First Real Attempt at Interplanetary: Help

[Tank Buddy]

I am a very experienced KSP player an pilot, both in design and execution. I comfortably go anywhere is the Kerbin system, but I have only once tried an interplanetary trip, which ended so close to aerobreaking back on Kerbin, but failed. For some reason this prompted me to cease any attempt at interplanetary travel. In the mean time I became very proficient at other things.

Now I have decided to make a trip to Gilly (the destination of my first attempt) with an unmanned Ion lander and refueling probe. Both are very lightweight and are 2.53 tons combined. I have it currently in a 100 Km orbit and I know this: I will escape Kerbin in the opposite direction of it orbit around Kerbol, therefore I will burn on the sunny side. I will preform a mid-way plane change. I do not have any launch windows within a few months according to the launch window planner.

I was wondering what the best way to wait for the launch window is, and if it wound be more beneficial to match planes in Kerbin's orbit, if applicable. And any other general tips. Thanks.

NOTE: I WILL USE CHEMICAL ROCKETS TO GET TO GILLY ORBIT

Edited November 27, 2013 by Tank Buddy

[Smidge204]

Boy oh boy, do I have a web page for you!

http://ksp.olex.biz/

Bam. Enjoy.

Edit: If you got a long time to wait, and are already in orbit, then I suggest launching another probe/ship but leaving it on the launchpad. This will allow you to time warp without altitude limitation... might want to switch to map view, though, unless you like seizures.

Edit 2: Ninja edited!

=Smidge=

Edited November 26, 2013 by Smidge204

[Tank Buddy]

That's the website I'm looking for. Thanks.

[allmhuran]

You won't be able to match Eve's solar orbital plane while in Kerbin orbit as such, although you can adjust your escape trajectory to have a little normal or antinormal component. But this will only be worthwhile if you are leaving Kerbin at the ascending or descending node of Kerbin through Eve.

But wait! If you are leaving Kerbin at it's ascending or descending node through Eve, then that means your intercept with Eve will ALSO be at the descending or ascending node, since it happens ~180 degrees around from your current position... which means you didn't need to match Eve's orbital plane anyway!

Of course, it is actually highly unlikely that a correct phase angle with Eve will occur just as Kerbin is passing through the ascending or descending node, so all of that is irrelevant....

OR IS IT?

What if you left near (but not necessarily at) the asc/desc node but instead of burning just the right amount to get your periapsis down at Eve's orbit 180 degrees later, you instead burn just a little more so that when your new solar orbit crosses Eve's orbit it crosses at the actual ascending or descending node? It costs a little more dV to do this, but it means you don't need to perform a plane change manoeuvre. This is what I did in my tier 0 mission here (image text should of course say *periapsis* not apoapsis)

Edited November 26, 2013 by allmhuran

[Nibb31]

I wouldn't use an ion engine to land, even on low gravity bodies. It simply doesn't have enough thrust.

Also, don't use the olex.biz website, as it's all wrong. It assumes perfectly circular orbits, which is not what KSP uses. You'd be better off using MechJeb's navigation functions or the Protractor plugin (if that still works in 0.22).

[blizzy78]

Personally I've given up on launch windows. I just go out of Kerbin's sphere of influence, then create a node on my Kerbol orbit to see the closest approach markers. Drag the node around and/or fiddle with the node to get them closer together. If they are too far apart from one another, I just timewarp a complete orbit and try again. It's really simple actually.

[XiXLLAMAXiX]

Use this: http://alexmoon.github.io/ksp/

to plan your transfers. As stated by Nibb31, the olex.biz website makes some dangerous assumptions, while alexmoon's planner does not, and gives you a better idea of the effects of making/missing a transfer window

[3mon]

As stated above, the ion engine is not a good idea You wont be able to kill your speed fast enough to avoid crashing.

[Tank Buddy]

I wouldn't use an ion engine to land, even on low gravity bodies. It simply doesn't have enough thrust.

Actually, I just did the math, and on Gilly with one Ion engine I can have a lander up to 10 tones. Don't forget that the gravity is .049m/s^2, so the thrust to weight ratio is 40.8.

Trust me, I designed this mission specifically for Gilly and Gilly only.

[SpeedDaemon]

Actually, I just did the math, and on Gilly with one Ion engine I can have a lander up to 10 tones. Don't forget that the gravity is .049m/s^2, so the thrust to weight ratio is 40.8.

Trust me, I designed this mission specifically for Gilly and Gilly only.

That's fine for landing and taking off, but can you kill your speed for a capture into orbit before you whiz right though Gilly's sphere of influence?

