Helios (French reconnaissance satellites)

Helios 1A

Helios 1A.

Helios are advanced French optical military reconnaissance satellites based on SPOT 4. The Missile and Space Directorate (DME) of the French armament agency (DGA) heads the overall Helios program, which is funded by France, Spain, and Italy. The imaging system uses 4,096 × 2,048 pixel linear CCDs (charge-coupled devices) to provide images with 1–5 meter resolution. Helios-1B suffered a breakdown of its power supply system and could no longer function after operating for just under its 5-year nominal life expectancy.


The Helios space probes completed their primary missions by the early 1980s but continued to send data up to 1985. They are no longer functional yet remain in their elliptical orbits around the Sun.


spacecraft launch vehicle launch date launch site orbit mass (kg)
Helios 1A Ariane 4 Jul 7, 1995 Kourou 679 × 682 km × 98.1° 2,537
Helios 1B Ariane 4 Dec 3, 1999 Kourou 679 × 681 km × 98.1° 2,537