Top image: Artist's conception of a fusion-driven spacecraft. In this image, the crew would reside in the forward-most chamber. Solar panels would harvest energy to initiate the process that creates fusion. Photo Credit: University of Washington via SPACE.com.
Over at SPACE.com, Mike Wall gives some details on a fusion-driven rocket being designed by John Slough and his team of researchers at the University of Washington. Slough's team is 0ne of several currently racing to develop next-generation propulsion systems that could soon replace traditional chemical rockets and clear a human-friendly path to the depths of space. According to one of Slough's team members, their rocket "is probably the most simple and straightforward, lowest-cost fusion propulsion system you can think of":
Such a system could get astronauts to the Red Planet in just 90 days or so, the researchers say. In fact, they're designing their work around a reference mission that lasts a total of 210 days — 83 days for the flight out, 30 days on the Red Planet's surface and a 97-day journey back to Earth.
Harnessing the power of nuclear fusion— the same process that fuels the sun and gives hydrogen bombs their enormous destructive potential — would make such speedy trips possible, team members say.
In their engine, bubbles of plasma — made from deuterium and tritium, "heavy" isotopes of hydrogen — would be injected into a chamber, where a magnetic field would collapse metal rings around them. This would briefly compress the bubbles into a fusion state, releasing energy that would vaporize and ionize the metal. The metal would then be accelerated out the back of the spacecraft through a nozzle, creating thrust.
A lot of work will be required to bring this concept to reality, but there's no reason to think that it won't work, the researchers say.
"This is probably the most simple and straightforward, lowest-cost fusion propulsion system you can think of," team member Anthony Pancotti, of the space-propulsion company MSNW, said in September during a presentation with NASA's Future In-Space Operations working group.
"The fundamental physics have been proven in the laboratory with hardware, and fusion yields — neutrons — have been produced," he added. "So what I'm talking about is building a device with known physics and with a proven method."
As Slough points out, humanity's prospects of exploring trans-lunar space with existing rocket fuels are basically zilch. The limits of our current engineering (not to mention the limits of the human psyche) demand it. If we want to explore much beyond the moon, we'll need a new paradigm in propulsion technologies. Is nuclear fusion (or fission) the way forward?