Astronauts on the International Space Station (ISS) are testing a new propulsion system … inside the station. While this might seem like the height of recklessness, this particular system doesn’t use rockets or propellants. Developed in the University of Maryland’s Space Power and Propulsion Laboratory, this new electromagnetic propulsion technology called the Resonant Inductive Near-field Generation System (RINGS) uses magnetic fields to move spacecraft as a way to increase service life and make satellite formation flying more practical.
Formation flying is a new field in spaceflight that allows for tackling large jobs without large satellites. By having satellites flying in a coordinated pattern, they can be turned into sensor arrays in the same way as astronomers use separate of telescopes to create one gigantic scope. It’s a technique with a large potential, but suffers from the fact that it requires a lot of propellant to keep the satellites in position. This makes the spacecraft heavier and shortens their working life. The use of rockets also risks the danger of other craft in the formation getting caught in the backwash, and the flash and heat can blind instruments.
Electromagnetic formation flight (EMFF) gets around this propellant problem by turning the satellites in a formation into electromagnets. By using a combination of magnets and reaction wheels, spacecraft in formation can move and change their attitude and even spin without propellant. Satellites can change their polarity to attract or repel one another, turn, or shift their relative positions in any manner that doesn’t require changing the center of gravity for the entire formation.
According to an MIT study [PDF], when EMFF is perfected, it will have a wide number of applications including interferometers, space telescopes where each satellite carries a section of mirror, generating artificial gravity, creating a magnet shield against solar radiation storms, and clearing space debris by using their spin to toss the debris into a safer trajectory. However, there is still a great deal of work to do because EMFF will need superconducting wires, high-velocity reaction wheels, cryogenic cooling, and other critical technologies to be developed before they become practical. …
Rings is a electromagnetic based propulsion system run by MIT Space Systems Laboratory. The experiment utilizes 2 SPHERES vehicles that are places inside the RINGS support structure and interfaced together through the SPHERES expansion port via a ribbon cable.