Rocket mass ratio
= Rocket mass ratio
{title2=$R=M_{\mathrm{initial}}/M_{\mathrm{final}}$}
The <rocket mass ratio> compares the initial and final total rocket <masses> for a burn. It is <dimensionless>, and the ideal <rocket equation> becomes $\Delta v=u\ln R$. For the same fixed <rocket exhaust speed>, two successive burns with <rocket mass ratios> $R_1$ and $R_2$ have combined <rocket mass ratio> $R_1R_2$ and total <velocity> gain $u\ln R_1+u\ln R_2$.