InterPlanetary

[Qumefox]

when using protractor, make sure you have 'adjust' enabled, so your angles are adjusted for your ship's TWR. Also try to design your ship so you won't have to stage in the middle of a transfer orbit burn.

What I do on interplanetary transfers (from circular kerbin orbit) using protractor is timewarp until the phase and relative phase angles of your target are (relatively) matched, then start a 100% burn when the orbit ejection angle matches the listed one for your target. Then keep burning until the listed required delta-v change for that target hits 0m/s. If you're looking in map mode, this should result in, at least looking top down, your orbit intersecting that of your target. If you're lucky, your target is already close enough to kerbin's inclination at that intersection to get an intercept. If not, you need to wait until you're halfway to your target to do an inclination adjust burn. Then it's just a matter of pushing your orbit up.. or down, whichever matches your target, until you get an intercept.

[Rickenbacker]

...and right after I wrote that, I DID make it to Duna . Didn't have the latest version of Protractor, so it wasn't adjusting for my rocket's thrust. Poor Steve Kerman won't be getting home, though, but at least he's got a great view!

[dan548198]

I am having the same problem getting to Eve! I am using the Interplanetary Travel Calculator to get the right angles etc. It easily works for reaching the outer planets, but not Eve or Moho. I always end up with an outward-expanding orbit, towards Duna.

Thinking about it, I'm not sure how this method can work for the inner planets. As soon as your orbit goes out of Kerbin you enter a Kerbin-like orbit around Kerbol. Continuing to fire prograde is just going to expand your orbit out further. Turning around and firing retrograde is inefficient and just ends up bringing you back to Kerbin. What am I doing wrong?!

[Vanamonde]

As soon as your orbit goes out of Kerbin you enter a Kerbin-like orbit around Kerbol.

That's true of outward-bound flights as well, so it shouldn't make a difference.

I always end up with an outward-expanding orbit

Have you noticed that the calculator gives ejection angles clockwise for outer planets and counter-clockwise for inner planets? Might that be part of the problem?

Continuing to fire prograde is just going to expand your orbit out further.

Don't forget that perspective changes as you go from one SOI to another. Start a burn over the dawn side of Kerbin and you will be thrusting prograde relative to Kerbin, but retrograde relative to Kerbol. You're actually firing Kerbin-orbit-retrograde the whole time.

I too am having great difficulty reaching Moho, but I suspect that a large part of the problem is that the equations have to assume that your burn is instantaneous, which of course it can't be.

Edited October 18, 2012 by Vanamonde

[TheHengeProphet]

I believe Moho is perhaps the most difficult planet to reach, as you have a considerable velocity to kill to achieve Moho orbit, with no option of aerocapture. Landing is even worse, as the heat at lower altitudes is enough to detonate your fuel tanks!

For those of you who don't like your inclination when you're heading into a SoI, I personally adjust it when I am around 11 days out. This allows me to achieve whatever angle of orbit I desire and gives me a good line of sight for adjusting for aerocapture (or aerobraking, and landing, if I'm feeling particularly ballsy).

[OxfordTheCat]

Thanks for that.....

... my first interplanetary mission, a mission to Duna, met an abrupt end just as I was about to start my descent.

I couldn't figure out what happened but all of a sudden I was short an engine.

[Tauge]

Thanks for that.....

... my first interplanetary mission, a mission to Duna, met an abrupt end just as I was about to start my descent.

I couldn't figure out what happened but all of a sudden I was short an engine.

Did you happen to change your time compression suddenly? From say, very high to x1? Either way, it sounds like what has been dubbed Space Cthulhu. It's bug that cropped up in this build, there is a fix in the next patch, which will be ready Soonâ„¢.

[SNapple]

I just wing it.

[Tauge]

I just wing it.

Kif: Sir, this is a leisure cruise. Our path was set by the travel agency.

[He presses a button and a map comes down on the wall showing the route is a straight line from Earth to another planet.]

Zapp: That's for schoolgirls! Now here's a route with some chest hair.

[He squiggles a new course onto the map.]

Kif: But that course leads directly through a swarm of comets.

Zapp: Yes, comets! The icebergs of the sky. By jack-knifing from one to the next at breakneck speed we might just get some kind of gravity boost ... or something. [Kif sighs.] It's time to shove a jalapeño up this ships tailpipe. [He grabs the wheel.] Divert power from the shields, full speed ahead!

[SNapple]

I just wing it.

Kif: Sir, this is a leisure cruise. Our path was set by the travel agency.

[He presses a button and a map comes down on the wall showing the route is a straight line from Earth to another planet.]

Zapp: That's for schoolgirls! Now here's a route with some chest hair.

[He squiggles a new course onto the map.]

Kif: But that course leads directly through a swarm of comets.

Zapp: Yes, comets! The icebergs of the sky. By jack-knifing from one to the next at breakneck speed we might just get some kind of gravity boost ... or something. [Kif sighs.] It's time to shove a jalapeño up this ships tailpipe. [He grabs the wheel.] Divert power from the shields, full speed ahead!

Let's be honest, this forum is full of Futurama references. We need to groove it up in here.

I'm a smart.

There we go.

[Trekkin]

Does anyone actually use more than one nuclear engine/lv-909 for interplanetary flight? I used to, and now I don't, but I'm wondering if there are interplanetary flight paths that need more than negligable acceleration.

[OxfordTheCat]

I do, depending on my design, but only because I come in on landings way too hot and need the extra thrust to slow down in time:

I don't use parachutes except on the return to Kerbin, so I usually have two or three engines at full blast for a hundred thousand feet or so to slow down on my hybrid transfer / lander stage.

(I'm a relatively new rocket scientist, so my approach trends more towards Wile E. Coyote than Werner Von Braun....)

If I'm using a smaller lander and a dedicated transfer stage, then I'll usually only have 1 to conserve fuel, with the extra engines on the lander still.