Human travel to Mars has long been the unachievable dangling carrot for space programs. Now, astronauts could be a step closer to our nearest planetary neighbor through a unique manipulation of nuclear fusion, the same energy that powers the sun and stars. University of Washington researchers and scientists at a Redmond-based space-propulsion company are building components of a fusion-powered rocket aimed to clear many of the hurdles that block deep space travel, including long times in transit, exorbitant costs and health risks. '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 project is funded through NASA's Innovative Advanced Concepts Program. Slough and his team from MSNW, of which he is president, presented their mission analysis for a trip to Mars, along with detailed computer modeling and initial experimental results at a NASA symposium. Their project was awarded a second round of funding after being selected from more than 700 proposals. NASA estimates a round-trip human expedition to Mars would take more than four years using current technology, with launch costs alone exceeding $12 billion due to the sheer volume of chemical rocket fuel required. Slough and his team have published papers calculating the potential for 30- and 90-day expeditions to Mars using a rocket powered by fusion, making deep-space travel significantly more practical and less costly. Slough and his colleagues at MSNW have demonstrated successful lab tests of all portions of the process. The research team developed a type of plasma encased in its own magnetic field; nuclear fusion occurs when this plasma is compressed to high pressure with a magnetic field. Only a small amount of fusion is needed to power a rocket—a small grain of sand of this material has the same energy content as 1 gallon of rocket fuel. To power a rocket, a powerful magnetic field causes large metal rings to implode around the plasma, compressing it to a fusion state. The converging rings merge to form a shell that ignites fusion for a few microseconds. The energy released quickly heats and ionizes the shell, and this super-heated, ionized metal is ejected out of the rocket nozzle at high velocity. The process repeats every minute or so to propel the spacecraft. The UW-MSNW team successfully demonstrated the metal-crushing process in the UW Plasma Dynamics Laboratory in Redmond, using a collapsed, fist-sized aluminum ring as proof of concept. The laboratory is filled wall-to-wall with blue energy-storage capacitors connected to a giant magnet. When triggered, the capacitors deliver 1 million amps of electricity for a fraction of a second to compress the metal ring. In space travel, lithium metal would serve as the crushing rings, though aluminum is functionally equivalent for laboratory testing. Addressing potential safety concerns, Slough noted that fusion energy for powering a rocket is reduced by a factor of 1 billion compared to a hydrogen bomb, rendering it incapable of creating a massive explosion, while a strong magnetic field contains the fuel and guides it safely away from the spacecraft. Research partners include Anthony Pancotti, David Kirtley, and George Votroubek of MSNW, along with Christopher Pihl and Michael Pfaff of the University of Washington.