ISRO, In its 17th flight of India's Polar Satellite Launch Vehicle injected three Satellites viz. RESOURCESAT-2, YOUTHSAT and X-SAT (of Nanyang Technical University, Singapore) into Polar Sun-synchronous orbits on April 20, 2011 from Sriharikota.
I intend to educate the reader on Resourcesat-2 satellite in this post. Next in subsequent posts I intend to enlighten the readers about what is Remote Sensing and how it is carried out using satellites; but presently we concentrate on Resorcesat-2.
The Image shows coverage of this satellite around Earth in about 24 hours on a typical day ( 26Apr2011 in specific )
Notice the following features:
1. The satellite revolves around Earth from pole to pole and makes a revolution in about 100 minutes. ( 101.35 minutes in case of Resourcesat-2 ). The height of the satellite during these orbits is about 800 to 840 Kms.
2. While the satellite is moving from pole to pole the Earth rotates on its axis and this combined motion creates 'spring like ' paths around earth continuously. These paths are very accurate and stable ( they are inclined to equator at about 98.7 degrees ) and more importantly, repeatative.
What we mean by repeatative is that if the satellite has taken a particular path today it will repeat that path very accurately after a certain period of days. ( 24 days in case of Resourcesat-2. )
3. Resourcesat-2 satellite has two main cameras on board called as LISS3 and LISS4. The LISS4 has a swath ( area covered on ground as a strip ) of 70Kms. It has Radiometric resolution ( That means the camera can resolve the reflected radians in 10 bit resolution.
4. Another Camera onboard is AWiFS which has a resolution of 12 bits.
5. In addition there is a unique payload viz. AIS (Automatic Identification System) from COMDEV, Canada as an experimental payload for ship surveillance in VHF band to derive position, speed and other information about ships.
6. A set of Solar Photovoltaic Panels provide electrical energy to satellite by converting solar radiation into electricity. The power is also simultaneously saved in on-board batteries which is used during the period when sunlight is not falling on satellite due to Earth's shadow.