[Tutorial] Interactive Illustrated Interplanetary Guide and Calculator

[zapy97]

just a suggestion you could use the sun and have instead of the kerbin orbit code it to be changeable to the sun the use that to make the orbit modulator thingey

[JackAz]

Wow, this is going to help many people, especially new players such as me.

Great work, keep it up.

[jhz3]

This is amazing. Time to practice my Duna transfer burns. Is there a way I can calculate delta V needed? I'm assuming it'd be (initial dV+(velocity at time of transfer-dV used during burn)) for the outbound leg, am I close?

[Rascal Nag]

This is quite an impressive calculator, definitely will be using this. All that would be needed to make this perfect would be a way to calculate paths using gravity assists, for voyager-like missions.

[olex]

This is amazing. Time to practice my Duna transfer burns. Is there a way I can calculate delta V needed? I'm assuming it'd be (initial dV+(velocity at time of transfer-dV used during burn)) for the outbound leg, am I close?

For the transfer burn, the needed dV is (ejection velocity - parking orbit velocity). I'll add a dV display to the calc.

[Ciechosz]

I'm trying to calculate transfer from Mun to Minums, but the calculator doesn't work with parking orbit set to more than 637.

[olex]

Updated with actual 0.17 data - have fun flying to new planets!

[billyzero]

Great tool but I need some help. I think I understand the steps I'm supposed to take to intercept the planets but how do I know when the two planets are at the right Phase angel and how do I know when my ship is at the right ejection angel? I am assuming the ejection velocity is just the "speedometer."

In other words, is there somewhere I can look where I can get a readout on when Kerbin (the planet, not the sun) and Eve are at the -54.13 degrees for phase angel and when my ship is at the 154.58 degrees ejection angel? I'm just eye-balling it right now adn it's not going very well.

[olex]

Right now, there aren't any tools built into the game or plugins (to my knowledge) that will help you measure those angles. What you can do is take inspiration from the images generated by the calculator, and use either a protractor (holding it against the screen) or a tool simulating one (google "mb-ruler" for the one I currently use).

[GalaxyGryphon]

im not going to lie i tried this calculator about 5 times using a protractor every time (an on screen, accurate one) and ive missed the planet for millions of miles every time.

it would be nice if you can upload a youtube video to prove it actually works accurately.

(no offense, im not saying it doesn't)

[NovaSilisko]

One thing I've noticed is that the calculator doesn't take into account orbital eccentricity, you can reach the correct point for a transfer, but due to the planet's eccentricity, it will appear to be way off.

[bsalis]

I think people need to figure out the eccentricity part themselves.

What I want to know is if the ejection angle is correct for moon-to-moon transfers. Since my understanding is that the formulas provided by Kosmo-not assumed that the ejection trajectory is hyperbolic. Which may not always be the case.

[phoenix_ca]

Oh dear...you know...I'm going to shamelessly use MechJeb for interplanetary transfers.

It's not that I don't love math. It's that I don't necessarily want it to get in the way of the hilarity of splattering Kerbals on the side of the new planets.

[togfox]

Until mj is updated im afraid math is your only option.

[Moach]

Make sure you're not starting the burn at the ejection angle itself... I reckon no calculator could ever predict what form of monstrocity you're launching off that burn, and how fast it can accelerate (thus affecting the antecipation required to start the burn, since you'll cover some ground before building up the needed velocity)

And still, you should ideally end up precisely at a periapsis of the height defined in the calculator when you reach that velocity target.... That's some very fine flying it requires, so make sure to have a decent RCS setup aboard... But don't worry if you dont get it perfect, its not like its rocket sci.... Oh wait...

As for the alignment burn, MJ already has support for this, but you have to be in the same parent SoI as your destination (gotta be in solar orbit) before you see the option to target any of the other planets for rendezvous

You can also check your plane alignment on map view, this is not difficult, simply line up the view so the target orbit appears as a single straight line, i.e. parallel to the orbital plane - then try to find the point where your own orbit crosses it - this is your ascending/descending node depending on whether youre crossing up or down, so point north or south on the ADI (north to swing your orbit up ahead of you, south to bring it down), then just burn until the two orbits are parallel enough to get an intersection

I have yet to try the onscreen ruler, seems very much clever and by far more precise than my current solution of holding a physical protractor up and eyeballing stuff through it (it's clear plastic)

But then, i went to fire up my rig today, heard a pop, nothing came "on" and the psu smells funny.... Goddamn thing just exploded on me right when i need it so bad, so i got some replacement to do before anything else....

