At which position of the moon does the eclipse occur?

When moon is at periapsis

When moon is at apoapsis

When moon is at either side of the equator

When moon is at the nodal crossing

Correct Answer : When moon is at the nodal crossing

Explanation : When the moon is at the either nodal crossing point eclipse occurs. The node where the moon moves from south to north is called ascending node and the node where the moon moves from north to south is known as descending node. Eclipse occurs only a these two points because only in this case the sun, moon and earth are aligned.

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