Which of these trajectories makes use of moon's gravity to return it back to earth's trajectory?

Free-trajectory

Slingshot trajectory

Trans-lunar trajectory

Circumlunar trajectory

Correct Answer : Circumlunar trajectory

Explanation : Circumlunar trajectory is a type of free-return trajectory which sends the spacecraft from Earth around far-side of the moon to return it back to the Earth’s orbit using gravity only once the initial trajectory is set. For a circumlunar flight, we need to compute both the perigee condition and condition upon exit from lunar sphere of influence.

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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