Question

1) What is an artificial satellite? Name any two types of artificial satellite and sate
their functions.​

Answer 1

Answer:

An artificial satellite is an object that people have made and launched into orbit using rockets. There are currently over a thousand active satellites orbiting the Earth. The size, altitude and design of a satellite depend on its purpose.

What are satellites?

Dr Allan McInnes tells us what a satellite is, how they vary in size and, depending on their function, the type of orbit they are placed into.

Sizes and altitudes of satellites

Satellites vary in size. Some cube satellites are as small as 10 cm. Some communication satellites are about 7 m long and have solar panels that extend another 50 m. The largest artificial satellite is the International Space Station (ISS). The main part of this is as big as a large five-bedroom house, but including solar panels, it is as large as a rugby field.

Altitudes of satellites above the Earth’s surface also vary. These are three common orbits:

Low Earth orbit (LEO) – from 200 to 2,000 km, for example, the ISS orbits at 400 km with a speed of 28,000 km/hour, and time for one orbit is about 90 minutes.

Medium Earth orbit (MEO) – most MEO satellites are at an altitude of 20,000 km, and time for one orbit is 12 hours.

Geostationary orbit (GEO) – 36,000 km above the Earth. Time for one orbit is 24 hours. This is to match the rotation of the Earth so that the satellite appears to stay above the same point above the Earth’s surface. This is used for many communications and weather satellites.

The altitude chosen for a satellite depends on the job it is designed for.

Types of satellites

Navigation satellites

The GPS (global positioning system) is made up of 24 satellites that orbit at an altitude of 20,000 km above the surface of the Earth. The difference in time for signals received from four satellites is used to calculate the exact location of a GPS receiver on Earth.

Communication satellites

These are used for television, phone or internet transmissions, for example, the Optus D1 satellite is in a geostationary orbit above the equator and has a coverage footprint to provide signals to all of Australia and New Zealand.

Answer 2

Artificial satellite is a man-made device orbiting around the earth, moon or another planet transmitting to earth scientific information or used for communication.

These satellite revolve around the planets and prvided all the information about planet through satellite imagery.

Two types of artificial satellites :

1) Weather satellite : Help to predict weather.

ex. TIROS, COSMOS

2) Communication satellite :

Allow telephone and data conversations to be relayed through satellite

ex. Telstar, Intelsat.