Composante Spatiale Optique


Composante Spatiale Optique is a French military Earth observation satellite program. It will replace the Helios 2 satellites. It is sometimes referred to as the MUSIS program.

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. An agreement between France and Germany was reached in April 2015, under which Germany contributes 200M€ to building a third satellite, and in exchange receives access rights to the imagery. Sweden is also a program partner, which enables the use of a polar ground station.

Technical capabilities

Unlike the Helios satellites, which used the same bus as the Spot satellites, CSO will use technology derived from the Pleiades agile satellites. It will be much heavier than Pléades with a mass of 3.5t. They will be made out of 3 identical satellites. The first one will be launched in 2018, and will provide Very High Resolution imagery -like the Helios 2 satellites, so around 35 cm- from an 800 km orbit. The second one will provide Extremely High Resolution imagery -around 20 cm- from a 480 km orbit. The third one will be launched in 2021 and will provide increased revisit capabilities. The satellites will have the ability to take infrared images. The satellite manufacturing was awarded to Airbus Defence and Space, while the optical payload will be built by Thales Alenia Space.
The CSO system will be able to produce at least 280 images a day on average.
The program cost is estimated at 1.3 billion Euros. with an additional 300 million for the ground segment and 12 years of operations. The marginal cost of the third satellite is 300M€.