From what I’ve read so far, a space elevator’s counterweight must extend beyond geostationary orbit in order to keep tension on the tether. If you’re higher than GEO, your orbital period will be longer than a day, so how is the counterweight kept stationary when it’s higher than GEO?
In: Physics
the idea with a space elevator is that you counter weight with an object ABOVE geostationary orbit. as you get higher the orbital speed drops AND orbital duration increases. so an object at geostationary orbit is travelling at 3.3km/sec. an object further out but keeping station with it would have to travel a bit faster, but for the sake of simpolicity lets say its the same. geostatrionaary orbit is 35000km give or take. if we put a weight at 50,000km its orbital velocity to be in a circular orbit is 2.8km/s, but it has to be moving faster than 3.3km/s to keep up with the earths surface. this means it wants to fly out into a higher (excentric) orbit but it cant because its tied to the earth. this then applies the tension to keep the tether upright. but it is worth considering the energy for something getting to geostationary orbit has to come from somewhere. there is potential energy from hauling yourself up there but also kinetic energy because you are getting faster to maintain the same orbital period at greater radii. so the counterwieight must have some form of boosting or retrograde engines depending on if more mass is going up or coming down. (coming down the payload would try and overtake the cable as its going 3km/s but the ground is only going 0.4km/sec
Latest Answers