Is there any way to know how many tons can my rocket lift into LKO?

[mySynka]

I found a post that asked the same question. A user by the name of GoSlash27 responded to it with an equation, but I'm not sure what he means with some of the names and ways he names the unknown values (link). I would've loved to ask them what they meant with some of these definitions, but unfortunately the comment and the post are almost a decade old at this point. And, between 9 years ago and today, we've had a lot of changes, so maybe the equation is no longer correct.

That's why I'm asking any of you that knows, how can I know the maximum tons to LKO that my rocket can carry? Maybe there's a website, or perhaps an equation, but I really don't know. I'll be happy with any of your answers!

 

[Dman979]

Hey @mySynka, welcome aboard! Good news- that equation is still correct. It's one of the basic equations in spaceflight, and should be correct for as long as we understand physics.

The aerodynamic model has changed since 2014. You'll need around 3,500 to 3,800m/s of delta-V to get to LKO, but everything else @GoSlash27 posted seems accurate.

[Fraktal]

If you're using KER, it's roughly the mass with which you'll get 3400 m/s of dV if your sea-level launch TWR is at least 1.4.

• Any lower dV and you won't reach orbit.
• Any lower TWR and you'll lose too much dV to pushing against gravity. For an upper stage, you can get away with less TWR but too low and you won't be able to circularize in time.

That's really the best I can say.

Edited February 23, 2023 by Fraktal

[mySynka]

2 minutes ago, Fraktal said:

If you're using KER, it's roughly the mass with which you'll get 3400 m/s of dV if your sea-level launch TWR is at least 1.4.

• Any lower dV and you won't reach orbit.
• Any lower TWR and you'll lose too much dV to pushing against gravity.

That's really the best I can say.

Thanks for this answer! This method is easy and has given fairly realistic results. Turns out my rocket can lift roughly 2.3 tons to LKO while only costing 6k funds. Beat that, Rocket Lab!