Best way to get close to the sun?

[Trekintosh]

I know the Oberth effect makes it easier to get out of Kerbin's SoI, but if I want to get close to the sun, would it be easier to burn on Kerbin's retrograde instead of prograde? Or would that not make any significant difference? Also, is there an easier way to get to the sun once out of Kerbin's SoI besides burning retrograde? Like would it be more efficient to swing by Eve and maybe Moho from there? I'm trying to get a solar power satellite into low orbit with Interstellar Mod parts.

[Specialist290]

Welcome to the forums!

For the first part: Yes, for travel to the inner system, you want to burn so that you're heading retrograde relative to Kerbin's orbit around the sun. That will slow you down relative to the sun, putting you into a lower orbit.

Gravity assists to get closer to the sun should be fully possible; it's really just a matter of timing and positioning on those. You might find this guide to be helpful in that area.

Hope this helps!

[Vanamonde]

Moho would be difficult to use for a slingshot, though, as matching orbital inclinations for an intercept would add a lot of delta-V back onto whatever you were picking up from the planet.

[Specialist290]

Agreed there; forgot to mention that Moho is slightly less-than-ideal for that sort of thing. Eve's large Sphere of Influence and surface gravity, as well as the fact that it's relatively easy to reach from Kerbin, should make setting up a gravity assist fairly easy, however.

[Deathsoul097]

TBH, I think you might want to try and go up first, depending on how low you want to go. If your Apoapsis is higher, then it will take less Delta V to lower the Periapsis, Although it will take quite a bit more than what you are used to to get into the desired orbit.

[bsalis]

TBH, I think you might want to try and go up first, depending on how low you want to go.

Yes - a Bi-elliptic transfer...

http://en.wikipedia.org/wiki/Bi-elliptic_transfer

You might want to play around with some maneuver nodes and see what you get delta-V wise.

[Kasuha]

The closest I got to the Sun was when I was returning from Dres and decided to take a shortcut. Lowering my periapsis from Kerbin level to about half Moho level cost me just about 1000 m/s.

So the most comfortable way near the sun might be taking a detour on the way home from upper planets.

Edited October 30, 2013 by Kasuha

[blizzy78]

I know the Oberth effect makes it easier to get out of Kerbin's SoI, but if I want to get close to the sun, would it be easier to burn on Kerbin's retrograde instead of prograde?

Just to point this out since I didn't see anyone do it yet: The things you mentioned have nothing to do with each other. Regardless of you going into Kerbin's prograde or retrograde, the Oberth effect always applies.

[Trekintosh]

Thanks for all the suggestions, guys. I've had to redesign my power satellite slightly, so I can't try it right now, but I will report back once it is done. Currently I'm planning on catching an approaching Eve transfer window for maximum efficiency. To get the most out of it, would I want to intercept Eve on a retrograde orbit? In my mind that might help me go somewhat lower than a "normal" Eve orbit.

Just to point this out since I didn't see anyone do it yet: The things you mentioned have nothing to do with each other. Regardless of you going into Kerbin's prograde or retrograde, the Oberth effect always applies.

Well it barely applies in that I am gaining a slight boost from Kerbin's orbital velocity, but really you're right.

[SunJumper]

AFAIK, it takes more dv to go straight to the sun via an oberth burn than to boost the solar apoapsis via an oberth burn and descend from the higher altitude. Boosting the apoapsis to about Jool's height results in a delta-v of about 4km/s. Clearly, this is more if you want to return to Kerbin (but not much more if you aerocapture and are patient)

[SRV Ron]

Just to point this out since I didn't see anyone do it yet: The things you mentioned have nothing to do with each other. Regardless of you going into Kerbin's prograde or retrograde, the Oberth effect always applies.

A burn using the Oberth effect around Kerban will point to the Sun, but end up on a retrograde escape.

To reach close Sun fly by will take a ton of delta V, much more then doing a Voyager mission. There should be a substantial fuel savings if one can do an Eve encounter that slows you down retrograde without ending up with a capture. You can use aerobraking to aid in the slowdown but the maneuver will be tricky.

To get into a close circular orbit will take tons more fuel. Note the speed on this suicide encounter.

[WeirdCulture]

I had (serval) provbes with a ion drive 8 1x6 and the whole empty surface covered with solar modules and a huge pack of xenon gas.... and a lot of time... these were 4-5 hour burns

[Gigiwal]

Probably the best way to get to low space in the sun is to do a hohman transfer orbit to eve, just make sure that you come in an eastward orbit, then when you're low enough burn prograde and if you did it right you can combine the oberth effect with an eve gravity assist to get you much closer to the sun with less fuel.

[Gigiwal]

Correction: Go in a westward orbit or retrograde

[DeMatt]

Probably the best way to get to low space in the sun is to do a hohman transfer orbit to eve, just make sure that you come in an eastward orbit, then when you're low enough burn prograde and if you did it right you can combine the oberth effect with an eve gravity assist to get you much closer to the sun with less fuel.

That's very nice, but I'm confident that Trekintosh solved his problem a long time ago - given that the most recent post in this thread, barring your own, was almost two years ago.

Correction: Go in a westward orbit or retrograde

And of course, you can edit your own posts by clicking the "Edit Post" button to the lower-right of the post in question.

[Claw]

I appreciate the attempts to help, but this thread is a year and a half old. I would guess that the user has either figured it out by now, or quit trying.

Cheers,

~Claw