Tsiolkovsky weirdness

[KvickFlygarn87]

Please note that all this is purely theoretical.

If I were to have engines with the same Isp and 0 mass, would I lose delta v from adding more of these? My guess is no, since you only lose dv because you add mass normally. Or am I wrong?

[DonLorenzo]

Nope, you're right. 0 mass engine same ISP makes no difference in dV

[Ralathon]

What DonLorenzo said. If you have access to massless engines you should add as many as possible, you would gain thrust and lose nothing.

Sadly massless engines don't exist in real life because everything with 0 mass has to move at the speed of light.

[jrphilps]

What DonLorenzo said. If you have access to massless engines you should add as many as possible, you would gain thrust and lose nothing.

Sadly massless engines don't exist in real life because everything with 0 mass has to move at the speed of light.

Is handwavium allowed here? If so, then maybe you can arrange for negative matter to cycle through the engine, and effectively make it weightless? Or, you could have a mass lightning field (ala star trek) with a variable geometry, so that everything but the engine and propellant have a negligible mass.

[Ralathon]

Is handwavium allowed here? If so, then maybe you can arrange for negative matter to cycle through the engine, and effectively make it weightless? Or, you could have a mass lightning field (ala star trek) with a variable geometry, so that everything but the engine and propellant have a negligible mass.

If you have negative mass you won't need engines at all. Just make a sphere of negative mass and a sphere of positive mass. Charge them with a electric field so they attract one another and off you go. Action = reaction, but since the mass for one sphere is negative the acceleration must also be negative (F=ma), so both your spheres will accelerate in the same direction. Just bolt them down and enjoy infinite acceleration.

And if you have access to fields that allow you to adjust the weight of objects I'm sure you can do better than merely making your ship lighter. Changing the mass of objects allows you to violate conservation of momentum. You could, for example, get some energy by running water past a waterwheel, then activate your magical mass lightener and lift the water back to its original height for a fraction of the energy you got from the wheel. Infinite energy ahoy. If you have access to that kind of power you can abuse that in much better ways. You could lighten your propellant to easily accelerate it to near light speed and then turn the field off to get insane Isp without losing on thrust. Or you can make the interstellar gas in front of your ship super heavy so the gravity pulls you forward.

[MC.STEEL]

Alas the power requirements for this device would far outway any sort of advantage you would get from it.

(I am on the theory that if you put enough energy in the correct manner everything is possible.)

[BlackBicycle]

Just going along with the theory... okay,massless, but they do have atmospheric resistance, right? Or are we dealing with the classic ''spherical horse in vacuum'' case?