No, any change in the speed of satellite is going to change the orbital altitude. However, one can change the velocity of a satellite with thrust and not change the altitude. The key is that velocity is a vector quantity (speed and direction). The inclination of the orbit can be changed by thrusting at the proper angles to keep orbit at the same altitude (and same speed)
If you increase spacecraft velocity above circular orbital velocity the orbit changes to eliptical one and the spacraft would start climbing towards apogee. This could be countered by applying thrust radialy towards body it is orbiting. However to do this would require constant fuel expenditure.
Quote from: imfan on 08/05/2017 01:12 pmIf you increase spacecraft velocity above circular orbital velocity the orbit changes to eliptical one and the spacraft would start climbing towards apogee. This could be countered by applying thrust radialy towards body it is orbiting. However to do this would require constant fuel expenditure.Would you have a reference in the litterature that explicitely states this ?Thanks
Quote from: Jim on 08/05/2017 12:57 pmNo, any change in the speed of satellite is going to change the orbital altitude. However, one can change the velocity of a satellite with thrust and not change the altitude. The key is that velocity is a vector quantity (speed and direction). The inclination of the orbit can be changed by thrusting at the proper angles to keep orbit at the same altitude (and same speed)Actually only the same orbital plane interest me.Do you mean that if I stay in the same orbital plane, any speed change will change the orbit for an ellipse (or parabola or hyperbola), but if I want to change the orbital plane I can make it with an appropriate thrust ?Would you have a reference in the litterature that explicitely states this (for the same plane) ?Thanks
With continuous thrust, it would be possible to increase speed while remaining on the same circular trajectory. An initial impulse along the direction of motion would accelerate the satellite, and sustained thrust toward the center of the planet would keep it on the original trajectory.
Quote from: Proponent on 08/06/2017 05:25 amWith continuous thrust, it would be possible to increase speed while remaining on the same circular trajectory. An initial impulse along the direction of motion would accelerate the satellite, and sustained thrust toward the center of the planet would keep it on the original trajectory.You use a conditional sentence, so is it an opinion or would you have a reference in the litterature that explains this possibility ?
You keep asking for literature references for things that are simply basic facts about orbital mechanics that people familiar with orbital mechanics clearly understand. If you continuously fire a thruster directly towards the Earth, this adds to the force of gravity, meaning you need a faster velocity to stay in the same circular orbit. Combined with an initial impulse to increase your velocity, you could travel faster while maintaining the same orbit at least until you run out of fuel.This kind of idea is the only way to travel from one side of the Earth to the exact opposite in less than about 45 minutes.
Sorry to ask for references but the answers above are contradictory, and the link that I give above says that you can not stay on the circular orbit by thrusting in any direction. So who should I believe ?
Quote from: meberbs on 08/07/2017 03:02 pmYou keep asking for literature references for things that are simply basic facts about orbital mechanics that people familiar with orbital mechanics clearly understand. If you continuously fire a thruster directly towards the Earth, this adds to the force of gravity, meaning you need a faster velocity to stay in the same circular orbit. Combined with an initial impulse to increase your velocity, you could travel faster while maintaining the same orbit at least until you run out of fuel.This kind of idea is the only way to travel from one side of the Earth to the exact opposite in less than about 45 minutes.Sorry to ask for references but the answers above are contradictory, and the link that I give above says that you can not stay on the circular orbit by thrusting in any direction. So who should I believe ? As far as I know in science any statement has to be proven, with either a demonstration or a reference of the literature. Do you think that I could refere to your post in a scientific paper that only says "meberbs, at forum.nasaspaceflight.com, stated so" ? I would be very happy if I could but I figure out that it won't do it.This is why I am looking for references. Sorry for that.
hclatomic,You wouldn't be trying to get us to do your homework for you, would you?
I need solid references to include into a paper. I am ready to believe anything you tell me here, but my belief won't be enough. I am searching everywhere on the internet but I can not find nowhere a scientific description of a thrusted satellite that remains on its circular orbit.At the contrary all the books and paper are describing thrusts that change the orbit, wether the thrust is impulsional or low and continuous.
This is why I ask you here if you can drive me to formal scientific evidences and demonstrations of how to perform a satellite acceleration by staying on the same circular orbit.