It seems to me that gravity would be operating on the center of mass to bust the concept.
... a mass at a given orbital height that is moving faster than circular orbit for that height ...Similarly, a mass moving at less than orbital velocity for that altitude.... No expelled propellant, just energy to keep the tether and masses spun up.
Considering the system angular momentum is always conserved, and the mechanical energy is conserved only with invariant tether length...
So yeah, incomplete system characterization. And I suspect your 650s ISP engine falls into a similar trap as well.
Quote from: 1 on 01/07/2023 12:06 amSo yeah, incomplete system characterization. And I suspect your 650s ISP engine falls into a similar trap as well. https://selenianboondocks.com/2008/10/tetherocket/I'll bite on this one. With the caveat that theoretically possible is not the same as technically and financially feasible.
Quote from: redneck on 01/07/2023 09:26 amQuote from: 1 on 01/07/2023 12:06 amAnd here, we see the system break. If you fire the one blue rocket from 8 to 10 as normal, you get your exhaust velocity of 7.5km/s relative to system center distant observer as stated. However, the rocket firing from 2 to 4 only gets an exhaust velocity of 1.5km/s. So if the perceived benefits of the tether rocket were real, this system should still accelerate forward, and do so very rapidly. If all reference frames do not agree on what would happen to the system, then it's a clear indication that the system has not been fully characterized. I think you are missing that the rocket only fires in pulses when the vectors line up. The blue never fires other than the 8 to 10 position as the yellow only fires from the 2 to 4 position. If it wasn't clear in the post, it was certainly made clear in comments. Several people had the same visualization problem with the concept.
Quote from: 1 on 01/07/2023 12:06 amAnd here, we see the system break. If you fire the one blue rocket from 8 to 10 as normal, you get your exhaust velocity of 7.5km/s relative to system center distant observer as stated. However, the rocket firing from 2 to 4 only gets an exhaust velocity of 1.5km/s. So if the perceived benefits of the tether rocket were real, this system should still accelerate forward, and do so very rapidly. If all reference frames do not agree on what would happen to the system, then it's a clear indication that the system has not been fully characterized. I think you are missing that the rocket only fires in pulses when the vectors line up. The blue never fires other than the 8 to 10 position as the yellow only fires from the 2 to 4 position. If it wasn't clear in the post, it was certainly made clear in comments. Several people had the same visualization problem with the concept.
And here, we see the system break. If you fire the one blue rocket from 8 to 10 as normal, you get your exhaust velocity of 7.5km/s relative to system center distant observer as stated. However, the rocket firing from 2 to 4 only gets an exhaust velocity of 1.5km/s. So if the perceived benefits of the tether rocket were real, this system should still accelerate forward, and do so very rapidly. If all reference frames do not agree on what would happen to the system, then it's a clear indication that the system has not been fully characterized.