Ask Question
29 July, 02:06

A total 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?

+3
Answers (1)
  1. 29 July, 03:53
    0
    102000 kg

    Explanation:

    Given:

    A total Δν = 15 km/s

    first stage mass = 1000 tonnes

    specific impulse of liquid rocket = 300 s

    Mass flow rate of liquid fuel = 1500 kg/s

    specific impulse of solid fuel = 250 s

    Mass flow of solid fuel = 200 kg/s

    First stage burn time = 1 minute = 1 * 60 seconds = 60 seconds

    Now,

    Mass flow of liquid fuel in 1 minute = Mass flow rate * Burn time

    or

    Mass flow of liquid fuel in 1 minute = 1500 * 60 = 90000 kg

    Also,

    Mass flow of solid fuel in 1 minute = Mass flow rate * Burn time

    or

    Mass flow of solid fuel in 1 minute = 200 * 60 = 12000 kg

    Therefore,

    The total jettisoned mass flow of the fuel in first stage

    = 90000 kg + 12000 kg

    = 102000 kg
Know the Answer?
Not Sure About the Answer?
Find an answer to your question ✅ “A total Δν of 15 km/s is required to achieve an interplanetary mission. The proposed rocket has two stages. The first stage alone has a ...” in 📘 Physics if you're in doubt about the correctness of the answers or there's no answer, then try to use the smart search and find answers to the similar questions.
Search for Other Answers