I Created a Cheat Sheet! Yeah!

[inigma]

'Bout time all this info got in one place on the wiki.

Kerbal Space Program's Rocket Scientist Cheat Sheet Delta V Maps and Equations for Your Reference So You Can Get From Here to There and Back Again.

http://wiki.kerbalspaceprogram.com/wiki/Cheat_Sheet

I think many of you might find it useful. Feel free to modify.

[1096bimu]

errr why can't I just use Mechjeb?

[inigma]

the cheat sheet is for those who want to master the basic math before relying on mechjeb and for those who don't want to over-engineer their builds. Currently mechjeb and engineer redux don't calculate true dV taking into account atmospheric transitions, so those mods give you info which basically way overshoot your dV target in the design stage.

[1096bimu]

the cheat sheet is for those who want to master the basic math before relying on mechjeb and for those who don't want to over-engineer their builds. Currently mechjeb and engineer redux don't calculate true dV taking into account atmospheric transitions, so those mods give you info which basically way overshoot your dV target in the design stage.

and knowing that, you can take it into account and just design with less DV? It's not like you told us how to calculate atmospheric transitions, you just gave us a number and said, there, you'll use 1000 in the atmosphere.

Besides, I don't see anything that needs mastering, it's just plug into the equation and punch the calculator.

Edited June 25, 2013 by 1096bimu

[inigma]

ok, so the cheat sheet puts all of this in one place. why do I get the feeling by you that it's not a needed page then?

[Vanamonde]

errr why can't I just use Mechjeb?

For those who want to play the game instead of watch Mechjeb play it, inigma was kind enough to collect some useful information. If you don't appreciate or need his efforts, then there's still no need to denigrate them.

[1096bimu]

For those who want to play the game instead of watch Mechjeb play it, inigma was kind enough to collect some useful information. If you don't appreciate or need his efforts, then there's still no need to denigrate them.

well, use flight engineer, or just use MechJeb for information. I don't suppose that you'll be unable to prevent yourself from using the autopilot options?

For those of us, who aren't interested in practicing a skill easily done by a few lines of code, even we can choose to not use autopilot.

[hoojiwana]

That's a great combined resource for people to use inigma. Perhaps a small, simple applet or something that people could quickly tap in their own numbers might be helpful, since I'm sure there are those amongst the KSP playerbase who might not correctly be able to follow the equations.

Of course there are other options such as using Kerbal Engineer ingame, but there are plenty of people who wish to play the game without the use of mods, and the ability to see just how things are worked out in KSP might be of benefit to some. KSP is after all often used as an educational aid, and being able to combine the "practical" side of mathematics with the equations side can only be a good thing.

[kahlzun]

Good idea! Newbs especially would benefit from a central repository, however...

200 Newton rocket engine on a 15 ton rocket launching from Kerbin Space Center.

TWR = 200 Newtons / ( 15 Tons total Mass X 9.86 m/s2 ) = 1.36 which is > 1 which means liftoff! .

Point 1: 200 Newtons is 0.2 in that calculation, the engines are rated in 'kilonewtons'. The ion engine puts out 500 Newtons, and that can't even lift its own weight against Kerbin gravity.

Point 2: Gravity at KSC is 9.81 ms, not 9.86.

Delta V (dV)

Use this equation to figure out the dV per stage:

Equation:

dV = ln ( Starting Mass / Ending Mass ) X Isp X gravity of planet you're on

Local gravity does NOT affect deltaV: the conversion is ALWAYS 9.81 (Earth/Kerbin sea level gravity)

[Spaceisbeautifulul]

-snip-

Anyways, inigma, thank you, I really needed this, because I don't like to install mods for just one reason. So thank you.

Edit: Woah, ninja'd, I was replying to "Whatisthisidonteven".

Edited June 25, 2013 by KasperVld

[Brabbit1987]

My motto is, if there is an easier way, then do it. Why work hard when you can work smart?

That being said, I rather just use a mod to do the calculations for me. This doesn't mean I couldn't learn, it is more of the fact that it saves a lot of time.

I would do the same in real life. Instead of constantly doing the math over and over again, I would take the equation and use a computer to calculate it instead.

Course I am not telling anyone this information is pointless, for those who like to take the long route, by all means go ahead =^.^=. Oh, I should also mention, I like using computers because it cancels out human error, meaning you are also less likely to run into issues with calculations.

[hoojiwana]

Something else that could be added is nyrath's Kerbal Nomogram. Using that you can help find a rough guide on how much propellent you need to get to somewhere.

