Fusion Rocket Could Take Us To Mars 171
New submitter imikem writes "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 research team has developed a type of plasma that is encased in its own magnetic field. Nuclear fusion occurs when this plasma is compressed to high pressure with a magnetic field. The team has successfully tested this technique in the lab. 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.'"
Re:nuclear fusion? (Score:5, Insightful)
And if the fuels take more energy to prepare than they yield when reacted(tritium is one such fuel), then they're not very useful for energy production, but very useful for energy storage.
Re:Yuh huh (Score:5, Insightful)
There are a few small details to deal with regarding both potential technologies.
Except we know how to create uncontrolled fusion, and a fusion rocket is closer to a hydrogen bomb than a fusion reactor. You're just trying to make fusion happen and throw the resulting plasma out the back, not keep the plasma in one place and generate power from it.
Re:nuclear fusion? (Score:5, Insightful)
We've had nuclear fusion working for over sixty years now. [wikipedia.org] The trick has been containing it in a reactor for power generation. A fusion rocket might be easier to pull off--that's essentially just a semi-contained and directed H-bomb.
Re:nuclear fusion? (Score:5, Insightful)
This. It's all about specific impulse in space travel - which is a very separate concept to net energy production. There's no problem spending a lot of energy making rocket fuels on Earth, when the big cost multiplier is launch mass.
Re:Required electricity (Score:2, Insightful)
Their stated cycle time is 1 minute. Article says they fire for a "fraction of a second" to compress the metal rings, so the peak power generation needed would be 2-3 orders of magnitude lower than the instantaenous power usage. Small scale fission reactor like the sort on a nuclear submarine would do the trick. Or a radioisotope thermal generator: http://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator
Re:Yuh huh (Score:5, Insightful)
Lets not forget that the objective of the rocket is to move you, not generate usable energy. You don't necessarily have to have a net+ for this to be useful.
Think of it as a super high density fuel that just takes a lot of energy on the ground to process.
Re:Yuh huh (Score:3, Insightful)
You need plenty of neutron shielding for fusion. But the advantage of having a spacecraft over a power plant is that you can use distance, by putting it on the end of a long structure, and that you won't care what the neutrons will do to the shielding and equipment on timescales longer than the mission.
Re:We already had this ability in the 1960's (Score:4, Insightful)
I went online looking to debunk this, but frankly its essentially true.
Some further sad facts: In all of history there have been 12 human beings to set foot on another planet [wikipedia.org]. The youngest of them is now 77. Most of them are still alive (probably thanks to the extreme physical fitness required of astronauts), but the day is not too far off when they start dying, and we will be left with no living people who have visited another planet. Most US citizens were not born yet when this was going on.
Space exploration is not something we are actively doing, but part of our history, joining its place alongside the Civil War and Lewis and Clark as "things to bore kids with in US History". If we tried doing it again, we've lost so much capability that it would probably take longer to accomplish, and cost more. We might as well post the poem Ozymandias next to our old Apollo artifacts in the museums:
I met a traveller from an antique land Who said: Two vast and trunkless legs of stone Stand in the desart. Near them, on the sand, Half sunk, a shattered visage lies, whose frown, And wrinkled lip, and sneer of cold command, Tell that its sculptor well those passions read Which yet survive, stamped on these lifeless things, The hand that mocked them and the heart that fed: And on the pedestal these words appear: "My name is Ozymandias, king of kings: Look on my works, ye Mighty, and despair!" Nothing beside remains. Round the decay Of that colossal wreck, boundless and bare The lone and level sands stretch far away
Re:Yuh huh (Score:3, Insightful)
All of the fusion projects that I'm aware of are not only heavy, they're also delicate, and require lots of skilled technical attention.
All of the ones I've worked on were quite robust and solid for the basic structure, as they basic plasma is created and managed with not much more than just a large vacuum vessel, magnets and some power supplies or capacitor banks. This is to the point no one would bother with ladders half the time, because the large bolts and plates on the vacuum vessel turned it into essentially a giant jungle gym that let you get to wherever you needed to on the machine. What tended to be really fragile on the other hand were a lot of the diagnostics, especially stuff like precision optics for spectroscopy or laser based diagnostics, imaging diagnostics, x-ray diagnostics, probes that were stuck into the plasma and shielded with ceramics. But an operating machine would not need 90+% of the diagnostics, and can probably get by on things like magnetic diagnostics that can be made rock solid. I think you could probably go at some of the machines with a sledgehammer, and as long as you avoided the windows on the vacuum vessel and the diagnostics, it would take you a while to do any actual damage.
About the only exception might be some of the heating techniques being used, although those are mostly only relevant to getting steady state reactors going. And those consist of things like high power RF, which the military has some experience with making resilient, and things like neutral beams which would be on par with ion engines that we've already tested in space.
And from your other comment:
Even if ground based fusion reactors turn out to be cheap and simple in the near term, I have severe doubts about thier suitablitity for powering a spaceship until a LOT more development is done.
Assuming there is a demand and hence money for development, I would expect fusion engines to be developed long before ground based fusion reactors are made practical. There are much fewer constraints or much looser constraints for using fusion as propulsion than as a primary source of energy. If you view it as a process for converting electricity into propulsion, you can get by with a lot less efficiency than something that is trying to produce electricity through inefficiency conversion and additionally kept itself going. Because you don't have to worry about contaminating your environment, you have a lot more flexibility and choice in construction materials, and don't need designs that are meant to last decades. The only additional constrain would be worry about mass, but then you at least don't need a whole vacuum vessel and all of the vacuum equipment.