Current Affairs

GK MCQs Section
Q. Satellites used for telecommunication relay are kept in a geostationary orbit. A satellite is said to be in such an orbit when:
  1. The orbit is geosynchronous.
  2. The orbit is circular.
  3. The orbit lies in the plane of the Earth's equator.
  4. The orbit is at an altitude of 22236 km
Select the correct answer using the codes given below : (UPSC Prelims 2011)
Answer: 1, 2 and 3 only
Notes:
  • 1. The orbit is geosynchronous (Correct): A geosynchronous orbit has an orbital period that matches Earth's rotation (approximately 23 hours, 56 minutes, and 4 seconds). While all geostationary orbits are geosynchronous, not all geosynchronous orbits are geostationary.
  • 2. The orbit is circular (Correct): For a satellite to maintain a constant speed that matches the Earth's surface rotation speed exactly, the orbit must be circular. If it were elliptical, the satellite would speed up and slow down at different points, moving back and forth relative to the ground.
  • 3. The orbit lies in the plane of the Earth's equator (Correct): This is the defining characteristic of a "Geostationary" orbit. By orbiting directly over the equator, the satellite stays at 0 degrees latitude. If it were inclined, it would appear to move north and south in the sky.
  • 4. The orbit is at an altitude of 22,236 km (Incorrect): This is a common "trick" number. The actual altitude required for a geostationary orbit is approximately 35,786 km (often rounded to 36,000 km). At 22,236 km, the satellite would orbit the Earth much faster than the Earth rotates.