[ddavis425]

This cheat sheet has a lot of good resources available. Sadly, it only took one user to derail a thread that had potential.

[OdinYggd]

This cheat sheet has a lot of good resources available. Sadly, it only took one user to derail a thread that had potential.

Experts are on the job. Try to stay to the topic at hand, everything else is being delt with.

This cheat sheet really has a lot of potential who want to set up their own calculations spreadsheet.

In fact, using this knowledge I might try flying a mission without using mechjeb, since it'll be more fun for me to actually do the calculations on my own for a change. Half the fun of tinkering is solving for how it all works.

[Procyon]

If you want to use MECHJeb, by all means go ahead.

Some people just LIKE to do math.

Why do some people seem to dislike this? If they want to do the math, LET EM.

It in no way, shape, or form affects you, or your game. But for some reason this disturbs some, apparently, fairly deeply. Maybe because they are not so good at the math and have been taught to " let the calculator do it"?

and before I get flamed I use Eng Redux because im lousy at math, been out of practice for to many years

[stupid_chris]

Woah there Inigma, I see you pulled out my technique for calculating Atmospheric dV

Okay, I see some people have been questionning the "1000m/s in atmosphere". That actually comes from me, Inigma was wondering how to accurately find out how much the transition costs so I told him how I do. I think it's just relevant to say it's a grosso modo technique, it's more of an approximation I took on a guess and that turns out to actually work. I'll just repost my reply earlier to show you what I mean:

"Alright here it goes. Screenhot of my rocket on the launchpad:

So let's do the math. Here, stage 4, 3 and 2 are used to get in orbit. So let's start with stage 4, who has 1476 of delta V in atmosphere and 1724 in vacuum. Thus, it has this 1000m/s to himself. So, if we take away, 1000m/s from the fourth stage atmospheric delta V, theres 476m/s left. 476/1476=0.32, meaning that 32% of the fuel will be left in the stage when it passes the "atmospheric limit". So, there will be 32% left of the vacuum delta V, so 0.32*1742=562m/s. So, for our first stage, wel'll get 1000m/s atmospheric + 562 vacuum, meaning we get a total of 1562m/s from our first stage. Then the other stages are considered vacuum, so 1562+1863+1197 = 4595m/s of delta V in total for our launch stage. To prove this out, I launched it with MechJeb to an altitude of 80k to have the most precise results possible:

Here we can see that the total delta V expanded to get into orbit is 4530m/s and there's roughly 125m/s left in the launch stage, so the total delta V of the rocket was actually 4655m/s, which is only 60m/s from the predicted 4595m/s. So yeah that's how I calculate my stuff. If you have multiple stages to get the first 1000m/s, just calculate the first as atmospheric and you do the same math as I did above to approximate the delta V of the one who goes through the limit.

The results will vary a bit depending on your TWR and such but it should usually be pretty darn accurate."

So yeah, at least you guys know where this comes from. There's probably a more precise way to calculate it but I guess it would need integers and stuff, so I limited myself to that.

[EmissionGeneration]

-snip-

On the topic though, you ever thought about creating a Spreadsheet for people to use aswell? There are free Online ones out there like - http://doc.google.com -

Edited June 25, 2013 by KasperVld

[hoojiwana]

This cheat sheet really has a lot of potential who want to set up their own calculations spreadsheet.

In fact, using this knowledge I might try flying a mission without using mechjeb, since it'll be more fun for me to actually do the calculations on my own for a change. Half the fun of tinkering is solving for how it all works.

If you want to take it really far, figure out the flight plan and rocket design using pen and paper, and then fly the mission in EVA view. That should feel pretty authentic.

[Mr Shifty]

This has potential. Can I suggest:

- Add the Vis-Viva equation

- Use the MediaWiki TeX formatting for the equations (https://meta.wikimedia.org/wiki/Help:Displaying_a_formula)

[Pyotor Gagarin]

This info repository is a great idea inigma.

I've been keeping a folder of kerbal related info-graphics since I started browsing the forums. Maybe you can find something useful in there.

Also, consider cross-linking with the drawing board thread over in the tutorials subforum.

Thanks for the time and effort!

[inigma]

chris, i just now added credit where due. thanks good buddy.

everyone, feel free to update the cheat sheet with your own contributions/corrections. that's why i wikified the info so it can be corrected. i have no feelings over how much of the sheet gets edited, so edit away.