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