Edited September 21, 2012 by Moach

[MaxMurder]

Amazing work! This is incredibly helpful and i haven't even tried using it in practice yet. I now have a good rule of thumb to go by as far as phase angles go. My first duna mission took 4 years to reach the planet. Now ill probably be able to do it in less than a month!

[Shedao]

Ok, 0.17 is there and the interplanetary rocket ready for its one-way trip to Duna. Unfortunately I'm experiencing some trouble when using this calculator.

Setting warp to 100000 I wait until Duna is 44° ahead of Kerbin. Once this is achieved I wait again until my craft reaches the right point on its orbit around Kerbin and set the thrust to maximum. Now the problem: The calculator says (going from a 100km parking orbit) I need about 3289m/s but then my orbit would nearly reaching Jool

Am I thinking wrong? 3289m/s is the orbiting speed around Kerbin right? Or should I wait until my craft swithces the SOI from Kerbin to Kerbol and then reach 3289m/s?

[Motorsheep]

Nah, if you wait for the SOI switch, it will give you your Sol orbiting speed, which will be around 9km/s. So the figure you're using should be right.

I've never used the figure though. Just did it like with orbital rendezvous - burn until your apoapsis is about the same as Duna's orbital radius. If the trajectory prediction doesn't turn out a Duna encounter, then you mis-timed your burn.

So far, I haven't managed to get into another planet's SOI. I find it incredibly hard to eyeball the angles, and I don't have a protractor at hand...

also, you might just be orbiting Kerbin in the wrong direction.

Edited September 21, 2012 by Motorsheep

[olex]

If the trajectory prediction doesn't turn out a Duna encounter, then you mis-timed your burn.

That is not always entirely correct. Getting a straight intercept using the calculator data takes quite some luck, since the planets are all in slightly eccentric and slightly inclined orbits, and the calculator doesn't account for that.

What you need to do if you don't get a straight intercept, is warp until mid-transfer, and then first burn to adjust your transfer inclination to meet with the target orbit, and then possibly do a couple burns to offset the phase angle error introduced by eccentricity. To do that, you need to judge whether you are "too early" or "too late" at the transfer point (a quicksave and warping to rendezvous point is a good way to determine that). If you are early, burn between RAD+ and retrograde to shorten your orbit while still keeping it near the target, and if you're late, burn between RAD- and prograde - with those corrections, if the inclination is correct, you'll definitely get a rendezvous (as long as you have enough fuel for the correction burns).

[phoenix_ca]

So...what do I do if I want to just get going and use a different phase angle?

[zarniw00p]

In my experience its much easier if you do the transfer burn at a phase angle a bit smaller than the calculator recommends (e.g. 40 instead of 44 degrees for Duna). You can always push up your apoapsis a little bit and wait for the planet to catch up to you.

Btw, are there any chances that we will get planet -> moon calculations soon?

[Pingonaut]

Very useful tool, I'll be using it for my missions. Thanks!!

[OrtwinS]

This must become a plugin.

This calculater plus a simple display for the current phase angle between origin and destination and the ejection angle.

I do not want an auto-pilot that does the actual control for me, just a more complete set of instruments.

Damned Jim. I'm a Doc.. eh.. nano physicist! not a programmer!

Anyone willing to take on the challange?

[Awaras]

So far, I haven't managed to get into another planet's SOI. I find it incredibly hard to eyeball the angles, and I don't have a protractor at hand..

also, you might just be orbiting Kerbin in the wrong direction.

I've been using this on-screen protractor and it works great:

http://www.chip.de/downloads/MB-Ruler_16688396.html

The only downside is that you need to run KSP in windowed mode. You center the map camera on the sun and place the center of the protractor in the middle of the sun. Then you can rotate the protractor and measure any angle you need.

Before i found it, I used an android app called 'Max Protractor' that lets you take a photo of your monitor and then measure angles on that photo.

[DakotaSpace]

How do I know where my ship is in relation to these angles while in parking orbit? Is it impossible to just eyeball now? I'm trying to reach Duna but I'm sat at max time acceleration just waiting for an encounter...