space is the division of Airbus SE responsible for the development and manufacturing of the corporation's defence and space products, while also providing related services. The division was formed in January 2014 during the ...

, while the optical payload is built by

Thales Alenia Space Thales Alenia Space () is a Franco-Italian aerospace manufacturer. A joint venture between the French technology corporation Thales Group (67%) and Italian defense conglomerate Leonardo (33%), the company is the largest satellite manufactur ...

. The CSO system is able to produce at least 280 images a day on average. The program cost is estimated at €1.3 billion, with an additional €300 million for the

ground segment A ground segment consists of all the ground-based elements of a space system used by operators and support personnel, as opposed to the space segment and user segment. The ground segment enables management of a spacecraft, and distribution of pay ...

and 10 years of operations.
Press release from the DGA The marginal cost of the third satellite is €300 million.

References

Sofradir wins military satellite IR detector contract
French Military Planning Law for 2014-2019
Opex360.com article
SpaceNews article
Hearing of the French Space Command Chief by the National Assembly
Article mentioning Pléiades programming rights
Article on Musis on the French Ministry of Defense website
Hearing on the Director of Military Intelligence at the French National Assembly
page on CSO on the CNES website
SpaceNews article on Helios II B {{Orbital launches in 2020 Reconnaissance satellites of France Spacecraft launched in 2018 Spacecraft launched in 2020 2023 in spaceflight 2018 in France 2020 in France 2023 in France Military equipment introduced in the 2010s