As SpaceX continues the testing phase for Starship and enthusiasm spreads for an actual manned flight to Mars, an interesting magnetic rocket concept conceived by physicist Fatima Ebrahimi of the Princeton Plasma Physics Laboratory (PPPL) at the U.S. Department of Energy (DOE) can make. much more cost effective.
The feasibility of safe, durable propulsion systems that will surpass traditional chemical-based rocket engines on deep space travel, not just in our own solar system, but perhaps one day to a distant galaxy beyond the Milky Way is the main thought of astrophysicists.
Once the default acceleration mode for imaginative sci-fi authors and now the preferred positioning engine for NASA scientists and engineers in their satellites, ion thrusters may have greater endurance and are a lot cheaper to operate, but generate a miniscule amount of thrust for acceleration purposes. This isn’t exactly a viable option for a trip to the Red Planet, where hundreds of tons of spacecraft are being moved across the sky.
Ebrahimi’s Princeton team has developed a new concept that uses the same basic cosmic mechanism that helps push solar flares out from our sun. These violent bursts are made up of charged atoms and particles known as plasma, trapped in intense magnetic fields. Their findings were published on the online research site, Journal of Plasma Physics.
To harness this dynamic energy in an effective propulsion system, Ebrahimi focuses on a type of interaction called magnetic reconnection, in which magnetic fields in highly charged plasma environments automatically restructure themselves to come together, separate, and reunite.
The consequences of this cyclic reaction are an impressive powerhouse of kinetic energy, thermal energy and particle acceleration. This phenomenon is not limited to stars, but also occurs in our planet’s atmosphere and Tokamak fusion reactors, such as PPPL’s National Spherical Torus Experiment.
This innovative thruster produces motion by ejecting both plasma particles and magnetic bubbles known as plasmoids, which increase the power to propel.
“Long-distance travel takes months or years because the specific impulse from chemical rocket engines is very low, so it takes time for the craft to get up to speed,” explains Ebrahimi. “But if we make thrusters based on magnetic reconnection, we may be able to complete long-range missions in a shorter time. While other thrusters need heavy gas made from atoms like xenon, you can use any type of gas you want in this concept.”
A magnetic thruster works in ways like modern ion thrusters that are increasingly common on a wide variety of probes and spacecraft. These work by charging a propellant base made up of heavy atoms such as xenon, then introducing an electric field and making them accelerate. In Ebrahmi’s intriguing concept, magnetic fields are recruited for the acceleration command.
Currently, computer simulations derived from PPPL computers and the National Energy Research Scientific Computing Center at Lawrence Berkeley National Laboratory in Berkeley, California, indicate that magnetic reconnection thrusters can theoretically produce exhaust speeds ten times faster than any electrical propulsion system in use today.
“This work is inspired by past fusion work and this is the first time that plasmoids and reconnection have been proposed for space propulsion,” added Ebrahimi. “The next step is to build a prototype!”