How accurate are in-game solar panels?

[UmbralRaptor]

Wouldn't work. We have no way of knowing how much power in the ion engine comes from burning the fuel.

Ion engines don't 'burn' their propellant. They ionize it, and then accelerate it through electrical and/or magnetic systems, depending on the thruster. All of the energy the propellant gains is external. Especially since the current stock ion engines have a Xenon-like propellant.

[azazel1024]

Yes and no also. We could scale it up based on current ion engine techologies. However, there is more than one way to ionize and accelerate and ion. Even with Xenon. The Isp and thrust are based on not just the fuel source (Xenon in this case) and how much energy is put in to the fuel, but also how the molecules/atoms are ionized/de-ionized and accelerated.

VASMIR is more efficient (thrust and Isp) per watt than current ion drives IIRC.

[magnemoe]

In the name of science let's do it!

The KSP's PB-Ion Electric Propulsion System gives 4200s of Isp and consumes (correct me if wrong) 14.442E/s (or Z/s if you like) for 500N of thrust.

NEXT ion thruster has 4190s Isp, drawing 6.9kW for 0.236N of thrust.

In other words, if we tape 2128 NEXT thrusters together we get about the same thrust as one Kerbal B-Ion engine. All that NEXT will draw 14.683 megawatt of power.

Assuming NEXT and PB-Ion are roughly equal in efficiency (clearly a shaky assumption, given the incredible TWR of a Kerbal ion engine) we know 14.442E = 14.683MW, or E = 1.02MW.

What does this mean?

• a Giganator panel generates a maximum of more than 18MW of electricity, that's 64,800MWh per hour! The entire US generates only a bit over 1000GW, so about 60 Giganators at full power can power the entire US.
  
• a Z-500 battery holds about 34.62MWh of energy, or 124,632MJ, or about 30 ton of TNT in a 50kg package - an energy density impossible to achieve without going nuclear
  

Conclusion: KSP ion engine is OP

ION engines are not an good example, in real world ion engines have week long burns, this does not work in KSP so they has to accelerate an probe reasonable well while being weak enough to not be exploitable.

[architeuthis]

Regarding the inverse square law, I hope KSP is amended to reflect reality in this case. As things stand it is difficult to justify using RTGs for anything but surface missions on a power to weight ratio. On account of the 'tyranny of the rocket equation', we would otherwise be forced to heavily optimize mass for missions to the outer planets. If we make assumptions such that the solar panels are always facing Kerbol, and are never occluded then is seems that OX-B solar arrays out preform RTG by at least a factor of 5 at Jool's distance (if I understand correctly currently insolation at Jool is half of Kerbin, scaling linearly between).

In reality we would have something more along these lines:

Edited May 6, 2013 by architeuthis

[EatVacuum]

On ‎25‎/‎04‎/‎2013 at 11:58 AM, That guy who builds stuff said:

Wouldn't work. We have no way of knowing how much power in the ion engine comes from burning the fuel.

Yes, we do. None of the power in ion engines comes from burning the fuel. The fuel is almost always an inert gas and it is accelerated using either electrostatic or electromagnetic force and leaves the engine at ridiculously high speed. Very efficient in terms of fuel expended for delta V gained, but due to the harsh reality of physics, you need a lot of electrical energy to accelerate a miniscule amount of fuel, so the thrust is very low compared to chemically powered rockets.

 

[Snark]

This is an ancient thread, over three years old.  Much of the content is now irrelevant due to changes in the game over the last few years.

Locking the thread to prevent further confusion.  If you'd like to discuss any of the topics mentioned herein, please start a new thread.