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Launch Date: 19.06.1981


APPLE was an experimental communication satellite successfully launched by Ariane-1,from Kourou,French Guiana on june 19,1981.The spacecraft bus was cylindrical with a diameter of 1.2mtr and a height of 1.2 mtr.The communication payload consisted of two 6/4GHz transponders connected to a .9mtr diameter parabolic  antenna.APPLE successfully served as a test bed for the entire Indian telecommunications space relay infrastructure despite the failure in deployment of one solar panel. Solid Fuel Apogee Kick Motor was used for orbit raising.

Initial phase of the operation used spin mode and later part was three-axis stabilized. SHAR ground station was used for all the mission activities. Apple was used in several communication experiments including relay of TV programmes, and radio networking. It was used to carry out extensive experiments on time, frequency and code division multiple access systems, radio networking computer inter connect, random access and pockets switching experiments. It also provided an opportunity to introduce state-of-the-art technologies of the day, such as momentum biased three axis stabilization techniques, motor driven deployed solar array, earth sensing for attitude control, C-band transponder design, inclusive of composite reflector, orbit raising, station acquisition, station-keeping and a host of mission management and flight dynamic techniques.


Experimental  communication

Lift-off Mass

670 kg

Spacecraft Power

Solar Array: 210 Watts

Platform System



3-axis stabilized (biased momentum) with momentum wheels, torquers & hydrazine 
based reaction control system sensors: static earth sensor,imported scanning earth
sensor, 4 pi sun sensor, twin slit sun sensor, horizon crossing sensor


2 C band transponders

Launch Date


Launch Site

Kourou (CSG), French Guyana

Launch Vehicle

Ariane-1 (3rd launch) METEOSAT was the co–passenger.


Geosynchronous (102 deg. E  longitude, over Indonesia)


1. First three-axis stabilized experimental geostationary communication satellite.
2. Used in several communication experiments.
3. In–spite of non-deployment of one solar panel, managed the mission for the planned life of two years. Introduced the pitch rotation technique for high temperature zones near eclipse season.

Mission life

Two years


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