The Atmospheric Neutral Density Experiment (ANDE) Risk Reduction Mission consists of two spherical spacecraft fitted with retro-reflectors for satellite laser ranging (SLR). Scientific objectives of the ANDE missions include monitoring total neutral density along the orbit for improved orbit determination of space objects, monitoring the spin rate and orientation of the spacecraft to better understand in-orbit dynamics, and to provide a test object for polarimetry studies. The mission will provide objects in low Earth orbit with well-determined ballistic coefficients and radar cross-sections for comprehensive atmospheric modeling. Each mission will include a passive and an active spherical spacecraft in a lead-trail orbit configuration. The passive sphere will be tracked with the Space Surveillance Network (SSN) and SLR to study atmospheric drag and in-track total density. The active sphere will have on-board instrumentation to measure atmospheric density and composition. The active sphere will monitor its position relative to the passive sphere to study drag models. The active satellites will communicate on-board data through a system of modulated retro-reflectors (MRR). Mission Objectives: Provide Total Atmospheric Density for Orbit Determination and Collision Avoidance Space to Ground Optical Communication Demo Validate Fundamental Theories on the Calculation of the Drag Coefficient Provide Calibration Object for Radar Fence Upgrade Establish a Method to Validate Neutral Density and Composition Derived from DMSP Sensors. Active Sphere Instrumentation: Modulating Retro-Reflector (MRR) Array Final layout analysis in progress One hemisphere densely populated One hemisphere with single MRR Thermal Control System (± 5 C) Thermal Monitoring System (TMS) ( ≤ 1C) Global Positioning Sensor (GPS) Wind and Temperature Spectrometer (WATS) (1-46 amu) Backup Communications System Photovoltaic Arrays Lithium Ion Batteries Passive Sphere Instrumentation: Retro-Reflector Array 21st December 2006

Measure angle of polarization

Polarizers Malus's Law Brewster Angle Polarization by Reflection and Scattering Why is the sky blue? Why are sunsets red? The sun will set in the lecture hall! View the complete course at: http://ocw.mit.edu/8-02S02 License: Creative Commons BY-NC-SA More information at http://ocw.mit.edu/terms More courses at http://ocw.mit.edu

polarimeter 1. an instrument used to measure the rotation of the plane of polarized light as it passes through a sample of an optically active compound

Shows that a solution of glucose rotates the plane of polarization of light. The home made polarimeter uses a laptop screen as the source for polarized light. Polarized sunglasses are used to analyze the light. The solution of glucose (Karo syrup) is in a can glued to a piece of glass.

The video shows a home made polarimeter with 4 "chambers" made from 4 oz fruit cans glued to a pane of glass. The glass pane is resting on the screen of a laptop computer. The light from the computer screen is polarized. The video was shot through a polarized lens from a pair of sunglasses. The level of light that passes through the lens varies with the light's plan of polarization. When the light entering the lens is at right angles to the direction of polarization for the lens, the light is blocked. (Note that the light from the computer is polarized at a 45 degree angle, so that you can read the screen with your sunglasses on). Light that is parallel to the len's plane fo polarization passes through, and intermediate angles are partially blocked. The 4 chambers contain water or varying amounts of glucose solution (Karo syrup). The glucose solutions rotate the plane of polarization - glucose is an "optically active" molecule. The computer rests on a lazy susan, whcih allows it it spin 360 degrees.