Mars Academy

Low Earth Orbit

Although parking a spacecraft in low earth orbit is by no means a simple task, almost all space missions so far have involved placing a spacecraft is terrestrial orbit. There are no technological problems involved and the only requirement would be an efficient propulsion system capable of delivering the thrust required to overcome Earth's gravity and obtain the velocity needed to achieve the desired orbit.

As we have seen, the velocity needed to obtain an orbit of height r is :

V= [G . Me / (R+r)]^1/2

where Me is the mass of the Earth, R is the radius of the Earth and r the height of the desired orbit.

For the first stage of the trajectory, that is, the Earth's surface to Low Earth Orbit, the change in velocity is determined and so the next step simply implies choosing a propulsion system capable of delivering the required mass to Earth orbit.