Earth's orbital environment includes natural debris from the universe but the addition of man-made debris has changed that environment since the 1957 launch of the 58 cm shiny metal satellite Sputnik I. The information that follows explains the dangerous nature of the increasing amounts of orbital debris and the importance of tracking the debris to formulate plans for its mitigation. The following portions of this lesson allow students to become scientists in understanding how orbital space debris can be tracked using albedo.
If you cannot view the video in YouTube, click here, Space Debris 1957-2016.
The primer by Aerospace Corporation is an excellent resource for learning about orbital debris.
The Albedo Experiment will allow students to collect data on albedo (reflected light) in real-time from models of items that might be found orbiting the earth in LEO (Low Earth Orbit) or beyond. The sections of this activity will guide you in learning about LEO debris, preparing equipment, the use of the Kepler Light Grapher, and the possible models that you might use to perform the experiment.
Albedo is the amount of light that is reflected from a surface. The image below is from "A Blog About the Universe" and illustrates how light from a light source reflects from a surface. In the Experiment noted below, students will use a Control Target to gather data on albedo and compare it to an Experimental Target as the affect of texture, color, etc. on albedo are considered.
The Albedo Experiment can be performed very simply with several sources of error to be expected or can be conducted in a more controlled effort with equipment that will allow students to focus on the data collected. In either situation, the experiment provides students with a forum to collaborate their critical thinking to minimize any difficulties or unwanted variables that may effect their data.
You will need the following materials for the more controlled experiment:
- Computer with camera
- Access to the Kepler Light Grapher: see Light Grapher below
- An Albedo Detector Spinner (instructions and equipment found below in written and video form): The Detector Spinner is an excellent tool, but students may be able to design some other tool to allow their models to revolve in and out of the light source.)
- A light source - this may be a lamp, light bulb, the flashlight app on a device - it should be quite bright and intense
- A darkened room, or a darkened area behind the revolving model.
- A Model Albedo Target to provide and albedo comparison to an Experimental Target. (This may be a model of an asteroid, a potato, or a multi-faceted home-made item that allows practical surfaces for differing light reflection - instructions for the Model Alabedo Target is found below)
- Tape to hold the model in place as it moves
- Instructions for Using the Light Grapher Program
- The ability to save your Albedo Graph for printing or for reporting.
Denise Wright is allowing EIS to use her tutorial video for use of the Light Grapher. Denise uses the Kepler Light Grapher to model how scientists search for exoplanets. In her video, Denise uses a set-up for exoplanet modeling that does not require the use of the Spinner. You may find this approach helpful. Please view her video to understand how to use the Light Grapher.
The files attached will guide you in constructing the apparatus needed for the Albedo Experiment (that will avoid sources of error), constructing a Control Target, using the Light Grapher webcam to produce light curves of your targets, and a Procedure Worksheet to collect and analyze data to direct student data discussion.
The following video (1.41 minutes) shows the revolution of the NSS Enterprise spacecraft model as a light curve is being generated through the Kepler: Light Grapher Detector- see below.
This video provides a step-by-step explanation to guide you in constructing a spinner to detect albedo.
This file is an .swf (shockwave flash) and it can be downloaded to your computer to allow your computer camera to act as a light sensor and produce a light sensitivity graph noting the albedo produced from the object in the camera's target.
You may need to load Shockwave Flash loaded on your computer to download this file.
- Computer with camera
The Academy is delighted you have chosen to participate in the activities listed under 'Detecting Orbital Debris Using Albedo.' We would greatly appreciate feedback on your experience in the hopes of making this course as valuable as possible. Kindly give your thoughts in the short survey and add pictures of your students' products.
-The EIS Academy
You are invited to enter constructive comments, suggestions and experiences that you have encountered using the lessons and activities in the Detecting Orbital Debris Using Albedo.