Topics Covered:
Awareness in space.
RISAT-2BR1
What to study?
For Prelims and mains: Features of RISAT- 2BR1, about PSLV and GSLV.
Context: India’s Polar Satellite Launch Vehicle, in its fiftieth flight (PSLV-C48), has successfully launched RISAT-2BR1 along with nine commercial satellites from the Satish Dhawan Space Centre (SDSC) SHAR, Sriharikota.
This is PSLV’s 50th successful mission and the 75 thlaunch vehicle mission from SDSC SHAR, Sriharikota.
What is RISAT-2BR1?
It is a radar imaging earth observation satellite.
It provides services in the field of agriculture, forestry and disaster management.
Its mission life is 5 years.
Other satellites on board:
The nine customer satellites were from Israel, Italy, Japan and the USA.
These satellites were launched under a commercial arrangement with New Space India Limited (NSIL).
Background:
The RISAT, which was first deployed in orbit on April 20, 2009 as the RISAT-2, uses synthetic aperture radars (SAR) to provide Indian forces with all-weather surveillance and observation, which are crucial to notice any potential threat or malicious activity around the nation’s borders.
Following the 2008 Mumbai terror attacks, the launch of RISAT-2 was prioritised over RISAT- 1, as its C-band SAR radar was not yet ready and RISAT -2 carried an Israeli-built X-band radar.
What is PSLV?
Polar Satellite Launch Vehicle is an indigenously-developed expendable launch system of the ISRO.
- It comes in the category of medium-lift launchers with a reach up to various orbits, including the Geo Synchronous Transfer Orbit, Lower Earth Orbit, and Polar Sun Synchronous Orbit.
Difference between PSLV and GSLV:
India has two operational launchers- Polar Satellite Launch Vehicle (PSLV) and Geosynchronous Satellite Launch Vehicle (GSLV).
GSLV was developed to launch the heavier INSAT class of geosynchronous satellites into orbit.
Different orbits:
There are three main types of Earth orbits- high Earth orbit, medium Earth orbit and low Earth orbit. Which orbit a particular satellite is placed in depends on its function.
- When satellites are about 36,000 km from the Earth’s surface, they enter what is called the high Earth orbit.Here, it orbits in sync with the Earth’s rotation, crating the impression that the satellite is stationary over a single longitude. Such a satellite is said to be geosynchronous.
- Just as the geosynchronous satellites have a sweet spot over the equator that allows them to stay over one spot on Earth, polar-orbiting satellites have a sweet spot that allows them to stay in one time. This orbit is a Sun-synchronous orbit,which means that whenever and wherever the satellite crosses the equator, the local solar time on the ground is always the same.
Sources: the Hindu.
