Spacecraft Design Fundamentals 29.06

At which point of an elliptical orbit is a spacecraft at its lowest velocity?

• Periapsis

• First point of Aries

• On the semi-minor axis

• Apoapsis 

Which orbital element describes the orbital shape:

• Eccentricity

• True anomaly

• Semi-Major Axis

• RAAN

How does the groundtracks of a perfect GEO and LEO polar orbit look like respectively?

• Straight, sinusoidal

• Sinusoidal, Co-Sinusoidal

• Point, Sinusoidal

• Closed eight, Co-sinusoidal

In which orbit GNSS satellites like GPS or Galileo are positioned?

• GEO

• LEO

• MEO

• All of them

What is the inclination of the satellite with the following groundtrack? Can this groundtrack most likely cover more than 90% landmass of Greenland?

• 55°, Yes!

• 65°, No!

• 60°, Yes!

• Polar orbit, Yes!

___(1)___ maneuver a requires continuous thrust in order to increase the altitude of a spacecraft? And ___(2)___ maneuver typically is the most efficient orbital transfer?

• (1) Hohmann Transfer
  (2) Bi- elliptical Transfer

• (1) Spiraling
  (2) Hohmann Transfer

• (1) Gravity Assist
  (2) Bi- elliptical Transfer

• (1) Bi- elliptical Transfer
  (2) Hohmann Transfer

For which Mission Gravity Assist Maneuvers were performed?

• Galileo

• MOVE-II

• Voyager 1 and 2

• FSSCAT

What is the purpose of the Hohmann maneuver in space travel?

• To change the inclination of an orbit.

• To change the RAAN of the orbit.

• To perform a rendezvous with another spacecraft.

• To transfer between two different circular orbits.

During a Hohmann maneuver, at which points of the orbit are velocity changes typically performed?

• At the periapsis and apoapsis.

• At the ascending node and descending node.

• Both at the periapsis

• At the points of closest approach and farthest distance from the target.

What is the purpose of magnetorquers in ADCS?

• Measuring magnetic fields in space

• Generating electrical power

• Communicating with other spacecraft

• Applying torque to control the spacecraft's attitude