JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech II INTRODUCTION TO SPACE TECHNOLOGY Previous Question Paper (March - 2022 - R13)
Answer any five questions. All questions carry equal marks.
Main
A rocket of total mass 100 tonnes carrying a spacecraft of 5 tonne and engine develop a constant exhaust velocity of 3500 m/s. The structural mass is assumed to be 15% of the total mass. Calculate final velocity of rocket.
Answer
To calculate the final velocity of the rocket, we use the Tsiolkovsky rocket equation: Δv = v_e * ln(m_0 / m_f). Given the total initial mass m_0 = 100,000 kg, the structural mass is 15% of the total mass (15,000 kg), and the spacecraft mass is 5,000 kg. The propellant mass is the remaining mass of the rocket system. Assuming the structural mass and spacecraft mass constitute the final dry mass m_f, we have m_f = 15,000 kg + 5,000 kg = 20,000 kg. The propellant mass is 100,000 kg - 20,000 kg = 80,000 kg.
The final velocity of the rocket is approximately 5632.9 m/s.
Write about necessity of Cooling in liquid –fuelled Rocket engines.
Answer
In liquid-fuelled rocket engines, combustion temperatures often exceed 3000 K, which is significantly higher than the melting point of the materials used to construct the combustion chamber and nozzle. Cooling is essential to prevent structural failure, melting, or thermal degradation of these components.
The primary methods of cooling include:
- Regenerative Cooling: The cryogenic fuel or oxidizer is circulated through cooling jackets surrounding the combustion chamber walls before being injected into the combustion zone. This preheats the propellant and cools the chamber walls.
- Ablative Cooling: The inner wall is lined with a material that absorbs heat through chemical decomposition and erosion, carrying heat away as the material vaporizes.
- Film Cooling: A thin layer of fuel or a coolant is injected along the inner walls of the chamber to create a protective thermal barrier between the hot combustion gases and the metal surface.
- Radiation Cooling: The engine components are designed to radiate heat away into the surrounding environment, typically used for nozzles operating in vacuum conditions.
Write short notes on the following:
i) Effects of charged particles on the satellite
ii) Shielding to the space vehicle against charged particle radiation
Answer
Sign in to view the complete answer paper.
Explain Injection process and types of injectors used in Liquid propellant rocket system.
Answer
Sign in to view the complete answer paper.
Deduce an equation for Velocity burnout in Lifting body Re-entry. Explain all the terms in equation.
Answer
Sign in to view the complete answer paper.
Sketch and explain various types of Atmosphere Re-entry vehicles with suitable examples.
Answer
Sign in to view the complete answer paper.
Illustrate the process during flight in to orbit vehicle must be rotated and lift acted down position.
Answer
Sign in to view the complete answer paper.
If the re-entry velocity of a space vehicle is 10 km s-1 and the re-entry flight path angle is 15°. Find out the maximum deceleration experienced by the vehicle and the altitude at which it occurs. The Ballistic Coefficient of the vehicle is 1,180 kg m-2.
Answer
Sign in to view the complete answer paper.
Define Circular orbit and derive an equation in terms of velocity at any point on a Circular orbit under two body motions?
Answer
Sign in to view the complete answer paper.
In general co planner maneuver, consider an initial direct, circular earth orbit of radius 8100 km and a final direct, co-planner, elliptical orbit with e=0.1 and rp= 7500 km. What velocity change is require to make the transfer?
Answer
Sign in to view the complete answer paper.
With the help of neat sketches explain how to use a plane change combined maneuver, with an example.
Answer
Sign in to view the complete answer paper.
A Space vehicle is in an orbit with a semi-major axis of 3,500 km and an eccentricity of 0.1. Calculate the time it takes to move from a position 32 degrees past perigee to 64 degrees past perigee.
Answer
Sign in to view the complete answer paper.
Describe in detail about attitude control for spin stabilization of a spacecraft.
Answer
Sign in to view the complete answer paper.
Illustrate the phenomena of Torque free axis symmetric rigid Body with suitable sketches.
Answer
Sign in to view the complete answer paper.
Define Space mission. Bring out the mission phases and core operations for team responsibilities.
Answer
Sign in to view the complete answer paper.
Discuss about various communications satellite systems which are presently operational in space with suitable examples.
Answer
Sign in to view the complete answer paper.