213 Deployment System for Three Axis CubeSat Electric Field Instrument  

Dana Turse*, Larry Adams* and Chris Esser* 

Abstract  

To address Heliophysics scientific objectives, CTD is currently developing the deployment system for the CubeSat Electric Field Instrument (CEFI), a 3D vector electric field instrument that can be accommodated  on a CubeSat. CEFI  is enabled by CTD’s deployable composite boom technology that provides  lightweight, stiff, straight, thermally stable booms capable of being stowed within a CubeSat form factor. The boom technology will also provide the CubeSat community with the capability to include one or more deployable booms with lengths greater than 5 meters for future CubeSat missions . CTD recently  demonstrated this technology through the fabrication and testing of prototypes.  

Introduction  

Our present understanding of magnetosphere- ionosphere coupling is limited, partly due to the lack of  broad statistical observations of the 3- dimensional (3D) electric field in the altitude region between 300  and 1000 km. This understanding is of national importance not only because of its intrinsic scientific  worth, but also because it is a necessary step toward developing the ability to measure and forecast the  "space weather" that affects modern technology. Observations from different altitudes and from different  magnetospheric activity levels are required to differenti ate between spatial and temporal variability.  Therefore, the availability of multi -point 3D electric field measurements in this region would greatly  improve our understanding of how energy flows and dissipates in the ionosphere.    The high cost of space acc ess and short satellite lifetimes at low altitudes  make traditional satellites  uneconomical for performing these measurements . Therefore, it is desirable to develop smaller and  lower -cost sensor/satellite systems, such as CubeSats, so that the largest poss ible number of distributed  measurements can be economically made in this region. These science objectives can be met using multiple C ubeSats in Low Earth Orbit  if they each include 3- axis electric field instruments. Therefore, CTD  is developing the CubeSat  Electric Field Instrument (CEFI), a 3D vector electric field instrument that can  be accommodated in less than half of a 6U (10x20x30 cm) CubeSat. This instrument is enabled by CTD’s game changing deployable composite boom technology that provides lightwei ght, stiff, straight, thermally  stable booms capable of being stowed within a CubeSat form factor. This technology will also provide the CubeSat community with the capability to include one or more deployable booms with lengths greater than 5 meters for future CubeSat missions.  

CEFI Overview  

CEFI will be a 3- axis electric field instrument with six rigid booms packaged into half the volume of a 6U  CubeSat . The rigidity of the booms is a key characteristic that enables the instrument to be integrated on  a 3-axis stabilized CubeSat platform . A notional 6U spacecraft is shown in Figure 1 with the instrument in  both the stowed and deployed configurations . The instrument consists of the internal electronics and six  spherical sensors mounted on long rigid graphite composite booms . The opposing sensors can be used  to form three orthogonal dipoles or be measured individually depending on the instrument measurement  mode. The booms are baselined at 2.5- m long, forming a dipole length of 5 m.                                                                  * Composite Technology Development, Inc., Lafayette, C O 

Proceedings of the 43rd Aerospace Mechanisms Symposium, NASA Ames Research Center, May 4-6, 2016