If a new electromagnetic (EM) propulsion technology lives up to its potential, it will revolutionize the capabilities of satellites and future spacecraft. Scientists at the University of Maryland’s Space Power and Propulsion Laboratory (SPPL) are currently working on the Resonant Inductive Near-field Generation System (RINGS), which could reduce the reliance on propellants via a renewable power source. They also are working on a demonstration of wireless power transfer. A finite propellant payload is one of the main limiting factors in terms of how many times a satellite can be repositioned once in space. A renewable, on-board electromagnetic power source, which doesn’t rely on propellants, could greatly extend a satellite’s lifespan and provide greater scientific return.

Essentially, RINGS could enable electromagnetic formation flight (EMFF), which uses locally generated electromagnetic forces to position satellites and spacecraft without the use of propellants. The wireless-power-transfer technology uses EMFF to reposition satellites, providing a means to wirelessly transfer power between spacecraft and power a smaller fleet. Such wireless-power-transfer capability could also provide the flexibility to perform formation control maneuvers, such as the creation of synthetic aperture arrays. Those arrays--a collection of smaller antennas that function as a collective larger antenna--may then be capable of producing higher-resolution images and better-quality data.

RINGS is composed of two units. Each one contains a specially fabricated coil of aluminum wire, which supports an oscillating current to 18 A and is housed within a protective polycarbonate shell. While aluminum was chosen for its low density during the research phase, the systems that are actually implemented will use superconducting wires to increase range and performance.

The system has already achieved a successful demonstration of EMFF in full 6 deg. of freedom. Most recently, RINGS was sent to the International Space Station as part of a payload launched on Japan’s HTV-4 Cargo Ship from the Tanegashima Space Center.. The RINGS project is a collaborative effort between UMD SPPL and partners from the Massachusetts Institute of Technology (MIT) and Aurora Flight Sciences (AFS).