Rocket Science Questions

Rocket science has uncountable applications, from launching satellites to testing ballistic missiles. The propulsion of rockets is based on a fundamental kind of motion, and one needs to be familiar with Newton’s Laws of Motion to understand it.

Important Questions on Rocket Science

1) In a gravity-free, drag-free environment, what is the nature of the trajectory of rockets?

a) Straight-line path, one-dimensional

b) Curved path, three-dimensional

c) Straight-line path, three-dimensional

d) Curved path, two-dimensional

Correct Option: (a)

Explanation: Since the only force acting on the rocket is its thrust, and it acts in the flight direction, a straight-line, one-dimensional acceleration path is followed in such conditions. The flight path will become curved under the influence of gravity.

2) In an ideal chemical rocket engine, which among the following is not a feature of the combustion chamber?

a) Higher transient time

b) Higher temperature

c) Higher velocity of flow

d) Low pressure

Correct Option: (a)

Explanation: In an ideal chemical rocket engine, the transient time is very low to confirm that the flow and related procedures are stable and remain constant at all times. Also, an ideal chemical rocket engine has a high temperature, high pressure, and low flow velocity.

3) What will be the estimated amount of energy loss due to the transfer of heat to the walls of the rocket for a typical real rocket engine?

a) 60%

b) 50%

c) 5%

d) 1%

Correct Option: (d)

Explanation: Due to the transfer of heat to the walls, the energy loss is generally less than 1% and rarely may go up to 2% of the total energy. Due to this reason, the effects of heat transfer can be ignored in real rockets.

4) The effective propellant fraction can be reduced by which of the following factors?

a) Increase in temperature at the inlet of the nozzle

b) Favourable nozzle area ratio

c) Lower chamber pressure

d) Higher system inert mass

Correct Option: (d)

Explanation: The ratio of the mass of propellants to the initial mass of the system is known as the effective propellant fraction. Therefore, the total initial mass(m_o) will increase if inert mass(m_f) increases.

5) For single-stage vehicles, gravitation free and drag-free space flight, what should be the practical value of the mass ratio that is (Initial mass/inert mass)?

a) 3000

b) 4000

c) 400

d) 20

Correct Option: (d)

Explanation: Spherical shape of the rocket is desirable in a single-stage rocket vehicles system. Even though it may not be the easiest to manufacture, it can help to minimise weights and lateral loads. Therefore, single-stage rocket vehicles can have a mass ratio up to about 20.

6) For multistage vehicles, gravitation free and drag-free space flight, what should be the practical value of the mass ratio that is (Initial mass/inert mass)?

a) 3000

b) 300

c) 30

d) 200

Correct Option: (d)

Explanation: In multistage vehicles, the rocket is split into many segments in which each of the sections is a separate propulsive system, and in this case, it can have mass ratios that exceed 200.

7) For orbital adjustments, the rocket engines used are also named as _____.

a) Propulsion boost system

b) Secondary propulsion system

c) Strap-on motors

d) Auxiliary rockets

Correct Option: (d)

Explanation: Auxiliary rockets also help in the purpose of attitude control manoeuvring apart from orbital adjustments. Auxiliary rockets are also named as reaction control systems.

8) How many thrusters are required for the application of clean torques in three directions?

a) 16

b) 10

c) 12

d) 6

Correct Option: (c)

Explanation: To generate clean torques in the three orthogonal directions, 12 thrusters are required. Roll, pitch and yaw thrusters are also included with control valves.

9) What should be the nature of the working substance for an ideal rocket?

a) Anisotropic

b) Amphoteric

c) Homogeneous

d) Heterogenous

Correct Option: (c)

Explanation: Homogeneous means that the configuration and character of the substance are uniform throughout. Hence, the working substance and chemical products should be homogeneous.

10) Which is the correct statement for an ideal rocket among the following?

a) The boundary layer cannot be neglected, and all frictional effects are not present.

b) Shock waves are allowable

c) Propellant flow is constant and steady

d) The extension of the working fluid is stable, but the flow is not necessarily uniform

Correct Option: (c)

Explanation: Propellant flow is considered to be constant and steady in an ideal rocket. Along with the possible cut-offs in flow, such as shock waves, all types of boundary layers and frictional effects are neglected in such vehicles. The expansion of the working fluid is uniform as well as steady.

Practice Questions

1) How does rocket fuel burn in space without oxygen?

2) What is rocket propulsion?

3) What are the fuels used in rockets?

4) What is rocket science?

5) What is thrust?

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