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Simulating Satellite Orbits and Atmospheric Drag

Previously Published

Type of Activity:

  • Lab Activity

Brief description of the activity and its strengths:

Students calculate the decay of a satellite orbit due to drag by the Earth's ionosphere under varying solar conditions.



Type and level of course in which you would use this activity:

Undergraduate required course in introductory physics. 

Skills and concepts that students should have mastered before beginning the activity:

Newton's Second Law of Motion applied to circular motion
Potential and kinetic energy
Conservation of mechanical energy
Work-Energy Theorem
Basic Spread Sheet Manipulations

How the activity is situated in its course

This is a review and knowledge-consolidation activity used three quarters of the way though the course. It is also used as a means of introducing space-related, physical effects to future aerospace officers.


The goals of this exercise are to put the laws of large-scale orbital dynamics into a space physics context while introducing numerical and semi-empirical modeling methods. The spreadsheet simulation consists of two linked spreadsheets and their associated plots. One spreadsheet contains density and temperature for the lower 1000 kilometers of the Earth's atmosphere, and the other contains the orbit simulation. A concept map guides students in developing formulations for describing satellite motion in an atmosphere whose density varies exponentially. At the conclusion of the laboratory students produce temporal profiles of altitude, velocity, energy, and drag force on a low-Earthorbiting satellite. A post-laboratory questionnaire focuses student thought on the physics and modeling process.

Lab materials can be found at


Lab materials can be found at

Instructors review the spreadsheet results with each group of students. Students keep working on the spreadsheet until they achieve the correct solution. Students who quickly achieve the correct solution have the opportunity to do additional data-model comparisons with satellites orbits monitored by NASA, the US Air Force and the US Navy.
All students complete a post-laboratory questionnaire that focuses their thought on the physics and modeling process.

Supporting references and/or URLs

Simulating Realistic Satellite Orbits in the Undergraduate Classroom, in the Oct 2005 edition of The Physics Teacher,
D.J. Knipp, E.T. Patterson, A. Franz, and J.H. Head, U.S. Air Force Academy, Colorado Springs, CO; T.A. Summers, U.S. Air Force Academy and Minot AFB; ND, E.L. Zirbel, Boston University, Boston, MA

Digital Object Identifier

Submitted By:

First Name:Delores
Last Name:Knipp
Institution:CU Boulder