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Dianainthesky
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Homework Statement
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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.
Homework 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)
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.
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