SpaceCars Posted September 23, 2014 Share Posted September 23, 2014 Hello! I'm a new KSP player. I've played the demo and then bought the game a few days ago. In career mode I did my first Mun landing (and return ), but I was frustrated by not having a record of my flights. That's why today I started a new career along with a website for my SpaceCars Aerospace Space Program. It is still a bit messy, but I hope it will give some of you a nice nostalgia for when you still was a clueless beginner.Now, onto my newbie question! I wanted to calculate the max payload to LKO (75km) for my newly designed lifter. How do I do this? I'm using the Kerbal engineer mod, so I know the Delta-V, TWR, I_sp, etc. I should be able to derive max payload from those right? Link to comment Share on other sites More sharing options...
NathanKell Posted September 23, 2014 Share Posted September 23, 2014 Welcome!Calculating payload is tricky; how much delta V is needed to reach orbit is a complex function of TWR and flight path, and how much delta V is available is a function not just of fuel carried but of how long you spend at what pressure in an atmosphere. As a general rule you should add payload until you have 4500m/s of *vacuum* delta V available; if you fly a decent ascent, that should be enough to get into orbit. Link to comment Share on other sites More sharing options...
SpaceCars Posted September 23, 2014 Author Share Posted September 23, 2014 Ah right, the ascent profile is also a factor. I looked into how to solve the Delta-V calculation in vacuum for mass, but with staging and having to calculate the remaining fuel after each stage it became a bit complicated. So I just added weight until I had 4500m/s remaining according to engineer. That was really helpful, thank you! Link to comment Share on other sites More sharing options...
Pecan Posted September 23, 2014 Share Posted September 23, 2014 The thread How do I calculate payload mass to orbit? is hidden in the tutorials section of the forum instead of gameplay questions.TL;DR -Launch capactity (tonnes) = ((Launch_Ratio * Mass_Dry) - Mass_Wet) / (1 - Launch_Ratio)Where :-Launch_Ratio = EXP(4,500 / (Isp * Gravity)) Link to comment Share on other sites More sharing options...
SpaceCars Posted September 23, 2014 Author Share Posted September 23, 2014 Ah thanks for the link! With multiple stages I still find using the KER and stacking weight easier than doing the calculation, but it is nice to know how to do it by hand.I should have guessed that I wasn't the only one with that question and should have done a diligent search first, whoops! Link to comment Share on other sites More sharing options...
SpaceCars Posted September 23, 2014 Author Share Posted September 23, 2014 SpaceCars Aerospace just completed its first orbital spaceflight above Kerbin! You can read the mission report here.Now that I'm keeping mission logs and doing mission planning I'm having so much more fun than in my other, more loosey-goosey, campaign! E.g. I knew that this orbiter would have to do its own circularizing burn, so it felt really great when that prediction came true. Link to comment Share on other sites More sharing options...
Pecan Posted September 23, 2014 Share Posted September 23, 2014 Nice work :-)Planning and designing are features I enjoy too, rather than just winging it. In case you didn't know you can post your mission reports on the forum in the section called, er, Mission Reports Link to comment Share on other sites More sharing options...
SpaceCars Posted September 23, 2014 Author Share Posted September 23, 2014 Thanks! I saw that but didn't think just posting a link would be much appreciated. So when I do a mission that's actually interesting, I'll reformat it and post it to that forum. I'm now putting my first probe, Robbie Mk1, into an orbit around the Mun. Link to comment Share on other sites More sharing options...
z26 Posted September 24, 2014 Share Posted September 24, 2014 decent ascentWas that an intended pun? Link to comment Share on other sites More sharing options...
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