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.
