1. The problem statement, all variables and given/known data I was wondering if you'd be able to help me with this problem: Given a two-stage launch vehicle with an engine that produces an Isp =400 sec, a payload mass of 10.000 kg, stage 1 structure mass of 10.000 kg, stage 2 structure mass of 10.000 kg, determine the mass ratio and the total mass of propellant required to reach LEO. Asume the total delta-v required is 7.700 m/sec. Determine the detal-v after each stage and the propellant mass for each stage. 2. Relevant equations Isp=(i/deltampropellant*g)=C/g Delta-v=Cln(M0/Mf) Delta-v=Cln(MR); MR=Mass Ratio M0=Mf*e(delta-v/C) Mtotal=Mstructure+Mpropellant+Mpayloand For a two-staged rocket: Mtotal=Mstage1structure+Mstage1propellant+Mstage2structure+Mstage2propellant+Mpayloand Delta-vtotal=g*Isp*ln(M0/Mf) The mass ratio for stage 1 is: MR1=Mtotal/(Mtotal-Mpropellant1) 3. The attempt at a solution I was trying to solve this problem with a Mf=10.000 kg +10.000 kg=20.000 kg, C=9.8m/s2 and a delta-v=7.700m/seg, then a find M0 replacing the equation, but I realized that this M0 is probablye the Mf of the stage 1...That two-stage rocket confuses me. As you can see I'm lost. I don't need you to solve the problem for me, just give me guidelines to resolve and so I can leave my confusion. I thank you for your attention and time spent.