Stage #:1
Please input the craft's stage name: Bogus Craft I
      Please enter the engine's ISP: Error--      Please enter the engine's ISP: 300
Please enter the craft's total mass: 1000
       Please enter the fuel's mass: 900
dV of this stage is 6774.19
Stage #:2
Please input the craft's stage name: BogusII
      Please enter the engine's ISP: 400
Please enter the craft's total mass: 800
       Please enter the fuel's mass: 700
dV of this stage is 8156.94
Stage #:3
Please input the craft's stage name: BogusIII
      Please enter the engine's ISP: 500
Please enter the craft's total mass: 300
       Please enter the fuel's mass: 200
dV of this stage is 5386.85
   Please enter your target dV: 5000
Please enter your engine's ISP: 300
   Please enter payload weight: 20
Efficient calculation of fuel mass gives fuel mass= 89.4272
fuelMass of 89.4272 achieved dV of 5000
Would you like to do this all again?! (y/n): n