http://apcnasa3ozl2j74htizuzba5b6nhugbg2qze2nrz43siunkct555fpid.onion
Since propellant is used continuously during the burn, and thus the mass of the rocket decreases accordingly, it is necessary to use calculus to derive the desired relationship between D V, I sp , the total mass of the rocket before the burn, M 0 , and the mass of the rocket after the burn, M b . Note that the initial rocket mass, M 0 , is the sum of the propellant mass expelled during the burn, M p , and the final mass of the rocket after the burn, M b .