Long Mission Pre-Planning

[FlyMario]

Ok, I have launched into space and landed on the mun... Wasn't terribly complicated. Just wait for the moon to come up on the horizon and fire till you are influenced by it... then retro when you get there to form and orbit.

I landed on minmus by playing with the Mission Planner. And Duna... well that was what I hoped for... but no idea how to make a real plan. I know I burned up a ton of fuel not needed. So my guy is stuck there.

What I find fascinating and would love to understand is how people would plan a big mission before they even launch. Curve around the sun to gain speed... use jupiter to sling you around this orbit and then finally land on the planet you desire.

There must be a way. I want to adventure to all the planets for sure but would look a lot more prepared!

Any of you have stories or advice I can use to accomplish this. Is this going way overboard?

Thanks,

FlyMario

[Noticeably FAT]

About the only planning I do is using this calculator to find the needed phase/ejection angles and approximate dV, then I use MechJeb to figure out my current phase/ejection angles and approximate current dV (there are other mods that will give you the same info, I just like MJ). Then I just play with the maneuver nodes to get an intercept. Beyond that it's all trial and error. Lots and lots of trial, and even more error.

[astropapi1]

Here's my technique: Launch your rocket into orbit, time-warp the hell out of it until you're on a launch window, Fire up your rockets, Profit.

Nah, just kidding. I go through some planning, testing things on kerbin before finding out something doesn't work when I'm on my way to duna, preparing mentally for the challenge, and fixing little things that would ruin the mission (like upside-down lights or ladders). I've never done gravity assists. The odds of getting one accidentally are really low, and I'm not such a planner... I just do things.

[Amaroq]

I think that's about right.

If you want to go for the "seat of the pants" style you got to the Mun with, you can set yourself up for intersecting orbits by burning prograde to get to the outer planets, or retrograde to get to the inner planets.

Prograde - center the map on Kerbin, zoom out a little, orient the map so that you know precisely which direction the Sun is. Assuming a prograde equatorial orbit, start a burn in the prograde direction (90) some time between late afternoon and midnight. Your "escape trajectory" from Kerbin should be prograde and outward. On the map, zoom way out until you can see the orbit of your target, and watch until the orbits intersect.

Retrograde - same procedure, but start the burn in the prograde-to-Kerbin direction (90) some time between pre-dawn and noon, so that your ejection is retrograde and inward. Similarly, zoom way out until you can see your orbits intersecting, then cut the burn.

Once you've got crossing orbits, you need a second burn at the ascending or descending node to match the orbital plane of your target.

Once you reach the orbital intersection, check out your position and orbital resonance with your target .. you can usually make a single burn that will set you up for a rendezvous "next lap", but sometimes patience and letting several laps pass will serve you better.

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For a middle ground, you can use Kerbal Engineer Redux, which will calculate the correct ejection angle for you -- rather than just burning "sometime between dusk and midnight", you'll get a "start your burn at 119.823487 degrees from prograde" .. and a marker telling you your current angle to prograde. Easy enough -- this should help with #3, as your orbital intercept distance will be fairly small. If your burn was perfect, you'll actually intercept, but generally, I find that I can make a slight adjustment at the ascending-node/descending-node burn to achieve an SOI intercept by either adjusting radial-in/radial-out or adjusting my prograde/retrograde node in addition to the normal-plus or normal-minus adjustment.

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Alternately, ORDA or MechJeb can just about handle it for you.

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If you'd rather get super into the planning and firing off the mission, then I suggest olex's website, http://ksp.olex.biz/, a.k.a. Interactive Illustrated Interplanetary Guide and Calculator for KSP. It'll give you the data you need to plot a minimum-delta-V transfer -- the Phase angle, the Ejection angle, and the delta-V you will need for your ejection burn -- but its up to you to apply that in-game.

You could calculate angles by eye on the Map view, or you might use Protractor, Kerbal Engineer Redux, MechJeb, or ORDA to assist you. You will need to timewarp forward to that correct Phase Angle (planetary alignment).

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Personally, I tend to have multiple flights going, so I use "Kerbal Alarm Clock" to let me know when they're getting to their destinations -- or when the next burn is needed.

[tomf]

I have a massively complicated spreadsheet where I calculate the delta-v for each phase of the mission, then plan the engines and fuel to give me that delta v. The main advantage is that I can use a spreadsheet while at work and then build when I get home.

[FlyMario]

Wow thanks a lot! Very helpful information! Last night I tried to go back to Duna. I placed myself in a orbit around the sun above Duna. Of course I could land on Duna... in maybe 100 or so years when duna comes up behind me. Bad planning LOL

[dragoncannon]

I pre-plan my missions so that I can run multiple at the same time. Before I start, I make sure I know when I will have a proper launch widow. I figure out when will I have a return flight window. And I input those into Kerbal Alarm Clock so I can keep track.

