...we don't have a way to ignite and sustain that reaction without needing to input more energy than we can extract in a usable fashion from the fusion that occurs
Bollocks. The break-even point was passed this year. Sure it's not reached a point of economy-of-scale, but it was a critical change in the fusion story.
Well, there's a big difference between saying something won't ever happen because it's never happened yet, and saying that a claim that you've done something is presumptively not credible unless you can meet certain stadnards of proof.
ISTM that panicky mothers would *love* this...
Check out this graph.
The nuimbers of prisoners has not declined significantly since 2009. This doesn't mean the bubble hasn't burst, the nature of the bubble resists bursting. People can leave the housing market, but prisoners can't leave the prison market.
Still, anyone who invested big-time in prisons back in 2008 or so on the basis of 30 years of exponential prison population growth was just stupid. We were approaching 1% of the Amercian population incarcerated, how much higher did they expect that to go?
I have no sympathy with a town that bet its financial future on prisons while its schools rate minimally acceptable.
Oh please, be serious. It's humans running the robots who make the decisions. The only benefit a human on Mars has is latency. But that's a really silly benefit, given that there's no urgency to get the data and just travel there takes months and the limiting factor on how much data you'll collect overall is how long your scientific equipment lasts. And no, an astronaut on Mars isn't going to be repairing a broken mass spectrometer or the like, it's a silly concept. And it'd, as noted, be orders of magnitude cheaper just to send a second robot.
I am correct, look it up if you don't believe me. The energy is primarily in the form of fission fragments. And no, chain reactions work exactly the same, the neutronicity doesn't vary. You're confusing fission fragments and neutrons.
I don't have anything backwards. As far as solar sails go, interplanetary travel is short distance.
The thrust is really, really, really tiny, for really, really, really huge sails.
I totally disagree. A dusty fission fragment reactor has been demonstrated using a non-nuclear substitute fuel, which demonstrated proper containment and thermal management. And modelling shows that such a configuration should produce a collimated fission fragment beam. So what's so grossly impractical? Have you come across a paper indicating that it's impractical? Because I sure haven't.
My previous comments apply to NEP
I'm not talking about NEP. I'm talking about generating a RF plasma and funnelling it through a nozzle, like in VASIMR, but with primary heating being from an IR nuclear lightbulb. And even if I wasn't, commentary on conventional nuclear reactors vs. solar is inapplicable when one is talking about totally different type of reactor.
Hmm... I'm not sure what you're thinking about doing with CAD, but a Sim that handles real inorganic (and potentially simple organic) chemistry and materials properties could be incredible for enabling the crowd-sourcing of simplifying the tech chains of refining and production, which on earth are just ridiculously long and totally impractical to just migrate to Mars. The users would be given a realistic distribution of raw Martian minerals, and would have to feed the 3d printers / molders / CNC machines / lithography / robotic assembly that makes products. These products would include a (long) fixed set of needs to keep colonists alive and comfortable, as well as spare parts for your refining / mining equipment and the manufacturing hardware's equipment. Users could then try to produce as much of a colony's needs as possible with as little imported hardware as possible.
Simulating wear and corrosion on the refining, transport, and mining hardware would be a must. I think requiring the users to design the full details of the 3d printing and other manufacturing hardware would be overkill, but they should be able to choose what materials different "major parts" for them are made out of and what they want to supply as raw materials, which would affect wear / corrosion rates / efficiency / etc. Game consultants should include a wide range of people with real-world experience in different industries to make sure it's realistic, and the game should be launched with a variety of real-world pieces of Earth mining and refining hardware so that new players have something to start out with and tweak (albeit starting out heavily reliant on imports from Earth). As each person designs a new piece of hardware and tries it out, it should be saved to a global database, along with a history of what it's been taking in (raw materials, parts, etc) and producing as an outputs. Others could then search through the global database for equipment that does a function that they need to incorporate into their hardware.
The game could run in a MMO mode or single-user sandbox mode. In MMO mode there would be multiple users each with their own mine, refining center, manufacturing center, or whatever they want to build) on Mars, while in single-user mode a user would have their own whole planet to play with on their own. Once they get a production line running they can dispatch transport to carry materials or goods to where they're needed, there can be mishaps along the way, etc - all of the elements of your typical enjoyable Sim game - except with real-world chemistry and mechanical properties underlying key aspects. The victory condition would be total manufacturing indepence from Earth. The loss condition would be overstraining Earth's ability to supply you, leading to shortages and colonist deaths.
I think something like that could, if well designed, be both potentially fun for users and useful for engineers designing real-world infrastructure.
Great! Now you just need to invent an actually functional confinement method for the absurdly-hot gaseous/plasma nuclear fuel to stop it from destroying its containment vessel or leaking out its fuel in short order. And while you're at it, you should probably go ahead and invent a way to stop the quartz / fused silica bulb from undergoing blackening when exposed to a neutron flux, something it's so prone to doing that people deliberately expose quartz to nuclear reactors to make opaque black quartz for jewelry. And of course, a way to start the whole thing, a process that's been so problematic that they've been investigating bombardment by sizeable amounts of bloody antimatter as a potential solution.
Easy as pie, surely! Riiight around the corner.
What isotope are you thinking of as fuel? Unicorn-235?
The shuttle wasn't thrown away, nor were the boosters - only the (rather simple) ET. How did that work out, price-wise?
It's simply not fair to pretend that launch costs are a minor issue. They are the limiting factor, and progress in reducing costs has been lethargic over the past decades. "in orbit operations" are expensive precisely because launch costs are so high. Bargain basement, pay-out-the-nose-for-insurance launch rates are $4-5k a kilogram. More typical Russian rates are about $6-7k, while typical US and European rates run about $10k. And that's for large payloads, for small payloads expect in the (very) rough ballpark of $20k. How do you expect to live affordably in space if launch costs are even within an order of magnitude of that?
That's not to say that rockets fundamentally can't provide cheap access to space. But today's rockets certainly can't.
Presently working or theoretical? If you want "presently working", then that would defeat the point of asking for suggestions, would it not? If you want theoretical, there's tons. I kind of like the Launch Loop concept - sort of like a space elevator except that it doesn't require unobtanium, avoids or reduces the countless other problems with space elevators (micrometeorite damage, oscillation modes, power transfer, lightning and ionospheric discharge, and about 50 other things), and it gives you much more ideal/customizable orbital momentum, plus is 1-2 orders of magnitude more energy efficient at lifting cargo (space elevator climbers have to rely on beamed power, there's no practical way to send it through the cable, and beamed power over great distances where one receiver is only a few square meters at best is very low efficiency) AND offers a far higher launch rate.
Earth-based space elevators, the stuff of sci-fi nerd dreams, really are an awful solution when you start looking at the details. There's far better solutions out there.
So you think that money is the root of all evil. Have you ever asked what is the root of money? -- Ayn Rand
