Question

i) Explain the difference between a man-made and a natural satellite.

ii) State two important advantages of weather satellites.

iii) Starlink is a satellite constellation being constructed by SpaceX to provide global satellite Internet access. The constellation will consist of thousands of small satellites in low earth orbit. A Starlink launch to an altitude of 550km is required. The Falcon 9 launcher delivers 9.0 metric tonnes payload into a LEO orbit. The lift-off mass is 318 tonnes. The U of the exhaust gases is 2.4 km s^-1     

Use the equation ∆V = U ln (M_i /(M_i-M_f)) to calculate ∆V (3sf)

iv) For a satellite orbiting Earth the force of attraction between the Earth and a satellite is expressed by:

F=GM₁ x M₂/d²       Where F is the force of attraction

M₁ the larger mass of the Earth        

M₂ the satellite mass G the Gravitational constant

D the distance from the centre of the Earth to the centre of the satellite.     

                                       

Calculate the velocity required for a satellite in a circular orbit 300km above the earth’s surface.

The radius of the Earth R_E ~ 6400 km (1 decimal place).

Note: In circular orbit at the Earth's surface F= M₂v²/r = M₂g

v) What affect does increasing distance have upon the circular velocity required to keep a satellite in a circular orbit, and what may result as a consequence?

6. The period of a satellite (T) and the mean distance from the central body (R) are related by the following equation:

T2R3=4π2GMEarth

where T is the period of the satellite, R is the average radius of orbit for the satellite (distance from centre of Earth), and G = 6.673 x 10^-11 N m²/kg² .

M_earth = 5.98x10²⁴ kg         R = R_earth + height = 6.7 x 10⁶ m

Find the acceleration (2dp) and the period of the satellite.

Answer 1

1. Man made satellites are satellites which are build by us by using the technology around us. We usually deploy it to move around Earth at very close orbits. It is used for communications, remote sensing..etc. Natural satellites are satellites that are celestial objects which revolves arounf planets, it was created long time ago (usually during the creation phase of planet). The reason for the creation will be due to natural causes only. Examples is Moon which is a natural satellite of Earth.