Atotal δν of 15 km/s is required to achieve an interplanetary mission. the proposed rocket has two stages. the first stage alone has a mass of 1000 tonnes and consists of 10 solid rocket boosters and a liquid rocket motor. the liquid rocket has a specific impulse of 300 s and a fuel mass flow rate of 1500 kg/s. the solid rocket boosters have a specific impulse of 250 s and a fuel mass flow rate of 200 kg/s. the first stage burn time is 1 minute. the first stage is jettisoned immediately after burn-out. the second stage has an initial mass of 150 tonnes. the second stage motor provides an effective exhaust velocity of 4 km/s and has a structural coefficient of 0.05. the rocket carries a 2 tonne payload. a. what is the jettisoned mass of the first stage?