Interplanetary Travel Planning - STOCK

[roosterr]

I do not want to double dip the forums, and searched to see if my question was already answered and came up with way too many results. So if I am asking a question that has been answered too many times already, please point me to an existing post that may help me, if you know of one.

So here is my question: I have traveled only to Duna and Ike, aside from the Kerbin system. I did so using the Protractor Mod, and do know how to use it to visit other planets. I also figured out how to travel to Duna WITHOUT Protactor, but only from remembering how the approximate line-up should look. I am ready for another interplanetary journey to somewhere other than Duna and would like to learn how to do it without the aid of a mod, aka STOCK.

I tried using maneuver nodes, but it is really just taking stabs in the dark and has failed, and there is no skill in that any way.

SO, HOW DO YOU DO IT STOCK?

Scientific calculator, math? I hope not (even though I may be willing to learn).

Edited September 26, 2013 by roosterr

[regex]

How I got to Eeloo stock:

• Load up on delta-V. If you think you need more, add double the extra you think you'll need.
  
• You'll be eyeballing the ejection and phase angles, but it's not that hard to be roughly precise.
  
• It is beneficial to use an external tool to find the optimal launch window you'll need.
  
• If you don't want to use an external tool, the maths are all available on the internet and the Wiki should provide all the planetary statistics (I think).
  
• Don't bother with non-optimal launch windows, they'll be tough to find and take a lot more delta-V than listed.
  
• Create the maneuver node so you hit it on the next pass around Kerbin (right behind your ship), that will give you more time to mess with it.

[Captain Sierra]

To make the math easy, use this website to calculate the rough dV, the ejection angle, and the phase angle for transfer. That should help a lot.

[roosterr]

I should have enough dV, I am only sending small probes and have a beefy lifter ready. I have stacked a tiny ion SEP vehicle onto a NERVA booster, atop my heavy lifter. Should be plenty of dV, at least I know it is a lot more than needed to get to Duna from past experience. BUT, I dont even know how to calculate dV from STOCK, so that is another question in itself. Overall I am a competent builder and pay lots of attention to ISP etc. So ejection and phase angles are my question. Regex, are you suggesting I mostly wing it with maneuver nodes if I go stock? I am trying to avoid that, but maybe I gave up too soon.

[roosterr]

To make the math easy, use this website to calculate the rough dV, the ejection angle, and the phase angle for transfer. That should help a lot.

Ah! yes, I remember seeing this site before (before I got Protractor way back, LOL) I think that is what the doctor ordered, something between winging it and doing math.

[regex]

Regex, are you suggesting I mostly wing it with maneuver nodes if I go stock? I am trying to avoid that, but maybe I gave up too soon.

The only tools stock KSP gives you for interplanetary travel is the map view and maneuver nodes, so, yeah, I am telling you to "wing it". But I'm also suggesting you use external tools as suggested by Captain Sierra.

[roosterr]

YES, after reading into the page, this ===>> http://ksp.olex.biz/ is perfect. Just nerdy enough, but not painful math, and I get to keep my rocket stock. AND it is a great intro to getting started on the math in the future which is an interest. I am marking as answered. Thanks Sierra, you too regex.

[roosterr]

The only tools stock KSP gives you for interplanetary travel is the map view and maneuver nodes, so, yeah, I am telling you to "wing it". But I'm also suggesting you use external tools as suggested by Captain Sierra.

Hopefully the dev team will include a stat panel giving us the numbers in the future so we dont have to wing it. Even if we have to do the math, we need some numbers to derive solutions, such as Dx, oribtal speeds, or whatever is needed to make the math happened. I am guessing that interactive page was created from KOSMO-NOT trial and error experiences, which is great for now.

[SRV Ron]

Get into solar orbit as circular as possible. Launch at dawn to direct escape velocity for visiting the outer planets and at dusk for the inner ones. Just keep in mind that you may have to wait a Kerbal year or two in order to get an efficient intercept window using the Add Maneuver tool. Do so using probes. Place several of them closely spaced apart send each on their way as the launch window becomes available. Keep track of them in a notebook. However, while waiting for launch windows, you can plan and launch other missions until those launch windows become available. Once they get near, launch your manned missions.

Don't forget to place idle craft so that their solar panels are getting direct sun regardless of where they will be in solar orbit, Otherwise, you may find dead batteries at the time you need to conduct the intercept maneuver.

[Caesar15]

You guys actually use math for ksp? Man if I tried using math...

[Captain Sierra]

Hopefully the dev team will include a stat panel giving us the numbers in the future so we dont have to wing it. Even if we have to do the math, we need some numbers to derive solutions, such as Dx, oribtal speeds, or whatever is needed to make the math happened. I am guessing that interactive page was created from KOSMO-NOT trial and error experiences, which is great for now.

That site is actually operating on the same complex math you would use if you have the numbers. It has the orbital parameters and speeds (for circular orbits) so it can determine orbital velocity based on body and altitude. The website just makes the math visual. Glad I could help.

[WhiteWeasel]

Get into solar orbit as circular as possible. Launch at dawn to direct escape velocity for visiting the outer planets and at dusk for the inner ones. Just keep in mind that you may have to wait a Kerbal year or two in order to get an efficient intercept window using the Add Maneuver tool. Do so using probes. Place several of them closely spaced apart send each on their way as the launch window becomes available. Keep track of them in a notebook. However, while waiting for launch windows, you can plan and launch other missions until those launch windows become available. Once they get near, launch your manned missions.

