# Talk:Tutorial:Advanced Rocket Design

From Kerbal Space Program Wiki

### Question: 9.81 m/s^2 in delta V calculations?

Isn't that figure the acceleration due to gravity on Earth at sea level?

I'm assuming that the devs used an earth-like parameter for Kerbin, and obviously this math is working for you; but do you use a different acceleration parameter when calculating the delta-V of your Munar return stage? --Hovissimo (talk) 19:45, 25 December 2012 (UTC)<P> No, the 'g' is a standard unit of measurement. Changing it would be like changing the length of a metre because the Mun "has less of them". Kahlzun (talk) 07:37, 2 January 2013 (UTC)

- Isn't that kind of arbitrary, though? Wouldn't Δv = Isp · ln(m
_{0}/m_{1}) make more sense? Ninenineninefour (talk) 14:48, 23 March 2013 (CDT)

- Isn't that kind of arbitrary, though? Wouldn't Δv = Isp · ln(m