ORBITAL MECHANICS FOR ENGINEERING
STUDENTS ACTUAL TEST QUESTIONS WITH
COMPLETE ANSWER KEY
●● Kepler has two different sets of laws of orbital motion. One set
applies to planets orbiting the sun, and the other set applies to man-made
satellites orbiting the Earth
Answer: False
●● To make the picture more circular, you should move focii A and B
closer together or farther apart?
Answer: Closer together
●● A circular orbit has an apogee roughly twice the altitude of its
perigee
Answer: False
●● Closer
Answer: Perigee
●● Farther
Answer: Apogee
,●● Both size (semi-major axis and/or altitude) and eccentricity play an
important role in determining the period of an orbit
Answer: False
●● The voyager 1 spacecraft was launched in 1977 to explore the solar
system and beyond. In 2008, it was entering the region between our
solar system and interstellar space known as the heliosheath. It is the
furthest manmade object from the earth and is continuing on its journey
into the unknown. Based on what you have learned about orbital
elements, the eccentricity of Voyager 1 is greater than 1.
Answer: True
●● Who developed the keplerian element set which describes the orbital
parameters of satellites' orbits?
Answer: Kepler
●● What is the projection of a satellites orbit onto the earth, represented
in a 2d map?
Answer: Ground trace
●● What two details of satllites orbit can be determined from examining
a ground trace?
Answer: Period and inclination
,●● A satellite designed to take images to monitor the polar ice caps
could have an inclination of 35,75, or 90 degrees?
Answer: 90
●● A satellite crosses the equator in a northerly direction at 0 degrees
longitude. On its next northerly pass over the equator it crosses at 23
degrees west longitude. How long did it take this satellite to complete
one orbit?
Answer: 92 minutes
●● Eccentricity
Answer: A measure of how circular or elliptical an orbit is (0 - circular,
smaller = more elliptical)
●● Inclination
Answer: The tilt of the orbit relative to the equator
●● Semi-major axis
Answer: Describes the size of an orbit. For circular orbits, altitude is
often used in place of this term
●● Which orbital parameter must use a reference point in space, because
an earth based point will move as the earth rotates.
Answer: Right ascension of the ascending node
, ●● Which of the following orbital parameters describe the size and
shape of the orbit?
Answer: Semi-major axis and eccentricity
●● The value of which orbital parameter is 0 when the satellite is at its
perigee point and 180 when the satellite is at apogee
Answer: True anomaly
●● Which of the following missions would probably use a polar orbit?
Answer: Satellite collecting data on air quality on all continents
●● A geostationary satellite is called such because it is a satellite that
doesn't move
Answer: False
●● There is only one specified altitude for LEO satellites
Answer: False
●● Why is there a ring of satellites around the earths equator roughly
22000miles away from the earth?
Answer: Geosynchronous orbit
STUDENTS ACTUAL TEST QUESTIONS WITH
COMPLETE ANSWER KEY
●● Kepler has two different sets of laws of orbital motion. One set
applies to planets orbiting the sun, and the other set applies to man-made
satellites orbiting the Earth
Answer: False
●● To make the picture more circular, you should move focii A and B
closer together or farther apart?
Answer: Closer together
●● A circular orbit has an apogee roughly twice the altitude of its
perigee
Answer: False
●● Closer
Answer: Perigee
●● Farther
Answer: Apogee
,●● Both size (semi-major axis and/or altitude) and eccentricity play an
important role in determining the period of an orbit
Answer: False
●● The voyager 1 spacecraft was launched in 1977 to explore the solar
system and beyond. In 2008, it was entering the region between our
solar system and interstellar space known as the heliosheath. It is the
furthest manmade object from the earth and is continuing on its journey
into the unknown. Based on what you have learned about orbital
elements, the eccentricity of Voyager 1 is greater than 1.
Answer: True
●● Who developed the keplerian element set which describes the orbital
parameters of satellites' orbits?
Answer: Kepler
●● What is the projection of a satellites orbit onto the earth, represented
in a 2d map?
Answer: Ground trace
●● What two details of satllites orbit can be determined from examining
a ground trace?
Answer: Period and inclination
,●● A satellite designed to take images to monitor the polar ice caps
could have an inclination of 35,75, or 90 degrees?
Answer: 90
●● A satellite crosses the equator in a northerly direction at 0 degrees
longitude. On its next northerly pass over the equator it crosses at 23
degrees west longitude. How long did it take this satellite to complete
one orbit?
Answer: 92 minutes
●● Eccentricity
Answer: A measure of how circular or elliptical an orbit is (0 - circular,
smaller = more elliptical)
●● Inclination
Answer: The tilt of the orbit relative to the equator
●● Semi-major axis
Answer: Describes the size of an orbit. For circular orbits, altitude is
often used in place of this term
●● Which orbital parameter must use a reference point in space, because
an earth based point will move as the earth rotates.
Answer: Right ascension of the ascending node
, ●● Which of the following orbital parameters describe the size and
shape of the orbit?
Answer: Semi-major axis and eccentricity
●● The value of which orbital parameter is 0 when the satellite is at its
perigee point and 180 when the satellite is at apogee
Answer: True anomaly
●● Which of the following missions would probably use a polar orbit?
Answer: Satellite collecting data on air quality on all continents
●● A geostationary satellite is called such because it is a satellite that
doesn't move
Answer: False
●● There is only one specified altitude for LEO satellites
Answer: False
●● Why is there a ring of satellites around the earths equator roughly
22000miles away from the earth?
Answer: Geosynchronous orbit
