Finding max. payload mass: Tool

[Starseeker]

If you've ever wanted to know how much mass your rocket can lift, then this tool I've made can help you out:

https://docs.google.com/spreadsheets/d/1-NVhhObOQflRRpe6Az-spMVG_vFvmjsSk4uOiUAi2nI/edit?usp=sharing

Simply enter the vales requested in the green input fields, and take a look at the blue output fields. Play around with the Payload Mass value until you find the number at which the bottom-most output field changes. That value is the maximum mass your rocket can lift into LKO, assuming a ÃŽâ€v requirement of 3400 m/s. You can also enter a custom ÃŽâ€v goal below the payload mass, and see if that mass has that ÃŽâ€v.

The multiple "stage" columns are for engine stages only. You don't have to fill all of them. I recommend a mod like MechJeb or Kerbal Engineer to help you figure out the exact mass (down to 0.001 metric tons).

Thanks to Scott Manley for putting out

that inspired me to do this, and showed me how to calculate the values.

If you have a question or feedback, please post it below! I would love to improve this tool.

Edited September 19, 2015 by Alex33212
Correcting dV value; adding notes on new features

[Superfluous J]

Two suggestions:

Make the link a bit easier to find. I read through the post twice before I saw it

Make dV a variable the user can put in. I can land on Minmus with 4700dV and some luck.

[Starseeker]

Thanks for the feedback! I've put the link in a far more visible position.

As for the second suggestion, do you mean the ÃŽâ€v goal? I could do that real quick. If you mean something else, could you clarify? I would love to hear what I should add to make it better.

Also, the reason I use 4700 as the ÃŽâ€v goal is because it's at the high end of the ÃŽâ€v requirement range for LKO listed by the KSP wiki, and it's better to bring extra ÃŽâ€v and not need it than to not bring it and need it.

Edited September 6, 2015 by Alex33212

[Violent Jeb]

Also, the reason I use 4700 as the ÃŽâ€v goal is because it's at the high end of the ÃŽâ€v requirement range for LKO listed by the KSP wiki, and it's better to bring extra ÃŽâ€v and not need it than to not bring it and need it.

The LKO requirement listed by the KSP wiki is using this as reference, which is pre 1.0.x

http://i.imgur.com/CEZS1.png

The current delta V map is here [1.0.4 on image]

http://i.imgur.com/q0gC9H7.png

and 3400 m/s is the regarded figure. 4 km/s is more than enough even with a margin. 4700 dv is simply creating a massive launcher stage. You may want a massive launcher stage, but i am 100% certain you can escape kerbin SOI with that much potential.

use mechjeb and your calculator to confirm these values if you'd like, but thank you for the doc regardless

edit; if you're new around here, sometimes the wiki gets a little outdated just fyi

Edited September 7, 2015 by Violent Jeb

[Superfluous J]

Sorry yeah I meant "dV to LKO."

[Starseeker]

The LKO requirement listed by the KSP wiki is using this as reference, which is pre 1.0.x

http://i.imgur.com/CEZS1.png

The current delta V map is here [1.0.4 on image]

http://i.imgur.com/q0gC9H7.png

and 3400 m/s is the regarded figure. 4 km/s is more than enough even with a margin. 4700 dv is simply creating a massive launcher stage. You may want a massive launcher stage, but i am 100% certain you can escape kerbin SOI with that much potential.

use mechjeb and your calculator to confirm these values if you'd like, but thank you for the doc regardless

edit; if you're new around here, sometimes the wiki gets a little outdated just fyi

Thanks for the info! I'll update the default dV requirements. Unfortunately, I'll have to respec my lifters...

- - - Updated - - -

Sorry yeah I meant "dV to LKO."

Ok, will add. Thanks again for the feedback!

- - - Updated - - -

Violent Jeb and 5thHorseman, I've made the changes you've suggested. Thanks for the feedback, it made this tool better than before!

[Starseeker]

Quick note: after the dV req. update, I've found that one of my lifters (so far the only one I've re-specced) has nearly doubled in payload capacity!

[Starseeker]

Update: switched the multiple-engines guide link to one easier to use (even I didn't know how to use what I had linked before).

[xebx]

This site has very good multiple engines analysis : http://meithan.x10.mx/KSP/engines/, a very good way to see what are the possibilities for a given payload and deltaV.

3400 m/s deltaV is a safe value to LKO, a good launcher and MJ with the good values and it's ok.

I did 3350 m/s deltaV (vac) to LKO recently and payload fraction was 26% (see here and here)

Edited September 19, 2015 by xebx

[NathanKell]

Delta V required to reach orbit is heavily influenced by TWR; a fixed value of 3400 can be too much or too little.

(for the Earth case, see http://www.silverbirdastronautics.com/LVperform.html for a simple but solid model.)