# Launching of artificial satellites [closed]

• Whose theory is used today during launching of artificial satellites, Newton's or Einstein's or any other?
• Which theory is better in launching of artificial satellites and other orbiting bodies, Newton's or Einstein's or any other?
• What is the cause of falling of sky-labs and orbited bodies on earth or leaving of their computed orbits?
• What is advance of perihelion of orbited bodies? And what is the classical cause of this advance of perihelion?

## closed as too broad by John Rennie, DilithiumMatrix, Kyle Kanos, HDE 226868, GertDec 12 '15 at 0:18

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

• We typically prefer one question per post, rather than the 5 you have posted. – Kyle Kanos Dec 12 '15 at 0:06
• might it be homework ? – Fabrice NEYRET Dec 12 '15 at 6:41

The calculations for orbits and transfers are mostly done using Newtonian mechanics non-Newtonian effects are included by adding corrections to the force. The exact orbit/flightpath is usually not reached by pure pre computation but by attitude control (that is, corrections are made based on the observed attitude). The most important corrections are usually not due to general relativity, but due to third bodies, thermal radiation and, for low orbits, atmospheric drag.

However, there are high precision calculations which include many effects (even some relativistic corrections). These are primarily used to be compared with measured data. Discrepancies between calculation and observation are a hint to new physics (or errors in the calculations). One example of this is the flyby anomaly another the Pioneer anomaly.

Relativistic corrections are also important for high precision equipment like the GPS satellites, where you have to consider the gravitational time dilation for their clock signals.

The already mentioned radiation effects are very difficult to model (for example, they are now believed to fully explain the Pioneer anomaly). These radiation effects are one important reason it is not possible to compute years ahead whether an asteroid will closely encounter earth or hit it.

There is one other effect, that can be fully explained in Newtonian mechanics, if one is careful: Higher multipole moments of planets or the sun. As planets and the sun are only approximately spherically symmetric, they have higher multipole moments, that cause deviations from Kepler orbits.

As an example, the perihelion shift of mercury is composed of several effects, and general relativity is only one contribution, as is listed here.

In conclusion: Orbits and flight paths are not achieved by using only precomputed burns of the drive, but rather due to difficult to control minute effects that accumulate some form of attitude control is used for corrections. Actual computations of orbits and flight paths are done by using $\vec F = m \ddot{\vec r}$ and modelling deviations from pure $1/r$-gravity as corrections of the force. Some corrections cannot be predicted precisely in the long term. There is no utility in solving the complex geodesic equations from general relativity, if the relativistic corrections are small and can easily be included as corrections of the force (this method is called perturbation theory).