Aryabhata

Aryabhata, India’s first satellite, was successfully launched into a near earth orbit on 19 April 1975, from a USSR cosmodrome. The launch of the satellite proved India’s indigenous capability in satellite technology. The satellite also included three scientific experiments. The launch of the satellite not only proved the India’s capability but also created  the expert scientists and engineers who  contributed significantly in launching India’s first mission to Moon, Chandrayaan-I.

Objectives of the Aryabhata Mission,

• Indigenous design and fabrication of a satellite and the evaluation of its performance in orbit
• To have the capability to perform a series of complex operations on the satellite in the orbit
• To have the capability to set-up the necessary ground stations required to communicate with the satellite.
• To test the capability to fabricate, test and qualify the sophisticated spacecraft systems.

Technical Details:

• Total satellite weight – 358 kg
• The capability to maintain the internal temperature between 0 and 40o C.
• Body-mounted silicon solar panels and rechargeable Ni-Cd chemical batteries.
• A PCM/FM/PM down link for communication.
• Total of 91 parameters were monitored
• Real-time data transmission at the rate of 256 bits/sec.
• Non-real time date transmission at the rate of 2560 bits/sec.
• Carrier frequency for the down-link was137.44MHz.
• Carrier frequency for the up link was 148.25MHz.
• Doppler, interferometry and tone ranging systems were used to for the satellite tracking purpose

Scientific experiments:

• X-ray astronomy
  • To investigate celestial x-ray sources primarily in relation to their time variation effect in energy range of 2.5-150 Kev.
• Solar neutrons and gamma rays
  • To detect high energy neutrons and gamma rays from the sun both during quiet times and flares.
• Aeronomy
  • To detect super thermal electrons up to 100ev and to measure the intensities of Lyman alpha and oxygen line at F-region altitudes of the earth’s ionosphere

However, ISRO was forced to switch-off these three experiments due to problems with the power supply.

Some of the experiments successfully conducted were,

• Voice transmission experiment
• Transmission of weather data

A ground station was also set up at Sriharikota near Madras for command and tracking purpose. The satellite was fabricated at HAL, Bangalore. The most of the components used to build the satellite were imported. However, ISRO did gain valuable experience in thermal and power control systems, stabilization and attitude sensor systems, orbiter prediction, telemetry, tracking and telecommand through in-orbit operation and experiment. It was in the orbit till 11 April, 1981.

Source: http://www.indianspacestation.com/space-alphabet/82-aryabhata.html