The Leapfroggers by V.P. Sandlas

Author:V.P. Sandlas
Language: eng
Format: epub
Tags: null
Publisher: HarperCollins Publishers India
Published: 2018-03-09T16:00:00+00:00

8

SLV-3-E-01: THE PARTIALLY UNSUCCESSFUL FLIGHT

After the conclusion of SLV-3 subsystem testing and qualification programme using Centaure rockets, the SLV-RH-560-01 Controlled Flight on 15 October 1977 and the December 1977 decision of the SLV-3 PMB to drop S2+S4, full thrust activities started at all work centres to realize the SLV-3-E-01 flight at the earliest. It was almost a more complex system by an order of magnitude than the configuration of the earlier RH-560 Controlled Flight: the four rocket motors, two inter-stage assemblies on both sides of each motor, heat shield and the payload constituted 14 sub-assemblies of SLV-3. Qualification-testing of subsystems and sub-assemblies, prototype integration and functional evaluation were the primary tasks during 1978. The overall configuration consisted of 150 functional electrical and electronic units, 135 signal/data amplifiers, 45 power regulators and 40 battery packs. For interconnecting and interfacing these units with Pyro Systems, Safe/Arm circuits, Control Actuators, Power Control & Distribution, Checkout System, Pressure Pickups, Temperature/Strain Sensors, Transient Suppression Circuits, Battery Charging, etc., and to systematize the Integration and Checkout operations for consistent and repeatable performance, 95 independent Interface Units were designed and developed. The entire system was interconnected through 1,300 connectors, and further interfaced to the Ground Checkout System through about 1,000 Umbilical Lines.

It had earlier been decided that the first flight of SLV-3 would carry the Rohini Technology Payload (RTP), primarily for the in-flight measurements of the performance of the fourth stage. The RTP was designed to carry battery for providing power up to about 90 minutes after separation from the fourth stage, and two solar panels for additional and supplementary coverage for in-orbit monitoring. The experimental solar cells were supplied by M.K. Gupta’s group at BARC (coincidentally, M.K. Gupta was from the first batch of BARC training school—a batchmate of Easwara Das and Kurup). Since many subsystems of RTP were identical with RS-1 satellite, under development at ISAC, there were many priority and schedule-related problems.

Once, Kalam got so perturbed after meeting U.R. Rao that he called me from Bangalore to rush to ISAC the very next day, and asked me to immediately send a telex to U.R. Rao—in his own name—with suggested decision options. This kind of action was typical of Kalam—not giving up, and down delegation of the highest kind; he was known for unusual belief and trust in some of his subordinates—this was one of his ways of extracting maximum work out of them, and providing them exposure via involvement at higher levels. Of course, we had no problem discussing and managing at working level at ISAC, particularly with Tarsem Singh, Project Manager RS-1, who was also a classmate of Kalam from their MIT days.

We did have some technical problems because of 10W Power Amplifier at 136MHz in RTP, since it was interfering with the Tone Range Receiver in the Payload Interface and also with Telecommand Receiver in the Equipment Bay, which were solved by retrofit techniques such as additional filtering and shielding. Another area of concern was the tracking of RTP (also for RS-1) after becoming non-visible from the ISRO Telemetry, Tracking and Command Network (ISTRAC) at SHAR.

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