Orbital mechanics (Kepler’s laws, Hohmann transfer) MCQs – Aerospace

1. The first of Kepler’s laws states that:
(A) Planets move in elliptical orbits with the Sun at one focus
(B) Planets move in circular orbits around the Sun
(C) The speed of a planet is constant in its orbit
(D) The area swept by a planet in its orbit is constant

2. Kepler’s second law indicates that:
(A) A line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time
(B) The orbital period of a planet is proportional to its distance from the Sun
(C) Planets move faster when closer to the Sun
(D) Planets move slower when further from the Sun

3. Kepler’s third law states that:
(A) The square of the orbital period of a planet is proportional to the cube of its average distance from the Sun
(B) The speed of a planet is constant in its orbit
(C) The shape of the orbit is a perfect circle
(D) The time taken for a planet to complete one orbit is constant

4. In a Hohmann transfer orbit, the spacecraft:
(A) Moves from a lower circular orbit to a higher circular orbit
(B) Moves from a higher circular orbit to a lower circular orbit
(C) Moves along an elliptical path between two circular orbits
(D) Moves in a circular path around the Earth

5. The primary advantage of a Hohmann transfer orbit is:
(A) It is the most fuel-efficient method for changing orbits
(B) It provides the fastest transfer between orbits
(C) It minimizes the time spent in space
(D) It ensures the spacecraft remains in a circular orbit

6. The velocity required for a spacecraft to enter a circular orbit from a Hohmann transfer is:
(A) Greater than the velocity at the periapsis of the transfer orbit
(B) Equal to the velocity at the periapsis of the transfer orbit
(C) Less than the velocity at the periapsis of the transfer orbit
(D) The same as the velocity at the apoapsis of the transfer orbit

7. The Hohmann transfer orbit is used to:
(A) Change the semi-major axis of an orbit with minimal energy expenditure
(B) Achieve a higher speed in the same orbit
(C) Increase the altitude of the orbit quickly
(D) Decrease the speed of a spacecraft in the same orbit

8. The semi-major axis of an elliptical orbit can be determined from:
(A) The sum of the periapsis and apoapsis distances divided by two
(B) The difference between the periapsis and apoapsis distances
(C) The average of the periapsis and apoapsis velocities
(D) The product of the periapsis and apoapsis distances

9. The eccentricity of an orbit describes:
(A) The deviation of the orbit from a perfect circle
(B) The distance of the orbit from the central body
(C) The speed of the orbiting body
(D) The time period of the orbit

10. For a circular orbit, the eccentricity is:
(A) Zero
(B) One
(C) Less than one
(D) Greater than one