Question

I was thinking of the trading of kinetic energy during a gravitational slingshot maneuver and wondered if the kinetic energy lost during that process makes any noticeable impact on the orbit of the planet. Since the planet we are performing this maneuver on loses kinetic energy, it is realistically possible to do enough slingshots that we noticeably change the orbit of the planet? And what would be the consequences of changing the orbit?

Answer 1

The effect of a gravitational slingshot on a planet's orbit is negligible due to the large difference in mass between the planet and the spacecraft. Substantial alteration of Earth's orbit, for example by asteroid flybys, could theoretically move Earth outward but requires extreme precision. The difference in potential versus kinetic energy for satellites changes with the size of the orbit.

Step-by-step explanation:

The concept of using a gravitational slingshot to change a spacecraft's trajectory involves the transfer of kinetic energy between a planet and the spacecraft. During the maneuver, the spacecraft gains speed and the planet loses a tiny amount of its own kinetic energy due to the conservation of momentum. However, this energy change is minuscule compared to the planet's total energy, making the impact on the planet's orbit practically negligible. Realistically, performing enough slingshots to noticeably change a planet's orbit would require an infeasible number of maneuvers over an exceptionally long timescale.

If we were to redirect an asteroid between Earth and Jupiter, as proposed, it could transfer orbital energy from Jupiter to Earth. This could theoretically move Earth slowly outward and help counteract the effects of the Sun's expansion. Such a process would need to be managed with extreme precision to avoid catastrophic collisions and ensure that the orbit change is gradual enough to be absorbed by the Earth's systems without causing immediate harm to its inhabitants and environment. A satellite's orbit, whether it's bound or unbound, depends on its total energy. If the total energy, which is the sum of the satellite's kinetic energy and gravitational potential energy, is negative, the satellite is in a bound orbit. Otherwise, it's in an unbound orbit. In the case of increasing the size of an orbit, the ratio of kinetic energy to the change in potential energy becomes relevant. The larger the orbit, the greater the potential energy change required to boost the satellite to that orbit, compared to the kinetic energy needed to maintain it.