University of Washington researchers and scientists at a Redmond-based space-propulsion company are currently building components of a fusion-powered spacecraft, which could enable astronauts to travel to Mars within weeks instead of months, at speeds considerably faster than feasible until now. The current travel speeds using fuel rockets make Mars travel a journey of half a year for one way but the new fusion technology being tested by researchers at the University of Washington promises that in 30 to 90 days.

The lab tests have proven to be successful on each part of the process and the scientists are now planning to combine the sections into a one final and overall test. While such a pulsed-fusion device would actually consume energy in the form of electricity (and not produce, like terrestrial fusion power devices are trying to achieve), it would be a very efficient method to drive a spacecraft, since the ratio of impulse to fuel mass is much higher than with conventional chemical engines. It is also superior to ion-drives, which use electrical energy to accelerate the fuel used to generate the impulse. In practice, the fusion material used as consumable, ejected fuel would have a mass of kilograms instead of tons for example, a factor of 1000 less than rocket fuel -- the exact numbers will depend on whatever final design may be implemented.

“Using existing rocket fuels, it’s nearly impossible for humans to explore much beyond Earth,” said lead researcher John Slough, a UW research associate professor of aeronautics and astronautics. “We are hoping to give us a much more powerful source of energy in space that could eventually lead to making interplanetary travel commonplace.”

The team claims to have developed a technology using a special type of plasma that will be encased in a magnetic field. When the plasma is compressed with high pressure by the magnetic field, nuclear fusion takes place.

The process has successfully been tested, according to the researchers, and they plan on having the first full test to be done by the end of this summer.

In practice the powerful magnetic field surrounding metal rings which contain the plasma causes them to implode and compress to the point of fusion. The process takes only a few microseconds, but that will be enough to release sufficient heat and ionize the rings that form a shell around the plasma. The super-heated ionized metal, in turn, ejects out from the rocket at a high velocity pushing the rocket forward. Repeating the process in intervals of about 30 seconds or more can propel a spaceship.

The research was funded by NASA in hopes that the technology would ultimately replace rocket fuel and yield much faster spacecrafts that ever built before. Scientist say that just a grain size of the material that forms the plasma can equal liters of rocket fuel. The total mass of a spacecraft, including the required fuel, could thus become considerably smaller, making deep space travel much more cost effective.