Don't forget to place idle craft so that their solar panels are getting direct sun regardless of where they will be in solar orbit, Otherwise, you may find dead batteries at the time you need to conduct the intercept maneuver.

I thought you weren't supposed to circularize in solar orbit, that it wastes too much Dv?

[regex]

I thought you weren't supposed to circularize in solar orbit, that it wastes too much Dv?

As I understand it, it's horribly inefficient. Much better to do a direct Hohmann transfer from the orbited body because you take advantage of the Oberth Effect.

[roosterr]

That site is actually operating on the same complex math you would use if you have the numbers. It has the orbital parameters and speeds (for circular orbits) so it can determine orbital velocity based on body and altitude. The website just makes the math visual. Glad I could help.

I get that, but where did they get the original numbers to plug into the math? My guess is that they would need to start with AT LEAST A distance and orbital velocity of the target body to use for their calculations.

Edited September 26, 2013 by roosterr

[regex]

I get that, but where did they get the original numbers to plug into the math? My guess is that they would need to start with AT LEAST A distance and orbital velocity of the target body to use for their calculations.

Map view has some information and so does the Wiki. Of course, if I had none of that I'd use the mod feature to poop out some values into the log. Failing that, well, you can always explore assets in Unity.

[roosterr]

Map view has some information and so does the Wiki. Of course, if I had none of that I'd use the mod feature to poop out some values into the log. Failing that, well, you can always explore assets in Unity.

Good enough regex, thanks. I think I am going to rank up to rocket science 102 here this winter and start learning the math. But for now, I think I'll be heading to Jool this weekend for my first run using the olex calculator. Last check, it looks like my planets are aligning to do so and I see a window.

[roosterr]

.....I'd use the mod feature to poop out some values into the log. Failing that, well, you can always explore assets in Unity.

Uuuhhuhhuhh,huh,huh, you said poop, and log, uhhhhhuhhhuuuuhh.

[Kasuha]

I did a successful no-math "brute force" stock-only mission to Eeloo just a few days ago.

My ship was a multipart one, it consisted of command module (command pod and monopropellant fuel tank), engine module (medium fuel tank with six LV-N engines and landing legs), and five fuel modules consisting of a monopropellant fuel tank and orange fuel tank. They all were assembled in orbit and connected using docking ports (the large ones), each module except the command module had one docking port on each end, command module had just one.

Every time I ran out of fuel in one of fuel tanks I "rebuilt" the ship, disconnected the empty fuel tank and continued the journey without it. When I got to Eeloo I still had two tanks.

Travel to Eeloo was a "classical" one - get in Kerbol orbit, match inclination, plan a maneuver to get close (which accidentally fell to the farthest point on Eeloo's orbit), get into Eeloo SOI, brake to circular orbit, detach the lander and land. I left remaining fuel tanks in orbit and connected to them on return.

Travel back was faster - I got out of Eeloo SOI in "Eeloo retrograde" direction, then planned my maneuver carefully to get right into the Kerbin SOI, without inclination matching. It can be done if you're pulling the maneuver nodes carefully enough to intersect and then not deviate from the orbit and move the intersection around the orbit till you find close enough encounter.

So yeah, it is possible without mods. But of course, mods allow you to do it more effectively.

[Monkeh]

Get into solar orbit.

Click on target body and make it your target.

Note where the ascending and descending nodes are.

Add maneuver node near one of them.

Drag Prograde marker until it intersects the orbit you want.

Look for the 'target position at closest approach' and 'closest approach' markers.

Play with delta v and exact position of maneuver node until the encounter marker appears.

Carry on tweaking until the distance between encounter and escape is the largest you can make it.

To align with different inclinations get to either the ascending node or descending node, (ie on the same vertical plane), add a maneuver, align the map camera so your target's orbit is a single green line and use the pink thingys on the maneuver node to line up your projected orbit with the thin green line before you start your long burn.

[Radiokopf]

Wanna go in: Burn prograde when between Kerbin and Sun. (applies for returns from moons too)

Wanna go out: Burn prograde when on the other side.

or Slightly before.

Make the intercept (or closing) brun from LKO, for heavy crafts you maybe have to make it some more parts. Burn to a highly elliptical orbit and do the rest the next time you go around.

1. Intercept burn

2. inclination brun

3. Close approch burn (brun north, then east, then down if you dont use the node. Or the opposites )

for the alignment: its takes some time but you will know where eg. Duna has to be. You could just leave a probe in orbit to check where jool would be, is you dont wanna use any help

[SRV Ron]

I thought you weren't supposed to circularize in solar orbit, that it wastes too much Dv?

What I mean by circularize as much as possible is doing so by shutting down the instant you hit Kerbal escape velocity. Doing so afterwards is just wasting fuel. Having to do the transfer burn from the Apoapsis also takes more fuel.

Launching sunrise or sunset to Kerban escape gets you to the most efficient solar orbit for the transfer you are planning. Launching at any other time will increase the fuel use for the later transfer since you lose the boost you would get from Kerbal rotation.

Anyhow, this link explains the transfer process in detail;

http://forum.kerbalspaceprogram.com/threads/27236-Tutorial-Step-by-step-Interplanetary-Hohmann-transfer-guide-and-tips

Some ships that I have built will reach anywhere in the Kerban system;

All stock using an LV-N with drop tanks.

Another less efficient stock design, but no half hour burns required;

At Moho orbit

Eeloo using a launcher with Nova Punch parts.