Solar Sails

[Fractal_UK]

I don't think that is needed. I was just tinkering a bit.Curently is the thrust still applied along the y axis and/or is it dependent on the facing in relation to the star?

The thrust is applied along the y axis (because whatever angle you are facing, the incident and reflected photon momentum cancel in all but the direction normal to the sail) but the magnitude of the force determines the force applied to the sun, maximum force is applied when the sail is perpendicular to the sun.

[The Destroyer]

So how much thrust does this produce? 0.001 Kn?

[Fractal_UK]

So how much thrust does this produce? 0.001 Kn?

It depends on distance from the sun. At Kerbin orbit, the maximum is ~ 1.31N. At Moho, it's ~ 8.75N and at Eeloo it's ~ 0.029N.

In my opinion, it's pretty useable once you get the hang of it out to maybe Duna's orbit. You can get to Jool with it by making your orbit really elliptical like I showed but you will have to aerobrake if you want to achieve orbit because once you're actually out at Jool the sail is basically useless.

[landeTLS]

Hey. Love that someone is finally attempting a solarsail. They are cool. But having the thrust decay with as much as -8kn at eeloo orbit is probably not realistic(?). Solar sails are emagined to be used for interstellar travel at a fraction of the speed of light by slow and steady acelleration. Shouldnt the thrust be a little bit more constant? I would expect it to decay some tho. I emagine it to be hardcoded into the plugin tho so i dunno.

Regarding the textures i think the animation would look way better if it was built with scaling in mind (ei. No squares but just a plain pattern. Could be based on the picture you posted of the scale model)

[SasquatchM]

Actually I have taken the tiling out to avoid the odd stretch effect when it opened

[Fractal_UK]

Hey. Love that someone is finally attempting a solarsail. They are cool. But having the thrust decay with as much as -8kn at eeloo orbit is probably not realistic(?). Solar sails are emagined to be used for interstellar travel at a fraction of the speed of light by slow and steady acelleration. Shouldnt the thrust be a little bit more constant? I would expect it to decay some tho. I emagine it to be hardcoded into the plugin tho so i dunno.

No, the thrust is indeed realistic. Solar sails aren't viable for interstellar travel unless you can actually beam power into the sail - large lasers would be suitable for this kind of task. Without that, you're largely restricted to inner system travel.

[landeTLS]

No, the thrust is indeed realistic. Solar sails aren't viable for interstellar travel unless you can actually beam power into the sail - large lasers would be suitable for this kind of task. Without that, you're largely restricted to inner system travel.

Ok. Long time since i read up on the subject:P

[Fractal_UK]

Ok. Long time since i read up on the subject:P

I mean, in theory it's possible to do this too, you could have some kind of powered sail variant where you check for line of sight to Kerbin and apply substantially more thrust from that vector to the sail - unfortunately it'd be more difficult to control because your orientation relative to Kerbin is completely not obvious much of the time.

[HoneyFox]

I mean, in theory it's possible to do this too, you could have some kind of powered sail variant where you check for line of sight to Kerbin and apply substantially more thrust from that vector to the sail - unfortunately it'd be more difficult to control because your orientation relative to Kerbin is completely not obvious much of the time.

You have plan to do beam station?

But that will take quite a lot of electricity for a powerful laser transferring such a long range...

[SasquatchM]

I think if we went with beamed power we could make a base that was capable of aiming it's lasers. plant a few of them around the planet and there you go: coverage from all angles unless your view to Kerbin is obstructed. The amount of thrust generated would vary based on how many bases are within your LOS. It would be pretty awesome setting up a laser base with power supply on another planet as a mission though.

[wasmic]

Woooo, you're back! I really loved your old mods, sadly they didn't get a lot of exposure. This looks great, though.

[SasquatchM]

I did not want to imply that we had even discussed beamed power, so don't get all excited for it as I have no idea, code-wise, how possible that would be.

[Fractal_UK]

I did not want to imply that we had even discussed beamed power, so don't get all excited for it as I have no idea, code-wise, how possible that would be.

It's potentially doable, I have plenty of code in Interstellar that could be adapted to do it - you could have laser parts powered by nuclear reactors or whatever to beam power to your sails. The microwave transmitter code could be adapted to it.

Of course this then becomes more a case of me acquiring your model for my mod than me helping you make a basic plugin, which may not be exactly what you had in mind! So it depends where you want to go with it and whether you want it to be a small plugin with a simple part or something that becomes part of a more involved set of infrastructure to use it, or, of course, both is also an option.

[SasquatchM]

Fine with me. I mainly make parts that I want to play with anyway.

I have been thinking about a laser emitter base ever since it was mentioned.

[frizzank]

For simplicity sake it may be easier to have a beam that points from the spacecraft to kerbin (Solar panels do this with the sun already). It will look like its coming from kerbin but as long as it comes on and off instantly no one will know.

[SasquatchM]

we could get away with it pointing in just the general direction, it's not like anyone is going to follow it the whole way, even if it would be visible out of atmosphere at all

[Fractal_UK]

we could get away with it pointing in just the general direction, it's not like anyone is going to follow it the whole way, even if it would be visible out of atmosphere at all

It would illuminate the sail so I could maybe have it light up the appropriate face? Then you'd be able to see the laser light reflected off the sail but yeah, there would certainly not be a visible "beam" in space, that is caused by the laser scattering off molecules or small particles suspended in the atmosphere.

[SasquatchM]

Remote Laser Emitter bases on atmosphere-less bodies would have considerably less loss of power en-route to the sail as well.

[SasquatchM]

[skykooler]

That looks beautiful!

[landeTLS]

I agree. Its a very nice model

[SasquatchM]

Release will be coming from here: KSP Interstellar

[RiggerLee]

So what's the story on this? I don't see it mentioned in the Interstellar Mod. Is there any interest or intent in going forwards with it?

And I don't quite follow the discussion of how you plan to implement it. You talk about the thrust being perpendicular to the sail which is fine but how will you vary it in relation to the angle of the sail. I was trying to scratch it out on an envelope and came up with the force being in relation to 2*S*(cos(a)^2) S surface area, and a the angle to the light source. I also don't understand the problems with control. It seems like the flight computer in the Remotetec mod does a good job of flying it relative to the orbit or a set vector. I would think that you could also set a thrust vector in the same way relative to the orbit or node and then look at the efficiency of the sail. I'm not sure if I'm doing it right but it seems to drop off very quickly as you try to vector it away from the line of the light source. You could make it much more versatile with alternate sources. I love the idea of remote lasers that could push these things around the system. You would still have the force vector from the sun which might actually be fighting you but that would make it fun. By turning on and off different lasers in addition to the Sun I think it could be a workable system for small probes. The math doesn't seem that hard I just wish that I was enough of a geek to write code.

I would just like to encourage you to keep working on it. I for one would love to see various sizes of sail and lazier stations to do missions with.

Lee