Friday, March 29, 2013

India's remote sensing programme makes new advances... an article of mine on India's plans to develop a Geo Imaging Satellite....

Here's a short essay of mine on the Indian plans to develop a Geo Imaging satellite called, GISAT. A statement to that effect was made in the Parliament last week....

If India were able to sustain the launches of remote sensing satellites as per the plans, it would significantly beef up its ability to deliver services, products and other inputs in the field of climate, cartography and agriculture.



In a statement in the Parliament last week, the Indian government said that the Indian Space Research Organisation (ISRO) will be developing a Geo Imaging Satellite called GISAT, to be launched sometime in 2016-17. The satellite which is being built at the Space Applications Centre, Ahmedabad, is expected to carry a Geo Imager that will have a constant visual of the same region, and is synchronized to the Earth’s rotation. The Imager with multi-spectral (visible, near infra-red and thermal), and multi-resolution (50m to 1.5 km) imaging instruments, will be one of the best of its kind, able to provide sector-wise pictures every 5 minutes of a particular sector and the entire Indian landmass every 30 minutes at 50m spatial resolution. The satellite, weighing less than 1000 kg will be launched by a Polar Satellite Launch Vehicle (PSLV). This project is being undertaken at a cost of INR 392 crores (around $ 72 million). According to the ISRO Chairman, Dr. Radhakrishnan, the main purpose of this satellite, which will orbit at a height of 36,000 km, is to "observe earth from geo-stationery orbit, enabling continuous observation of Indian sub-continent, to facilitate quick monitoring of natural hazards and disaster."

India’s previous remote sensing satellites have undertaken similar missions, but they have not been geostationary satellites. Orbiting at much lower altitudes, their survey over a particular area is limited to barely ten minutes and they visit the same area only once every several hours or even days. Hence, GISAT, situated permanently in a geo-stationary orbit, is a qualitatively superior one, ensuring for India near real-time imagery for monitoring and responding to natural calamities and tracking other developments in the neighbourhood.

India has been making progress in this area in the last few years. India’s Israel-built RISAT-2, weighing 300 kg and placed at 550 km, uses an X-band synthetic aperture radar from Israel Aerospace Industries (IAI) and was tested in April 2009. The collaboration with Israel came about after Israel’s Tecsar surveillance satellite was launched by ISRO in January 2008. The particular significance of this satellite is its ability to take images under all weather conditions as well as day and night that would enable India to have a constant eye on activities and developments on India’s border areas. While this satellite has huge applications in the area of flood, agriculture, cyclone and disaster management, RISAT-2 is primarily developed for surveillance and defence purposes, including tracking of hostile ships at sea.

In addition, India tested RISAT-1 in April 2012. Though the RISAT-1 programme began earlier, the RISAT-2 was produced and launched first. The RISAT-1 is similar to the RISAT-2 though it appears more for civilian purposes. ISRO had been working on this microwave remote sensing satellite for about 10 years. It uses a C-band Synthetic Aperture Radar. Developed at a cost of Rs. 500 crores, it provides 1-meter resolution surveillance for various civilian purposes including agricultural and weather. Given the large tonnage of the satellite, it was launched using the PSLV-XL rocket, the third time the extra large rocket was used (in October 2008 for India’s Chandrayaan’s mission and in July 2011 for the launch of GSAT-12 satellite).

India has had other similar satellites such as the CARTOSAT series in operation for a while. However, they were able to get only black and white images in visible regions of electromagnetic spectrum. The larger reach of the satellite and the ability to take images under all conditions, day and night and at frequent intervals is a significant advantage.

India’s remote sensing satellites has been at the core of India’s space programme, starting with the launch of IRS-1A in 1988. Thereafter, India has developed a series and currently has 10 operational satellites in orbit including Resourcesat-2, Cartosat-2B, Oceansat-2, Risat-2, Cartosat-2A, IMS-1, Cartosat-2, Cartosat-1, Resourcesat-1.

Megha-Tropiques is an India-French collaboration in order to study the water cycle and energy exchanges in the tropics, essentially to learn about the life cycle of convective systems that influence the tropical weather and climate and their role in associated energy and moisture budget of the atmosphere in tropical regions. Megha-Trpiques is considered exceptional, able to provide scientific data for climate research that could enable better prediction models. This launch is estimated to have four payloads: Microwave Analysis and Detection of Rain and Atmospheric Structures (MADRAS), Sounder for Probing Vertical Profiles of Humidity (SAPHIR), Scanner for Radiation Budget (ScaRaB), Radio Occultation Sensor for Vertical Profiling of Temperature and Humidity (ROSA). India has plans for additional launches in the remote sensing arena, with potential launches including CARTOSAT-3, INSAT-3D.

If India were able to sustain the launches as per these plans, it would significantly beef up its ability to deliver services, products and other inputs in the field of climate, cartography and agriculture. It would have other benefits also, especially in space cooperation because many of these are collaborative efforts. Such abilities could spur greater regional and global cooperation that is beneficial in many ways - strengthen India’s own R&D in this area while making these programmes cost-effective for different players as well as contribute to the long-term sustainability of outer space. Collaboration of this nature will go a long way in building the much-needed trust between space actors that could potentially lead to developing rule-based space governance architecture.

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