At this point I decide on mission architecture. Single launch... multi launch... Probe... Kerballed... and design the neccisary hardware to complete said mission.

[Blackbird]

So there is a lot of fun in planning your Missions and everything and since a lot of people have some problems or just don't know how to do it I'm going to show you how I do it...just for the lolz

I usually do a lot of planning, notes and test before even thinking about launching something into outer space. Let's go trough a mission and see how it goes!. I will try to keep it simple and focus on the main points. Feel free to make your own points and expand your plans.

(PS. I'm from Germany, so please spare me and my english ;D )

A TRIP TO DUNA (?)

At first, we start to set a clear objective about what we wanna achive and what the outcome should look like:

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MISSION: I want to set a little base up on duna with two Landers to hold 4 kerbals and a rover to explore the planet a bit.

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As easy as this step sounds, a lot of people don't get any further because they don't know how to move on. The next steps are the way I like it and it's up to you how you do them.

One thing I recomend though is that you use mods or webpages to get the information you want and need, since a lot of usefull information isn't implemented in the game at the moment.

I only use the Kerbal Alarm Clock and Mechjeb, because both of them have all the information and functions I need to get the most out of missions. Well, lets move on:

FIRST: PUT DOWN YOUR NOTEPAD!

We know our mission so now it's time to write a little "Script" on how to accomplish our mission:

LOG: 1. Launch a Carrier into Kerbin Orbit (110km) and park it.

2. launch the two Landers and dock with the Carrier.

3. launch the rover and dock with the Carrier

4. refill the Carrier

5. departure for Duna (deltaV?,when to burn?)

6. Intercept and Aerobrake on duna and establish an Orbit (around 100-200km)

7. Land both Landers at Duna and establish the base. (deltaV? how to land?)

8. send the rover down (deltaV?)

9. The Carrier stays in Orbit for future uses

This simple Log makes future planning a lot more easier, since we can now focus on every single point and work in detail trough everything. find out if your list is complete and has every keyepoint of your mission in it. This kind of "Metascript" will take us trough our planning. (I will call it like this from now on if you don't mind )

This is only the start of the script! as soon as something about the mission comes to your mind make a note about it. I will show you the finished script I had at the end of this mission:

LOG: 1. Launch a Carrier into Kerbin Orbit (110km) and park it. (~5000m/s dV. RCS and Lights needed to dock)

2. launch the two Landers and dock with the Carrier.

3. launch the rover and dock with the transporter

4. refill the Carrier (if dV<3000m/s)

5. departure for Duna (about 1100 dV, Alarm Set for Duna)

6. Intercept and Aerobrake on duna and establish an Orbit (around 100-200km, aerobrake at around 10km)

7. Land both Landers at Duna and establish the base. (both Landers are docked to each other to Land together. ~70dV required. touchdown without engines required. RCS needed. Lights for Landing needed)

8. send the rover down (Skycrane needed. ~70dV to deorbit. Landing close to Base, RCS optional)

9. The Carrier stays in Orbit for future uses

Reminder: - at least 4 Kerbals needed

HOW MUCH FUEL DO WE NEED ANYWAY?

The next thing is to find out how much fuel we even need to get to duna. I searched a bit around the forum and found a nice spreadsheet about the Delta-v required to get to other planets. You can see that it takes about 1100m/s to get to duna. I want to have at least 2000m/s so i don't need to worry if something goes wrong and i have to make major changes wich may require some Delta-v. Since duna has an atmosphere we can use parachutes to land our equipment at Duna, so we only need a little bit of fuel to slow us down the last few km's if we are to fast so we dont smash into the surface. There is no real number on how much Delta-V you will need to land since it is mostly based on your skill, so the best thing is to test it on kerbin or use Hyperedit to make some tests on Duna.

So, our fully equiped transporter needs at least 1100m/s to get to duna. Lets make a note in our Metascript and move onto the next step:

PHASE ANGLE

Since we want to get to another planet we need to know when to start our burn towards Duna. This is the point where you can save the most delta-v if you do everything the right way. There are different ways to approach this step, you can use spreadsheets and try to read the angle from the mapview or you use differnt mods to help you out. If you want to know more about phase-angles and how to visit other plantes you should check the forum or youtube, there are a lot of people out there who will teach you anything about KSP .

