ORBS: FEMTOSAT SWARMS FOR SPACE SCIENCE APPLICATIONS
Robbie Robertson
Advisor: Dr. Gregory Earle
Department of Aerospace and Ocean Engineering
Virginia Tech, Blacksburg, VA, 24060, USA
Abstract
A femtosatellite, or femtosat, is a satellite with a mass of less than 100 grams. Solar
radiation pressure (SRP) has a relatively significant influence on the orbits of these very small
satellites.1 Groups, or swarms, of orbiting radiation pressure barometer spheres (ORBS) could be
released with identical inertial and magnetic properties, but with different optical coatings to
isolate the effects of SRP on the relative motion of members of a given ORBS swarm. By
cleverly assigning ORBS optical properties and implementing detailed solar radiation pressure
models, ORBS tracking data could be used to estimate important atmospheric and solar
quantities. First, detailed SRP modeling and orbit propagation tools are being developed to
model the relative dynamics of the members of an ORBS swarm. Second, parameter estimation
techniques are being developed to estimate atmospheric and solar parameters using ORBS
tracking data. When complete, this set of modeling tools will enable the simulation ORBS
science missions. These simulations will enable us to assess the viability of ORBS swarms for
various missions. The SRP modeling, orbit propagation, and parameter estimation tools have
been developed individually and applied successfully to other problems as preliminary steps to
modeling ORBS science missions.