RISAT-2B was placed into an orbit of 555 km with an inclination of 37 degree to the equator.
This is the fourth flight unit of the RISAT programme and it would be used for reconnaissance, strategic surveillance and disaster management.
Key facts:
It has been developed for military and general surveillance purposes. The data will also be used in fields of agriculture, forestry and disaster management support.
With this advanced earth observation satellite, ISRO has introduced a complex new technology. That is a 3.6 metre unfurlable radial rib antenna. This is also going to be the technology of the future.
RISAT-2B is going to RISAT-2, which was placed in the orbit in 2009. RISAT-2 was RISAT-1’s replacement, a microwave remote sensing satellite that was launched in 2012. RISAT-2 was actively used India to monitor activities in camps across the border in Pakistan to thwart infiltration bids by terrorists.
With the successful pre-dawn launch of RISAT-2B satellite on May 22, the Indian Space Research Organisation (ISRO) has added another feather to its cap. The satellite will enhance India’s capability in crop monitoring during the monsoon season, forestry mapping for forest fires and deforestation, and flood mapping as part of the national disaster management programme. Given that overcast skies are a constant during the monsoon season and during times of flood, the ability to penetrate the cloud cover is essential. While optical remote sensing that relies on visible light for imaging gets obstructed by clouds, RISAT-2B will not. Much like the RISAT-1 satellite that was launched by ISRO in April 2012, RISAT-2B will also use microwave radiation. Unlike visible light, microwaves have longer wavelength and so will not be susceptible to atmospheric scattering. Microwave radiation can thus easily pass through the cloud cover, haze and dust, and image the ground. Hence, RISAT-2B satellite will be able to image under almost all weather and environmental conditions. Since it does not rely on visible light for imaging, it will be able to image the ground during both day and night. The satellite does not have passive microwave sensors that detect the radiation naturally emitted by the atmosphere or reflected by objects on the ground. Instead, RISAT-2B will be transmitting hundreds of microwave pulses each second towards the ground and receiving the signals reflected by the objects using radar. The moisture and texture of the object will determine the strength of the microwave signal that gets reflected. While the strength of the reflected signal will help determine different targets, the time between the transmitted and reflected signals will help determine the distance to the object.
The RISAT-2B satellite uses X-band synthetic aperture radar for the first time; the synthetic aperture radar was developed indigenously. Unlike the C-band that was used by RISAT-1, the shorter wavelength of the X-band allows for higher resolution imagery for target identification and discrimination. Since it has high resolution, the satellite will be able to detect objects with dimensions of as little as a metre. This capacity to study small objects and also movement could be useful for surveillance. As K. Sivan, ISRO Chairman and Secretary, Department of Space, had said last month, the satellite could be used for civil and strategic purposes. RISAT-2B will have an inclined orbit of 37 degrees, which will allow more frequent observations over the Indian subcontinent. With ISRO planning to launch four more such radar imaging satellites in a year, its ability to monitor crops and floods as well as engage in military surveillance will be greatly enhanced.
India this morning successfully launched a new "spy satellite" capable of keeping a lookout from space even in cloudy conditions, leaving no room for doubt the next time its armed forces conduct an operation such as the Balakot air strike carried out earlier this year.
The Indian Space Research Organisation (ISRO) used its Polar Satellite Launch Vehicle to launch the 615-kg RISAT-2B satellite, capable of clear viewing during the day, night and even under adverse weather conditions, at 5:30 am on Wednesday. ISRO chief Dr K Sivan called the launch of RISAT-2B a "fantastic mission". The home-grown space agency has sent 354 satellites into orbit and crossed a landmark of lifting a total of over 50 tonne of material into the space.
Dr Sivan announced that RISAT-2B has "special imaging capabilities to take strips of images and mosaics of images". The launch also saw the use of made-in-India Vikram Processor for the first time, realised by the semiconductor complex at Chandigarh.
Defence Minister Nirmala Sitharaman tweeted after the launch.
The special radar-enabled satellite has been placed at a low earth 557-kilometre orbit, a suitable level for detecting hostile installations as well as monitoring agriculture, forestry and possible disaster zones. The space agency did not release details or photographs of the satellite, considering that it is meant for strategic needs.
The Indian Air Force (IAF) had sent Mirage 2000 fighter jets to strike a terror camp in Balakot, deep inside Pakistan territory, on the morning of February 26. Some experts have speculated that heavy cloud cover at the time could have blinded Indian satellites, resulting in no images or videos of the operation being released so far. The lack of "proof" even spurred some opposition leaders to question the actual impact of the air strike.
Now, with a new set of radar-enabled satellites at its disposal, the space agency hopes to provide India's armed forces with the ability to keep track of activities across its eastern and western borders. Although the country also has high-resolution optical imaging CartoSAT satellites, they get blinded by dense cloud cover. Moreover, their imaging resolution was possibly not good enough to make an accurate damage assessment after the IAF strike in Balakot.
The RISAT-2B, a satellite created at the Space Applications Centre in Ahmedabad, is equipped with a special X-band radar capable of providing much better images. This is the first time India has launched indigenous technology of this kind into the space.
Two previous radar-enabled satellites launched by India into space were RISAT-1 and RISAT-2, the latter being an acquisition from Israel. The RISAT-1, a C-band radar imaging satellite, was not available for recording the impact of the Balakot strikes because it was declared dead in 2017. However, there is no clarity on why images from the RISAT-2, a tiny 300 kg satellite with an X-band radar launched in the wake of the 2008 Mumbai attacks - have not been released.
Incidentally, Pakistan had launched the PAKTES 1A satellite - also supposed to be an X-band radar-enabled satellite - using a Chinese Long March rocket on July 9 last year.
The launch of RISAT-2B was realised in 15 months and it has a life of five years, and if all goes well, two clones - RISAT-BR1 and RISAT-2BR2 - will be launched in the coming months. Some of these launches have been advanced by as many as 18 months, reliable sources in the ISRO confirmed.
Sources: Online News Articles
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