The one thing you should know is that going into a stable orbit around sun and after that waiting for a burn to intercept Duna is not an option because you will waste a lot of fuel this way. We will let Kerbin do the solar orbit for us und just do the intercepting burn when the "window" has opened. The easiest way to set this up is to use the Kerbal Alarm Clock and set the timer for it as shown in the picture below:

As you can see, I set up an Alarm to 10 minutes before the so called window arrives and we will start our burn towards duna. However, because we need to dock everything together and refuel it we need to stop a few days earlier so everything is ready to go when the time comes. At the moment, i have about 188 days left before the window arrives. Since I dont want my kerbals to stay that long in space we are going to warp to about 30 days before the window for now. this should give us enough time to do the rest of the work and give our kerbals some rest.

So we know the Delta V we need and we have our timers set up. Now we can start to build our ships fitted for the mission. But where to start? Let me show you:

FORGING OUR WEAPPONS

The best way is to start from "last to first", wich means that we will first design our lander and rover, and after that the carrier to carry them.The reason behind this is that these Landers are the "first Stage" and we don't need to design them based on another stage. (We cant start with the carrier because we first need to know how heavy our payload will be)

you can design whatever you want, but there are a few things we need to allways keep in mind when building ships:

1. make them as light as possible and design them for their purpose, nothing more, nothing less.

2. allways keep your main goal in mind as well as your other designs to make them work perfectly together

3. check twice if you didn't miss anything. (jeb doesn't like it when he can't climb out of the craft because u messed up and forgott to put a ladder on it)

4. ALLWAYS check your Script for the things your ship has to do and check if it is able to fullfill it's tasks

With that in mind, let me show you what i came up with for this mission:

1. THE LANDERS

I want to land both of them at the same time so I don't have to land one first and after that try to land the other one next to it. This needs extra fuel and a lot of trial and error because they don't have wheels and I think it is possible to land both at the same time since I designed them so that they don't need an engine to land. The plan is to dock them both together after they undocked with the Carrier and deorbit them together. At an altitude of about 11km i will decouple them and while mechjeb/ASAS will hold one of them steady I will use RCS the keep the other one close while they both decent next to eachother.

I RECOMMENT that you use Hyperedit to test your lander and see if it works the way you want. I don't like cheating, but there is no other way at the moment and there is nothing more frustrating to find out that your craft is useless after you managed to get to another planet.

Docked together, they got about 79m/s Delta-v and a lot of RCS wich is enough to get the orbit down into the atmosphere and land them. I tested them before and practiced to Land 2 crafts simultaniously and it worked, so they are ready for the mission

Next thing is the Rover:

2. THE ROVER

Not much to say here, i build a rover and attached a skycrane so it can land without problems. As you can see it has enough Delta V and a high enough TWR to land at Duna.

After we build our final stages we have to design the carrier:

3. THE CARRIER

As you may or may not notice, i put a lot of those crewcabs on top of my craft. Why you ask? well because they simulate the mass of the Rover and the two Landers. Of course we dont leave them on there we just need to simulate the mass in orbit so we know the Delta-V we've got with full payload. As you can see we got about 5000m/s of Delta-V wich is pretty much overkill for this mission, but since i like the simple design and i want to use this craft for further missions we will stick with it. If you wanted to return the carrier to Kerbin you would have enough fuel left to do so.

Our preperation is pretty much done to this point. The only thing we can do now is to look at our Script and Crafts again and search for mistakes we might have done or improve and expand the mission.

The rest from here on is to launch and fly your crafts and finish the mission you set yourself. Nothing to talk about anymore.

Here are some shots I did for this mission:

http://imgur.com/a/Bt1jz

Have a safe flight and thanks for listening to my stuff bye bye,

Blackbird

Edited April 26, 2013 by Blackbird
dat grammar

[PrathamK]

I take a paper instead, decide the mission, and write down the whole mission, step by step. Build the Spacecraft (Crewed vessels are defined), Now select my Launcher till 2 light, 4 medium, 3 Heavy, 1 Super-Heavy not tested (Crewed Vessels and Launchers are fixed).

Launch and use Mechjeb, all the mission.

In Interplanetary Missions, I send atleast 2 vessels at a time, who waits for anotherwindow and if one fails. If Flyby or Impactor no need of extras.

I need a mod for Pre-Launch sequences and Mission Planner.

[Spricigo]

2 hours ago, PrathamK said:

I need a mod for Pre-Launch sequences and Mission Planner.

Usually necroing 4yo threads are not useful,  but maybe this mod will be 

 

Edited May 7, 2017 by Spricigo

[PrathamK]

1 hour ago, Spricigo said:

Usually necroing 4yo threads are not useful,  but maybe this mod will be 

 

I got this, its the plan, I and others may need something that plans before launch. Well, useful to change the focus immediately, instead of searching the vehicles and clicking the right one or getting focus after clicking on planet.