JNTU
JNTU B.Tech II INTRODUCTION TO SPACE TECHNOLOGY Previous Question Paper (September/October - 2023 - R13)
Note: i) Question paper consists of Part A, Part B. ii) Part A is compulsory, which carries 25 marks. In Part A, Answer all questions. iii) In Part B, Answer any one question from each unit. Each question carries 10 marks and may have a, b as sub questions.
PART-A
Define the terms ‘specific Impulse and propellant ratio’.
Answer
Specific Impulse (Isp) is a measure of the efficiency of a rocket engine, defined as the total impulse delivered per unit weight of propellant consumed. It is expressed in seconds and represents the duration for which one unit weight of propellant can provide one unit of thrust.
Propellant Ratio, often referred to as the mixture ratio, is the ratio of the mass flow rate of the oxidizer to the mass flow rate of the fuel in a liquid-propellant rocket engine. It is a critical parameter for determining the combustion efficiency and the chemical energy release of the propellant combination.
Explain the working principle of liquid propellant rocket.
Answer
A liquid propellant rocket operates on the principle of Newton's Third Law of Motion, where high-pressure combustion gases are expelled through a nozzle to generate thrust. The system consists of separate tanks for a liquid fuel (e.g., kerosene or liquid hydrogen) and a liquid oxidizer (e.g., liquid oxygen), which are fed into a combustion chamber by turbopumps or pressurized gas systems.
Inside the combustion chamber, the fuel and oxidizer mix and ignite, producing high-temperature, high-pressure gases. These gases are accelerated to supersonic speeds through a de Laval nozzle, converting thermal energy into kinetic energy. The resulting high-velocity exhaust stream creates an equal and opposite reaction force, providing the forward thrust necessary for propulsion.
What do you mean by Aerobraking?
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Explain in brief about the concept of double-dip.
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State Kepler’s Third law and state the assumptions.
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Explain the concept of Auroral activity with neat sketch.
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What do you mean by Magnetopause and Magneto-tail?
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How many sets of initial conditions can we make use of for solving the two-body equation of motion? Give an example of one set of these.
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Explain the importance of Altitude loss due to gravity.
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Explain how the weather conditions are going to affect the launching of a space vehicle.
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PART-B
Obtain an expression for the ideal velocity of a multi-stage rocket of N stages traveling in a free space.
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Explain the reasons for a rocket designer to choose the multi-staging concept rather than a single-stage design.
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A rocket has the following data: Propellant flow rate = 5 kg/s, Nozzle exit diameter = 11 cm, Nozzle exit pressure = 1.02 bar, Ambient pressure = 1.013 bar, Thrust = 7 kN. Determine the effective exhaust jet velocity, actual exhaust jet velocity and specific impulse.
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If the re-entry velocity of a spacecraft is 7.4 km/s and the re-entry flight path angle is 10 degrees, find out the maximum deceleration experienced by the vehicle and the altitude at which it occurs. The Ballistic Coefficient of the vehicle is 1,000 kg/m2.
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Describe the two methods to determine the hypersonic drag coefficient for a re-entry space vehicle.
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Write a short note on ‘the three competing re-entry requirements’.
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A tracking station reports that an approaching object has a velocity of 10,000 m/s at an altitude of 98,000 km and that the velocity vector makes an angle of 20 degrees with r (the position vector). Will the object hit the Earth? If not, what is the altitude and velocity at the closest passage?
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Write a brief note on plane changes of an orbit.
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A communication satellite is in a 322 km circular parking orbit but not in a desired plane. Find the Delta V required to shift the plane by 10 degrees, without changing the radius.
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Explain the effect of static charge accumulation on the performance of electronic components of a space vehicle.
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Explain how magnetic desaturation is useful in controlling attitude of a spacecraft.
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Discuss the concept of Shielding to the space vehicle against charged particle radiation.
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Justify the statement that “mission operations often form the background for a space mission”.
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Why do signal losses occur in the earth’s atmosphere for satellite communication? Write a note on ionospheric effects.
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Distinguish between down link and forward link, related to communication of information transfer between ground control station and a spacecraft.
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Explain in brief about the importance of team responsibility and mission diversity in space missions operation.
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