News highlight
The Indian Space Research Organisation (ISRO) said the satellites onboard its maiden Small Satellite Launch Vehicle (SSLV) “are no longer usable” after the SSLVD1 placed them in an elliptical orbit instead of a circular one.
Key news takeaways
- The ISRO’s new rocket was carrying earth observation satellites EOS-02 and AzaadiSat.
- The SSLVD1 placed the satellites into a 356×76 km elliptical orbit instead of a 356km circular orbit.
Small Satellite Launch Vehicles (SSLV)
- The is designed to serve a market for small satellite launches into low-Earth orbit.
- It has the payload capacity to deliver 600 kg to low Earth orbit or 300 kg to Sun-synchronous orbit (500 km) for launching small satellites, with the capability to support multiple orbital drop-offs.
- The Small Satellite Launch Vehicle (SSLV) is a three-stage all-solid vehicle.
- It offers a quick turnaround time, the ability to accommodate numerous satellites, the ability to launch on demand, and minimal launch infrastructure requirements, among other advantages.
Difference between PSLV and GSLV.
- The PSLV (Polar Satellite Launch Vehicle) and GSLV (Geosynchronous Satellite Launch Vehicle) are two rocket launch systems developed by the ISRO, to launch satellites into orbit.
PSLV (Polar Satellite Launch Vehicle) | GSLV (Geosynchronous Satellite Launch Vehicle) |
PSLV can only lift a little over a ton of payload to GTO (Geostationary Transfer Orbit). | GSLV is capable of lifting more than double that, with a rated capacity of 2 to 2.5 tons. |
Conventional liquid rocket engines | A cryogenic rocket engine |
The PSLV has 4 stages that alternate between solid and liquid fuels. | GSLV has three stages, with only the first stage having solid fuel. |
More reliable | Less reliable |
Earth Observation Satellites (EOS)
- An Earth observation satellite or Earth remote sensing satellite is a satellite used or designed for Earth observation from orbit.
- It includes spy satellites and similar ones intended for non-military uses such as environmental monitoring, meteorology, cartography and others.
- Earth observation satellites employ Sun-synchronous quasi-periodical orbit.
- Example-RESOURCESAT- 2, 2A, CARTOSAT-1, 2, 2A, 2B, RISAT-1.
Types of Orbit
- Geostationary orbit:
- The geostationary orbit is used for communication, broadcasting and weather satellites.
- This orbit takes a position around the equator at a distance of 36000km from the Earth’s surface.
- Because the satellite moves at the same speed as the Earth’s rotation, the satellite maintains the same position over a certain point of the Earth’s surface.
- Low Earth Orbit (LEO):
- A low Earth orbit (LEO) is, as the name suggests, an orbit relatively close to Earth’s surface.
- It is normally at an altitude of less than 1000 km but could be as low as 160 km above Earth – which is low compared to other orbits but still very far above Earth’s surface.
- Medium Earth orbit (MEO):
- Medium Earth orbit comprises a wide range of orbits between LEO and GEO.
- It is similar to LEO in that it also does not need to take specific paths around Earth, and it is used by a variety of satellites with many different applications.
- Polar orbit and Sun-synchronous orbit (SSO):
- Satellites in polar orbits usually travel past Earth from north to south rather than from west to east, passing roughly over Earth’s poles.
- The satellite in this orbit passes by a particular place on the Earth’s surface at the same local solar time (the orbit plane keeps a constant solar angle), so the satellite observes the exact sunlight reflection from the Earth’s surface.
Pic Courtesy: The Indian Express
Content Source: The Hindu