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Atmospheric Neutral Density Experiment (ANDE) consists of two microsatellites launched from the Shuttle payload bay will measure the density and composition of the low Earth orbit (LEO) atmosphere while being tracked from the ground. The data will be used to better predict the movement of objects in orbit.

The MAA spherical 50 kilogram (kg) satellite is 48 cm in diameter and constructed from two anodized aluminum hemispheres. The hemispheres were formed by spin-casting aluminum. They were then rough machined, heat treated, machine finished, and finally, anodized. The equator of this sphere was constructed from an engineered polymer material that is a durable, lightweight, low-wear, low-friction plastic that acts as a non-conductive separator between the hemispheres. This allows the satellite's shell to perform as a dipole antenna for the communications system developed at the U.S. Naval Academy.

The communications system is powered by four battery boxes, which gives the satellite an estimated lifetime of about 1.5 years. The payload is split into the two hemispheres, with two battery banks, a communications box, and the laser driver box stacked in a vertical configuration.

The MAA sphere is painted with a pattern of four 90¼ longitudinal segments, alternating bare black anodized aluminum and gloss white paint. The purpose of this paint scheme is two-fold: (1) to provide an easy visual pattern for observing the initial spin rate and orientation; and, (2) to provide a means to determine spin rate and orientation from the polarization return to be observed from the Air Force Maui Optical and Supercomputing (AMOS) facility.

On-board instrumentation for the MAA satellite consists of a set of six CIGS photovoltaic cells that are mounted flush with the surface of the sphere. These light sensors are located at the endpoints of three nearly orthogonal axes and are used for attitude and spin rate determination. Thermistors (thermally-sensitive resistors whose resistance changes with temperature) are placed at several points within the satellite to monitor the temperature of the various components of the satellite. The temperature and photovoltaic voltage values are telemetered to the ground by a "heartbeat" communications system that activates for 2 seconds out of every 20 seconds. If a ground station is detected, the data are transmitted; if not, the system returns to a sleep cycle for another 20 seconds. A set of six laser diodes, also located at the endpoints of three nearly orthogonal axes, are programmed to turn "on" during passes over Maui. These diodes emit light at 810 nm, which will be observed from the AMOS facility.

The arrangement of the MAA and FCal satellites in a lead-trail orbit provides an exceptional set of targets to study drag modeling and its effect on satellite drag. This mission will demonstrate the effectiveness of flying low-cost calibration targets to support DoD and NASA requirements for precision orbit determination and collision avoidance. In addition, data from this mission will be used to improve the scientific understanding of the interaction between a spacecraft and its environment.

Alternate Names

  • Atmospheric Neutral Density Experiment Mock ANDE Active Satellite
  • 29664

Facts in Brief

Launch Date: 2006-12-10
Launch Vehicle: Shuttle
Launch Site: Cape Canaveral, United States
Mass: 50.0 kg

Funding Agencies

  • US Naval Research Laboratory (United States)
  • United States Naval Academy (United States)
  • United States Air Force Academy (United States)
  • US Air Force Research Laboratory (United States)


  • Communications
  • Earth Science
  • Technology Applications

Additional Information

Questions or comments about this spacecraft can be directed to: Coordinated Request and User Support Office.

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