Space Technology in India
NCERT Class 11 • Geography • Chapters on remote sensing | NCERT Class 8 • Science • Chapter "Stars and the Solar System"
Space Technology in India
India's space programme was built around a simple idea: space technology should be used to solve problems on the ground. That is why it has concentrated on communication, weather forecasting, remote sensing and navigation rather than on prestige alone.
Satellites, Launch Vehicles and Orbits
- A satellite is any object placed in orbit around a planet; the moon is a natural satellite and the rest are artificial.
- Communication satellites relay telephone, television, internet and broadcasting signals over long distances.
- Remote sensing satellites photograph the earth's surface for mapping, crop assessment, forest cover, mineral survey and disaster management.
- Weather satellites track clouds, cyclones and rainfall and make early warning possible.
- Navigation satellites give position information, which is used in transport, fishing, surveying and mobile applications.
- A geostationary orbit lies above the equator at a height where the satellite circles the earth in exactly one day, so it appears fixed over one spot.
- A polar or sun synchronous orbit is much lower and passes over the poles, which lets a satellite cover the whole earth strip by strip.
Uses and Benefits
- Cyclone warning from weather satellites has sharply reduced loss of life on the east coast.
- Crop forecasting helps plan procurement, storage and import decisions well before harvest.
- Tele education and telemedicine carry teaching and medical advice to remote areas.
- Disaster management uses satellite images to plan relief after floods, earthquakes and landslides.
- Mapping and survey of land, water bodies, forests and minerals now depends almost entirely on satellite data.
- Launch vehicles carry satellites into orbit using multiple stages, each of which falls away once its fuel is used.
- India has also undertaken missions to the moon and to Mars, which extended its capability into deep space.
| Satellite Type | Main Use | Typical Orbit |
|---|---|---|
| Communication | Television, telephone, internet | Geostationary |
| Remote sensing | Mapping and resource survey | Polar or sun synchronous |
| Weather | Cyclone and rainfall tracking | Geostationary |
| Navigation | Position information | Specialised orbit |
Geostationary orbit — an orbit above the equator in which a satellite takes exactly one day to circle the earth, so it appears stationary from the ground.
Hindi me samjhein
भूस्थिर कक्षा में उपग्रह पृथ्वी के साथ ही घूमता है, इसलिए वह एक ही स्थान पर ठहरा दिखता है। ध्रुवीय कक्षा नीची होती है और उपग्रह पूरी पृथ्वी को पट्टी दर पट्टी ढक लेता है।
Exam me kaise aata hai
- A satellite that appears fixed over one spot is in — geostationary orbit
- Satellites that photograph the earth's surface are — remote sensing satellites
- Cyclone warning comes from which satellites — weather satellites
- The moon is what kind of satellite — a natural satellite
UPSC/State PSC ke liye
- A geostationary satellite must be above the equator, because only there does a one day orbit keep it over the same point on the ground.
- Remote sensing needs a low polar orbit for resolution, while communication needs a high equatorial orbit for coverage, which is why the two use different orbits.
Yahan confuse hote hain
✗ All satellites are artificial | The moon is a natural satellite | ✓
✗ A geostationary satellite does not move | It moves with the earth, so it appears fixed | ✓
✗ Remote sensing satellites are placed in geostationary orbit | They use polar or sun synchronous orbits | ✓
Ek nazar me
- Satellites are communication, remote sensing, weather or navigation type.
- Geostationary orbit lies above the equator; polar orbit covers the whole earth.
- Uses include cyclone warning, crop forecasting, telemedicine and disaster relief.
- Launch vehicles use multiple stages to reach orbit.