© 2020 Project Lead The Way, Inc. Aerospace Engineering Activity 3.2.5 Orbital Mechanics Modeling – Page 1 Activity 3.2.5 Orbital Mechanics Modeling Introduction Aerospace engineers design satellite orbits to suit the unique requirements of the mission. The orbit is described with six parameters to cover an area on the ground aligned with the mission. In this activity you will apply your knowledge of orbital mechanics to describe the orbit of a satellite based on its ground trace. You will also use Analytical Graphics, Inc. (AGI) Orbit Tuner application within the Satellite Tool Kit s oftware to adjust the orbit of a satellite to achieve a mission objective. The inclination of an orbit can be obtained simply by looking at the ground trace. The inclination of the satellite in degrees is equal to the northern and southern limits of the ground trace in degrees latitude. To determine a satellite’s orbital period, follow the five steps listed below. • Recall that the orbit of a satellite remains fixed in space, and the Earth rotates underneath it. • The westward regression of the ground trace is due to the rotation of the Earth. • Determine how many minutes it takes for the Earth to rotate one degree: degmin0.4deg360min440,1
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rotationrotation • Determine how many degrees per pass the satellite’s orbit regresses on consecutive orbits (equatorial crossing is a common reference point). • How long did it take the Earth to rotate this many degrees? Multiply the number of degrees (at equatorial crossing) by 4.0 minutes per degree. This is the orbital time period of the satellite (units in minutes). © 2020 Project Lead The Way, Inc. Aerospace Engineering Activity 3.2.5 Orbital Mechanics Modeling – Page 2 Proced ure 1. Determine the inclination and period of the satellite which produced the ground trace below. Show all calculations. Inclination: 78 deg Period: 160deg 2. Determine the inclination and period of the satellite which produced the ground trace below. Show all calculations.
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rotationrotation • Determine how many degrees per pass the satellite’s orbit regresses on consecutive orbits (equatorial crossing is a common reference point). • How long did it take the Earth to rotate this many degrees? Multiply the number of degrees (at equatorial crossing) by 4.0 minutes per degree. This is the orbital time period of the satellite (units in minutes). © 2020 Project Lead The Way, Inc. Aerospace Engineering Activity 3.2.5 Orbital Mechanics Modeling – Page 2 Proced ure 1. Determine the inclination and period of the satellite which produced the ground trace below. Show all calculations. Inclination: 78 deg Period: 160deg 2. Determine the inclination and period of the satellite which produced the ground trace below. Show all calculations.
