Which of these orbital elements determines the size of the lunar orbit?

Eccentricity

Semi-major axis

Inclination

Argument of periapsis

Correct Answer : Semi-major axis

Explanation : The six orbital elements are used to describe the shape, size and orientation. The semi-major axis (a) is used to determine the size of the orbit. Eccentricity is is determine the orbit shape, and the argument of periapsis determines the orbit’s orientation.

Recently Updated in Spaceflight Mechanics Questions

What kind of trajectory is obtained if the satellite is launched from a place whose latitude is 30 deg

Arc trajectory

Co-axial trajectory

Coplanar trajectory

Non-coplanar trajectory

Correct Answer : Option (D) : Non-coplanar trajectory

Explanation : Coplanar trajectory only occurs when the launch is at a suitable condition where launch latitude matches the moon’s orbital inclination. This is a rare condition which occurs only at Cape Kennedy whose latitude for launch is 28.5 deg. When launches are done at any other location or when the suitable conditions is not met, it results in non-coplanar trajectory.

Which of these is not a constraint on lunar trajectories?

Phase of the moon

Accuracy tolerance

Launch site location

Rotation speed of the earth

Correct Answer : Option (D) : Rotation speed of the earth

Explanation : There are several constraints which carrying out lunar missions. These include-launch site location, accuracy tolerance, limited range of injection conditions, phase of the moon determining the lighting condition, direction of launch from a site.

What is the right ascension of launch point equal to?

Synodic time

Local sidereal time

East longitude

Greenwich sidereal time

Correct Answer : Option (B) : Local sidereal time