Department of Defense Synchronized Position, Hold, Engage, Reorient, Experimental Satellites-RINGS (DOD SPHERES-RINGS) - 03.04.14
ISS Science for Everyone
Science Objectives for Everyone
The Department of Defense Synchronized Position, Hold, Engage, Reorient, Experimental Satellites-RINGS (DOD SPHERES-RINGS) investigation uses the SPHERES facility and is designed to demonstrate and test, in a complex environment, enhanced technologies and techniques related to micro electromagnetic formation flight (EMFF) and wireless inductive power transfer. By advancing the knowledge base with regards to inter-satellite attitude control and wireless power transfer, future systems can expect enhanced attitude control performance between separate satellites and potentially the ability to efficiently transfer power at a distance, possibly alleviating the need for alternate or expendable (i.e., batteries) power sources.
Science Results for Everyone
University of Maryland, College Park, MD, United States
Aurora Flight Sciences Corporation, Cambridge, MA, United States
Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)
National Laboratory - Department of Defense (NL-DoD)
ISS Expedition Duration
March 2013 - September 2014
Previous ISS Missions
- The DOD SPHERES-RINGS investigation tests hardware and software developed to enable relative station-keeping, maneuvering, and attitude control between two SPHERES facility satellites using steerable electromagnetic dipoles (i.e., magnetic field pointing using orthogonal electromagnetic coils) at a distance on the order of decimeters to a few meters.
- Another goal of this investigation is to demonstrate wireless power transfer through resonant inductive coupling (i.e., the interaction of an oscillating magnetic field between two capacitively loaded inductors (a tuned circuit), using the same hardware developed for EMFF. For this investigation, the SPHERES facility satellites onboard the International Space Station (ISS) are used to demonstrate the use of electromagnetic coils to maneuver individual SPHERES with respect to one another. By controlling the dipoles, attractive, repulsive, and shear forces can be generated. Using the DOD SPHERES-RINGS hardware, software algorithms are created to produce active safety maneuvers to avoid cooperative and uncooperative spacecraft collisions. Using the same coils in the DOD SPHERES-RINGS investigation, the software demonstrates inductive wireless power transfer, where one SPHERES beams power to another SPHERES via resonant inductive coupling.
- The DOD SPHERES-RINGS investigation is the first demonstration of electromagnetic formation flight in microgravity, as well as the first demonstration of wireless power transfer in space. This effort builds on work previously performed for DARPA’s System F6 program, where the Massachusetts Institute of Technology, the University of Maryland, and Aurora Flight Sciences investigated the feasibility of using the same high temperature superconducting coils to perform both electromagnetic formation flight and wireless power transfer.
The SPHERES facility satellites onboard ISS provide the a unique low risk, low cost, long duration microgravity research facility capable of supporting iterative, quick reaction testing of technologies in support of DoD and NASA missions. Under the auspices of the ISS-Hosted SPHERES Integrated Research Experimentation (InSPIRE) program, the DOD SPHERES-RINGS investigation significantly increases the scope of the SPHERES facility by adding hardware and developing new algorithms to execute investigations and tests of new critical technologies.
The DOD SPHERES-RINGS investigation hardware and algorithms were developed to enable autonomous propellant-free, plume-free satellite cluster maintenance. The inductive wireless power transfer experiment aids in establishing the hardware necessary for future wireless powering of space robotic, sensor and enhanced communications systems.
The DOD SPHERES-RINGS investigation uses the SPHERES facility which consists of three self-contained satellites (i.e., SPHERES). Each satellite is an 18-sided polyhedron that is 0.2 meter in diameter and weighs 3.5 kilograms. Individual satellites contain an internal propulsion system, power, avionics, software, communications, and metrology subsystems. The propulsion system uses carbon dioxide (CO2), which is expelled through the cold gas thrusters. SPHERES satellites are powered by AA batteries.
DOD SPHERES-RINGS unique hardware consists of two RINGS Assemblies each consisting of resonant coils, coil housing with fans, power electronics/batteries and RINGS/SPHERES support structure hardware. Each RINGS Assembly has a diameter of 77 cm with a height of 13.5 cm and weighs 8.9 kilograms. Each RINGS Assembly will be powered by two COTS DeWalt DC9180 ?pod-style? Lithium Ion 18V 2.0 Ah batteries. 24 DeWalt batteries will be flown to support the operations of DOD SPHERES-RINGS. Two dual battery chargers will also be flown to support recharging of the DeWalt batteries. Each battery charger is 45.5cm X 25.2cm X 17.3cm and weighs 10.5 kilograms.
As a test bed, the SPHERES facility serves to develop and test new technologies which, in turn, become part of future DoD and NASA missions. The DOD SPHERES-RINGS investigation hardware and algorithms were developed to enable autonomous propellant-free, plume-free satellite cluster maintenance. By advancing the knowledge base with regards to inter-satellite attitude control and wireless power transfer, future systems can expect enhanced attitude control performance between separate satellites and potentially the ability to efficiently transfer power at a distance, possibly alleviating the need for alternate or expendable (i.e., batteries) power sources. The inductive wireless power transfer experiment aids in establishing the hardware necessary for future wireless powering of space robotic, sensor and enhanced communications systems.
The inductive wireless power transfer experiment aids in establishing the hardware necessary for future wireless powering of urban robotics and sensor systems as well as enhanced underwater communications systems.
The SPHERES facility is allocated a number of test sessions per ISS Increment. Four test sessions will be utilized by DOD SPHERES-RINGS as the facility user. As the facility lead, NASA Ames will determine specific test session scheduling based on ongoing planning and research results.
A typical DOD SPHERES-RINGS test session will consist of:
- Uplink algorithms one week before the test session.
- Charge 24 batteries prior to each test session.
- Unstow and configure SPHERES facility satellites and work area.
- Attach and configure the DOD SPHERES-RINGS hardware to the SPHERES satellites.
- Load algorithms onto the SPHERES through the communication system.
- Cross-link of real-time data to the ISS ELC laptop.
- Downlink of the data for post-session assessment.
MIT Space Systems Laboratory
SPHERES Facility-Single Unit
+ View Larger Image
RINGS Conceptual Image
+ View Larger Image