HAMSAT – Small Satellite Operations, A Case Study
- Paper number
IAC-07-B4.3.01
- Author
Mr. T. Parimalarangan, Indian Space Research Organisation (ISRO), India
- Coauthor
Mr. F.B. Singh, Indian Space Research Organisation (ISRO), India
- Coauthor
Mr. P. Soma, Indian Space Research Organisation (ISRO), India
- Coauthor
Mr. S.K. Shivakumar, Indian Space Research Organisation (ISRO), India
- Year
2007
- Abstract
HAMSAT is a micro-satellite, launched as an auxiliary payload onboard PSLV-C6 on 5 May 2005, with an objective of developing and operating a micro-satellite, flying a payload for the benefit of amateur community and testing of various new elements / technologies such as onboard autonomy for attitude and spin control through a miniature Bus Management Unit, high efficiency GaAs solar cells, Li-Ion battery, miniature magnetometers, indigenous RF components etc. Thus, all the new elements / technologies have provided the much-required input from the space environment and endowed with confidence for the high-tech, future operational micro satellites of ISRO. The satellite was designed to be a passive spinner, with no redundancy onboard, but for the payload transponder. The TTC operation is in VHF, while the payload is operating in UHF&VHF for uplink and downlink, respectively. Thus the mission needs to be supported in VHF-TTC for the purpose of telemetry, telecommand and tracking.
To match the onboard autonomy, ISTRAC has installed an automated, low-cost and state-of-the-art VHF ground system that continues to provide elegant support. It was a well thought out initiative to adopt the commercial products, yet qualifying for space operations. The established VHF-TTC system is capable of receiving HAMSAT telemetry for monitoring the health of the satellite, uplinking tele-commands for change of onboard configuration and extracting one-way doppler data for the purpose of orbit determination. The VHF-TTC System is configured to consist of independent antenna for transmit and receive, with associated COTS drive systems. The antenna is driven by a personal computer, where the software resides for generating predicts with the necessary interface for drive units. The tracking is generally planned for programme mode of tracking, with provision for manual operation. The received signal is amplified through low noise amplifiers and down converted, before fed in to TTC processor, which does multiple functions such as demodulation, diversity combining, bit and frame synchronization and doppler extraction. The formatted and time tagged telemetry data is put on display for monitoring purpose through the station computer. On the uplink side, the tele-command is AM modulated and power amplified by a solid-state power amplifier before despatching it through transmit antenna. All this happens in an automated mode, without anybody attending to the system.
The major challenge was to integrate various modules that will serve the mission specifications and the mission it self. This design has set the tone for low-cost ground systems for micro satellites of ISRO. Thus a new era has dawned in TTC operations of ISTRAC/ISRO, wherein, the tracking is carried out and TM downlinked in autonomous mode, liberating the valuable technical manpower. The normal phase operations continued to be carried out through this automated ground system, with uninterrupted services to the user community. * tprangan@istrac.gov.in, Ph:080-28094207/080-28094583(O),080-25350132(R)
- Abstract document
- Manuscript document
IAC-07-B4.3.01.pdf (🔒 authorized access only).
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