SWARM-EX: Space Weather Atmospheric Reconfigurable Multiscale Experiment
Georgia Tech’s SSDL is participating in a multi-university CubeSat formation flying mission to address Geospace science questions related to the Earth’s upper atmosphere.
The equatorial thermal anomaly (ETA) and equatorial ionization anomaly (EIA) describe highly-varying temperatures and electron density variations, respectively, at low magnetic latitudes. These anomalies have competing theories of formation and have been previously difficult to empirically analyze due to their processes occurring on timescales less than 90 minutes. Comprised of three 3U Cube Satellites (CubeSats), the SWARM-EX mission will gather plasma and atomic oxygen data to explore the persistence and variabilities of the ETA and EIA. By controlling the relative separation between spacecraft in the formation as it travels through a low-latitude region, measurements can be cross-calibrated to achieve an unprecedented resolution on plasma gradient and density gradient estimates. This will aid in understanding key features of the ETA and EIA while confirming over what timescales these anomalies exhibit changes.
The SWARM-EX formation has various profiles it will exhibit throughout the mission, as shown in Fig. 1 below. “SCI” refers to the science phases of the mission where plasma density and atomic oxygen measurements will be collected. “OGNC” refers to the mission phases where novel orbit guidance, navigation, and control features will be tested with the formation. To maneuver between formation profiles, each spacecraft will have an onboard propulsion system to provide impulsive burns. To ensure formation safety and obtain highly accurate position fixes, each spacecraft will communicate with one another via inter-satellite communication which utilizes UHF.
Fig. 1: Formation profiles in each mission phase for the SWARM-EX Mission.
As a member lab of this mission, SSDL will design, test, and deliver a 3D-printed cold-gas thruster for each of the three CubeSats. Furthermore, SSDL is responsible for the attitude determination and control subsystem (ADCS) of each CubeSat. This includes defining pointing profiles for the mission which satisfy power, science, and GNC requirements, designing reaction wheel and magnetic detumbling controllers which model the vendor-supplied units, and leading the integration and test efforts once hardware is received. As a collaborative effort between six universities, this mission allows SSDL students to work with fellow peers, faculty who serve as subject-matter experts, and others throughout the space industry.