Risat-1 'Spy Satellite' Launched

In 2009, the Indian Space Research Organisation (ISRO) had launched the RISAT-2, a spy satellite acquired from Israel for $110 million. In the last week of April this year, ISRO successfully launched from the Satish Dhawan Space Centre, Sriharikota, its first indigenously produced “spy satellite” RISAT-1, aboard the Polar Satellite Launch Vehicle (PSLV) C19. It inserted the 1,858-kg radar imaging satellite into a polar circular orbit at an altitude of 480 kilometres and an orbital inclination of 97.552 degrees. The mission was proclaimed to be a grand success. RISAT-1 has day and night capability and can see through cloud cover or any other atmospheric obscurity. Orbiting the Earth 14 times a day, it will give India continuous surveillance capability. Meant primarily for a number of civilian applications, the all-weather surveillance tool can also function as a “spy satellite”. RISAT-1 carries a C-band Synthetic Aperture Radar operating in a multi-polarisation and multi-resolution mode and can provide images with coarse, fine and high spatial resolutions of about one metre. It has a mission life of five years.
Here are the top 10 facts on RISAT-1:

1. Weighing at 1858 Kg, RISAT-1 is the heaviest satellite ever launched by India.
2. It was powered by a 321 tonne rocket, the most powerful Polar Satellite Launch Vehicle (PSLV).

3. This is the third time that ISRO used a PSLV-XL (Extra Large) rocket. It was first used in October 2008 to put Chandrayaan-1 in orbit and again in July 2011 during the communication satellite GSAT-12 launch.

4. The indigenously made satellite has day and night viewing capacity and will not be blinded by cloud cover. 
5. RISAT-1 will help in crop monitoring and flood forecasting. It will give India the ability for continuous surveillance.

6. The satellite carries a C-band Synthetic Aperture Radar (SAR) payload, operating in a multi-polarisation and multi-resolution mode to provide images with coarse, fine and high spatial resolutions. It has a best resolution of up to 1 m

7. It has taken ISRO 10 years to make this sophisticated satellite. So far PSLV has consecutive 19 successful launches. 
8. The total cost of mission is about 
Rs. 500 crores. While the cost of the rocket is about Rs. 120 crores, the satellite costs around Rs. 380 crores. However, none of them are insured.
9. The project Director N Valarmathi, is the first woman to head a remote sensing satellite project, and the second to be the satellite project director at ISRO.
10. Apart from RISAT-1, India already has another spy satellite RISAT-2 acquired from Israel which was launched in 2009.

The indigenously built RISAT-1, with a life span of five years, will be used for disaster prediction and agriculture forestry. The high resolution pictures and microwave imaging from RISAT-1 could also be used for defence purposes as it can look through the clouds and fog.

At 5.47 a.m., the rocket - Polar Satellite Launch Vehicle C19 (PSLV-C19) - standing 44.5 metres tall and weighing 321 tonnes and with a one-way ticket, hurtled towards the skies ferrying the 1,858 kg RISAT-1 after unshackling itself from launch pad No.1.

The ISRO-made RISAT-1 is the heaviest luggage so far ferried by a PSLV since 1993.

At around 17 minutes into the flight, PSLV-C19 delivered RISAT-1 into a polar circular orbit at an altitude of 480 km and an orbital inclination of 97.552 degrees.

ISRO, with its network of ground stations, monitored its health.

"PSLV-C19 mission is a grand success. This is the 20th successive successful flight of PSLV. India's first radar imaging satellite was injected precisely into orbit," ISRO chairman K. Radhakrishnan said after the launch. "With this launch India joins a select group of nations like the US, Canada, Europe and others to have such an advanced technology. It is a 30 year effort," he added.

"With RISAT-1 we can now forecast Kharif season," Dr Radhakrishnan said.

According to satellite director N. Valarmathi, RISAT-1 can take images in all weather conditions and during day and night. "The satellite has high storage device and other several unique features," she added.

For ISRO, this is the first launch this fiscal as well as in the calendar year.

According to Dr Radhakrishnan, the Indian space agency is planning couple of more satellite launches - communication and remote sensing satellites - this year. He said the space agency would launch a communication satellite weighing 3.5 tonne through the Ariane rocket from French Guiana and two PSLV missions were scheduled for later this year. ISRO will also send SARAL satellite - an Indo-French initiative - using its PSLV rocket from Sriharikota. There will also be the launch of first Indian regional navigational satellite this fiscal.

Speaking about the status of the space agency's heavy rocket - Geosynchronous Satellite Launch Vehicle (GSLV) - that can carry communication satellites, Dr Radhakrishnan said the advanced rocket GSLV Mark III has crossed several milestones and an experimental flight will be made in a year from now.

He said the experimental flight will be to test the rocket systems in the atmospheric flight phase.

The Indian made cryogenic engine is also undergoing several tests.

Meanwhile, the solar panes of RISAT-1 were deployed successfully soon after it was injected into the orbit.

According to Dr Radhakrishan, in three days time the satellite will be taken up to its intended orbit at an altitude of 536 km by firing the on-board motors.

Remote sensing satellites send back pictures and other data for use. India has the largest constellation of remote sensing satellites in the world providing imagery in a variety of spatial resolutions, from more than a metre ranging up to 500 metres, and is a major player in vending such data in the global market.

With 11 remote sensing/earth observation satellites orbiting in the space, India is a world leader in the remote sensing data market. The 11 satellites are TES, Resourcesat-1, Cartosat-1, 2, 2A and 2B, IMS-1, Risat-2, Oceansat-2, Resourcesat-2 and Megha-Tropiques.

RISAT-1's synthetic aperture radar (SAR) can acquire data in C-band and would orbit the earth 14 times a day.

In 2009, ISRO had launched 300 kilogram Risat-2 with an Israeli-built radar enabling earth observation in all weather, day and night conditions.

With Thursday's launch the PSLV rocket has launched successfully 53 satellites out of 54 it carried - majorly remote sensing/earth observation satellites both Indian and foreign - and has been a major revenue earner for ISRO.

The one failure happened in 1993 when the satellite was not able reach the orbit.

The rocket that delivered RISAT-1 in the space is ISRO's four stage PSLV's upgraded variant called PSLV-XL.

The letters XL stand for extra-large as the six strap-on motors hugging the rocket at the bottom can carry 12 tonnes of solid fuel as against the base version that has a fuel capacity of nine tonnes.

The PSLV's four stages are fuelled with solid and liquid propellants. The first and third stages are fuelled by solid fuel, while the second and fourth stages are powered by liquid fuel.

ISRO had used the PSLV-XL variant for its Chandrayaan-1 moon mission in 2008 and for launching the GSAT-12 communications satellite in 2011.

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