Satellites — Set 2

Correct Answer: D. INSAT

The Indian National Satellite (INSAT) system is a multipurpose system for telecommunications and weather forecasting. It helps in disaster warning and search and rescue operations. It is one of the largest domestic communication satellite systems in the Asia-Pacific region.

Correct Answer: C. A device that receives and retransmits signals

Transponders are the core components that handle the data traffic for communication satellites. They receive signals from Earth, amplify them, and change their frequency before sending them back. A single satellite can carry dozens of these devices.

Correct Answer: A. Medium Earth Orbit

Medium Earth Orbit (MEO) is the region between 2,000 km and 35,786 km. GPS satellites operate here at an altitude of about 20,200 km. This altitude provides a good balance between signal strength and coverage area.

Correct Answer: C. High-resolution Earth mapping

Cartosat satellites are part of the Indian Remote Sensing program used for cartographic applications. They provide high-quality images for urban planning and resource management. They are often referred to as 'eyes in the sky' for India.

Correct Answer: D. Gravitational force

The correct answer is 'Gravitational force'. The Earth's gravity pulls the satellite toward it, while the satellite's forward velocity keeps it moving in a curve. This balance prevents the satellite from flying into space or falling to the ground. It is similar to how the Earth orbits the Sun.

Correct Answer: C. The functional instruments on the satellite

The payload includes the specific tools like cameras, sensors, or transponders that perform the mission. It is distinct from the satellite 'bus', which provides power and structural support. The choice of payload depends on whether the satellite is for weather, science, or communication.

Correct Answer: C. India

India launched EDUSAT (GSAT-3) in 2004 specifically for the curriculum-based education sector. It was intended to provide interactive satellite-based distance education to rural areas. This was a unique initiative to use space technology for social development.

Correct Answer: A. Space debris accumulation

Kessler Syndrome is a scenario where the density of objects in LEO is high enough that collisions cause a cascade. This could create a belt of debris that makes space activities and satellite use impossible for generations. It is a major concern for long-term space sustainability.

Correct Answer: C. ISRO

Bhuvan is ISRO's Indian Geo-Platform which allows users to explore a 2D/3D representation of the Earth. It provides thematic maps related to water, agriculture, and land cover. It serves as an Indian alternative to platforms like Google Earth.

Correct Answer: D. Monitoring Earth's entire surface over time

Polar satellites orbit over the North and South Poles while the Earth rotates underneath them. This allows the satellite to eventually map every part of the globe. They are widely used for reconnaissance, weather forecasting, and environmental studies.