The Ariane Passenger Payload Experiment (APPLE) was ISRO’s first indigenous, exploratory correspondence satellite. It was propelled into GTO (Geosynchronous Transfer Orbit) by the third improvement trip of ESA’s Ariane vehicle from Kourou on June 19, 1981. It was helped into Geosynchronous Orbit (GEO) by apogee engine of ISRO, got from fourth stage engine of SLV-3. It was outlined and worked in only two years with the constrained framework in mechanical sheds. It gave ISRO significant hands-on involvement in planning and creating three-pivot balanced out geostationary correspondence satellites and in addition in circle raising moves, in circle arrangement of extremities, station keeping, etc. APPLE was utilized for almost two years to complete broad analyses on time, recurrence and code division different access frameworks, radio systems administration PC interconnect, irregular access and pockets exchanging tests.
On July 16, 1981, the satellite was situated at 102° E longitude. The 672 kg satellite filled in as the test bed of the Indian broadcast communications space transfer framework notwithstanding the disappointment of one sun-powered board to send. It was utilized as a part of a few correspondence tests including the transfer of TV projects and radio systems administration. It was a tube-shaped rocket estimating 1.2 m in breadth and 1.2 m high.
