Alternate Propulsion Systems

[ComatoseJedi]

Let's face it, I love mods. Most of all, I love the ideas of near future technology mods. A big thanks to @Nertea @RoverDude @FreeThinker @Angel-125 and whomever else does these things, your work is very much appreciated and very unique in this game. However, I've been thinking on how to use these mods effectively (other than the warp drives, they are pretty much strait forward). When dealing with electric engines (xenon, argon, thermal, et all), I often wondered why most of these engines have very low thrust in a vacuum. I know that the authors of mods of this nature are often just emulating real world concepts and designs, but how would these technologies move big, interplanetary ships at a reasonable velocity, without having to add several engines to the mix and not to mention the power and fuel to run these things (and heat control). Where's the balance? The faster you want to go, the more you have to add to your ship. The more you add to your ship, the heavier it is. It's a never ending cycle.

To be honest, I haven't really done any research into these technologies on paper, so I may be out of my league to express my confusion. But, is that the concept? A slow burn while using light fuel to achieve velocity goals? So you'll have to really plan for injections into other SOI's? I've read The Martian and the engine in that was 5 mm per second (I think), but it wouldn't go that fast, it would build up speed. The times I have made a ship based on these technologies, the thrust appears to stay constant, instead of progressing in velocity. Or am I not seeing that aspect (if it's even implemented in game). 

Please forgive my ignorance if all these questions have been answered, don't stone me to death, I beg of you. 

 

[hoojiwana]

20 minutes ago, ComatoseJedi said:

A slow burn while using light fuel to achieve velocity goals? So you'll have to really plan for injections into other SOI's? I've read The Martian and the engine in that was 5 mm per second (I think), but it wouldn't go that fast, it would build up speed. The times I have made a ship based on these technologies, the thrust appears to stay constant, instead of progressing in velocity. Or am I not seeing that aspect (if it's even implemented in game). 

In the real world these engines (referring mainly to ions et al.) have extremely low acceleration (the 5mm per second per second you mention from The Martian) but extremely high efficiency. They measure burn time not in minutes or hours but in weeks or months or even years. Because those burn times are neither feasible nor fun in KSP, the stock ion and mod engines have hugely increased thrust. To give you some numbers, the stock ion has 2000 newtons of thrust whereas the NSTAR engines that propelled the stock ions namesake Dawn to Vista and Ceres have 0.092 newtons of thrust.

It's just about amount of thrust. In KSP this means you may have to fly things a little differently since you don't have the TWR to do quick manuevers.

Edited February 13, 2016 by hoojiwana

[wasml]

6 hours ago, ComatoseJedi said:

The times I have made a ship based on these technologies, the thrust appears to stay constant, instead of progressing in velocity

To put some (more) numbers to what Hoojiwana said - That 2000m/s burn you do with a LV-T30 may take a couple minutes. With your 5mm/s acceleration its going to take a little over 100 hours. The acceleration of the Ion engine doesn't increase (ignoring the loss of mass from expended fuel) but it can keep piling on the velocity for a long, long time.