[Tank Buddy]

Here's our gap in communication. It's my fault I didn't clarify, I intend to use conventional means to get into orbit around Gilly, then use the Ion Engines to maneuver around the surface.

Edited November 27, 2013 by Tank Buddy

[Javster]

Just use manoeuvre nodes if you aren't already.

[Vector]

Over-engineer your craft to have plenty of surplus delta-V. Allmhuran's suggestion is a good one for getting an efficient intercept (more efficient than matching planes) but once you arrive you will have to aerobrake and spend a bunch of fuel to match inclination with Gilly. Once you get the hang of things you can work on more efficient ways of getting to Gilly using judicious fly-by maneuvers, but not for your first flight.

[SRV Ron]

For long burns, about 5 minutes for the LV-N on my interplanetary ship to escape velocity, you split the burn time as usual. However, line your ship up prograde for the start of that burn and keep it pointed prograde during the burn as that marker changes. Keep an eye on the apogee in map mode during the long burn as the Delta V of the burn is going to be altered by your using the prograde marker instead of the maneuver mode one.

I also noticed an interesting greater efficiency in a intercept to Jool that was less then efficient when I made that burn while still under Kerban's SOI. Far less fuel was used then for insertion to solar orbit, then a burn to a more efficient Jool capture 42 days later. Will do some testing on those scenarios to confirm the results. Original launch of two probes will arrive at Jool SOI in 271 and 251 days. The third one that didn't go to solar orbit but was late for an ideal intercept window as it goes way past the Jool orbital plane before an intercept, is going to take one year and 178 days.

The rocket used;

The drop tanks use standard engines that are jettisoned prior to achieving orbit. The LV-N is not used for launch.

[SRV Ron]

Am keeping a log of arrival times as currently in the Career Sandbox using Nova Punch mods designs, there are three flights heading to Jool, two to Duna, and two waiting for an Eve intercept window. The Duna and Eve ones are using smaller launch vehicles.

[jduchock]

Boy oh boy, do I have a web page for you!

http://ksp.olex.biz/

Bam. Enjoy.

Edit: If you got a long time to wait, and are already in orbit, then I suggest launching another probe/ship but leaving it on the launchpad. This will allow you to time warp without altitude limitation... might want to switch to map view, though, unless you like seizures.

Edit 2: Ninja edited!

=Smidge=

whoah...new bookmark !

[SgìobairOg]

About slowing down to make orbit. I've been trying to get to Duna the last three days. I've looked up all sorts of tutorials and they all say pretty much the same thing. Leave in the right place and burn until you capture. This is what I've been doing but the Duna Periapsis is always in the millions of meters and I can never seem to change it enough to actually be able to orbit Duna. I imagine I'm going to have the same problem with any other planet. What am I missing here. How do I get close enough to aerobreak?

Also, how do I figure out if I'm leading the planet or trailing it when Quicksave doesn't appear to be working?

[Taki117]

So to change your periapsis you need to actually burn radially shortly after entering the planets SOI. This will save you lots of dV. Depending on what side of the planet your Pe is on you either need to burn Radial+ or Radial- (90 or 180 degrees) Use a maneuver node just ahead of your craft and play around with it. (Don't leave it there, just use it to figure out which way you need to go)

[Vanamonde]

If you get into the game's settings file and change the line

CONIC_PATCH_DRAW_MODE = 3

to

CONIC_PATCH_DRAW_MODE = 0

you will see your path past the planet displayed near the planet itself. Then it will be easy to place a maneuver node at the halfway point of the transit (most efficient place fuel-wise) and play with that to fine-tune the approach. Be warned, though, that entering the world's SOI while in warp can cause this path to get yanked violently from where you planned it, so be sure to drop to warp x10 or less for the SOI entry.

[SgìobairOg]

Thanks guys, launching a quick mission to deliver the kerbals that I left on the launch pad then trying again.

[quantumpion]

Personally I've given up on launch windows. I just go out of Kerbin's sphere of influence, then create a node on my Kerbol orbit to see the closest approach markers. Drag the node around and/or fiddle with the node to get them closer together. If they are too far apart from one another, I just timewarp a complete orbit and try again. It's really simple actually.

That's a huge waste of delta-V, you don't have to go heliocentric to see if you are in a launch window. You can make an escape burn maneuver node in low Kerbit orbit.

[SgìobairOg]

Made it to Duna! Thanks guys, couldn't have done it without you. I've now got my first career mode permanent base!

[Taki117]

Nice, your kerbals sure look happy too.