Innovative Techniques adopted in Extending the Mission Life of IRS-IC Spacecraft beyond a Decade

Paper number

IAC-07-C1.5.01

Author

Mrs. K. Malarmani, ISRO Telemetry, Tracking & Command Network, India

Coauthor

Mr. M. Pitchaimani, ISRO Telemetry, Tracking & Command Network, India

Coauthor

Mr. Soma P, ISRO Telemetry, Tracking & Command Network, India

Coauthor

Mr. S.K. Shivakumar, Indian Space Research Organisation (ISRO), India

Year

2007

Abstract

Indian Remote Sensing satellite, IRS-1C was launched on 28th Dec 1995 by the Russian Molniya rocket into an 820 km circular polar sun synchronous orbit. IRS-1C carried three remote sensing payloads each with different resolution for various applications. IRS-1C, being the first of the 2nd generation satellites of ISRO, had many first-time new features. It carried a hybrid version of control system with hardware and processor based control loops. It incorporated a new drive concept for solar array rotation. But it flew with the older version of Reaction Control System (RCS) designed around bladder based propellant tanks.  
After five years of on-orbit operations, RCS system degraded due to which the long duration inclination correction maneuvers could not be carried out. This resulted in a large local time drift of the orbit leading to gradual reduction in power generation. The power scenario was further aggravated by the intermittent stoppage of both the Sun tracking solar panels. As a result of large change in the local time, sun sighting was made impossible for a Sun sensor, which measured yaw error of the satellite body through Sun observation.
All these constraints posed many challenges to the operations team. Alternative ways to perform inclination maneuvers in order to arrest the rapid change in local time, different modes of solar panel operation to improve power and a fall back option to support yaw loop for 3-axis control were planned and executed. This paper summarizes a few innovative techniques adopted to overcome these constraints resulting in uninterrupted payload services by IRS-1C for over a decade.

Abstract document

IAC-07-C1.5.01.pdf

Manuscript document

IAC-07-C1.5.01.pdf (🔒 authorized access only).

To get the manuscript, please contact IAF Secretariat.