Two Possible Alternatives To Se And Building Large Ships In Orbit

[tercentennial]

I'm currently working on a book that involves a crash course through a new space race and I came up with a few alternatives to some of the classic issues of space elevators and constructing large ships in orbit. I was hopping to get some feed back from everyone as to feasibility and how many years it might be until such technologies might be possible.

 

One A space staircase: Starting with a large launch platform on ground IR lasers pulse large amounts of energy into the bottom of a space craft. This works on the one hand like current beam propulsion proposals but adds in an air tank that separates O2 out of the atmosphere which is later ignited with the heat of the laser to add in an extra burst of thrust once as the craft gets farther away from the base station. In addition to the ground station there would also be at least two large solar powered unmanned balloon stations in atmosphere that the craft would dock with and begin the cycle over again. After the craft left the atmosphere it would meet up with more unmanned space stations in LEO and higher orbits which would replace igniting the air with bouncing the beam of a light sail built in orbit and attached to the craft once it was feasible to do so, with a possible intermediary stage in LEO where the craft used a of a traditional rocket fuel loaded at the station there.

 

Two genetically engineered trees capable of living in the Lagrange points: With a stable habitable station build at on of the Lagrange points built using more traditional construction methods, seeds for trees capable of surviving vacuum would be planted and allowed to grow. The trees would form the basis for the majority or the body of future generations of space ships lowering the requirements for launching construction materials to space to the absolute necessities, IE. Shielding materials and electronics.

 

Feel free to tell me I have no idea what I'm talking about here or to leave your own ideas for simpler alternatives for the big projects most people see in the future of space exploration.

[CraigD]

Welcome to hypography, Andrew  Always a pleasure to be joined by someone working on a SF story! :thumbs_up

 

I'm currently working on a book that involves a crash course through a new space race and I came up with a few alternatives to some of the classic issues of space elevators and constructing large ships in orbit. I was hopping to get some feed back from everyone as to feasibility ...

It’s always good, and rarely too much work, to work out the feasibility of an idea before putting it into fiction. Really, this act is what separates science fiction from fantasy.

 

One A space staircase: Starting with a large launch platform on ground IR lasers pulse large amounts of energy into the bottom of a space craft. This works on the one hand like current beam propulsion proposals but adds in an air tank that separates O2 out of the atmosphere which is later ignited with the heat of the laser to add in an extra burst of thrust once as the craft gets farther away from the base station. In addition to the ground station there would also be at least two large solar powered unmanned balloon stations in atmosphere that the craft would dock with and begin the cycle over again.

I think you may be plagued with the common misconception that increasing the height from which a ship is launched from a more-or-less stationary platform, say from the surface (r = about 637000 m) to the Karman line (r = about 647000 m) gives a big saving in impulse / delta-V requirements. A quick calculation using the formula for escape speed,

 

[math] V_e = \sqrt{\frac{2u}{r}}[/math]

 

, though, shows you that it doesn’t: [imath]\sqrt{\frac{637000}{647000}} \dot= 0.992[/imath], less than a 1% delta-V saving.

 

Getting above the atmosphere does allow your spaceship to avoid energy loss due to air friction, so isn’t meritless, as shown by airdrop spacecraft like the old B-52/X-15, White Knight/Spaceship One, Virgin Galactic’s White Knight/Spaceship Two, and Stratolaunch Systems’s recently much publicized but still-in-concept-phase giant carrier airplane system, but IMHO more promising are systems that take advantage of their passage through the atmosphere to gain speed and oxidizer, such as REL’s engines-nearing-completion-of-proof-of-concept-phase Skylon.

 

A slight nit-pick: you can’t ignite oxygen by heating it. You’ve got to have something that chemically reacts with it, say hydrogen. If you do, only a little heat – a spark – is needed to ignite the mixture. This is how all hydrogen/oxygen rockets, about the most common kind, are powered.

 

Beam propulsion needs something that can expand to provide thrust when heated. O₂ would work, but it’s not ideal, and no easier to collect at high altitudes than any other atmospheric gas. So most beam propulsion systems (none of which are very far along in development) are designed to heat a high-density solid or liquid, or due to its low molecular mass (you can’t get any lower), hydrogen gas from liquid hydrogen.

 

After the craft left the atmosphere it would meet up with more unmanned space stations in LEO and higher orbits which would replace igniting the air with bouncing the beam of a light sail built in orbit and attached to the craft once it was feasible to do so, with a possible intermediary stage in LEO where the craft used a of a traditional rocket fuel loaded at the station there.

I’m a big fan of powered lighsail propulsion, but very mindful of the attenuation cost of having your light source at the bottom of a thick atmosphere like Earth’s. I think powered lighsails are likely the ultimate near-term system for interplanetary and even interstellar spaceflight, but that the light sources will need to be in space.

 

In short, the scheme of gaining altitude in increments is, I think, simply a flawed one, because what you need mostly to reach or escape orbit is speed, not altitude.

 

Two genetically engineered trees capable of living in the Lagrange points: With a stable habitable station build at on of the Lagrange points built using more traditional construction methods, seeds for trees capable of surviving vacuum would be planted and allowed to grow.

The big problem here is that trees don’t create mass out of sunlight – they use sunlight to rearrange mass into more useful forms (eg: water and carbon into sugars). So you’d need not only seeds, but something analogous to dirt and air.

 

A icy body like a comet might be ideal to plant your space trees in, but if you’ve got what it takes to park a comet at a Lagrange point, you’re likely already doing well at building large structures in space.

 

Though they don’t live in vacuum, your idea reminds me a lot of Larry Niven’s fictional Integral Trees. If you’re a long-time SF reader, you likely know all about them – if your don’t, I recommend you get to know them and the rest of Niven’s wonderful Smoke Ring world (my favorite science fictional world).

 

This feasibility stuff is fun! Let’s see if we can get your story on solid engineering footing.

[Eclogite]

I was also immediately struck by the parallel with Niven's Integral Trees. Which also reminded me of another tree type, possibly in a short story. That manufactured an explosive mix of chemicals which, at maturity shot the tree off the planet so its seed pods could drift through interstellar place until chancing on another planet. Crazy, but wonderfully imaginative.

[CraigD]

Which also reminded me of another tree type, possibly in a short story. That manufactured an explosive mix of chemicals which, at maturity shot the tree off the planet so its seed pods could drift through interstellar place until chancing on another planet. Crazy, but wonderfully imaginative.

;) OK, time for showing off how geekishly voraciously I read SF, by recognizing the story you're describing:

 

I bet you’re thinking of “the Green Disk”, “home to the Symbionts, the only known self-reproducing non-intelligent machine-organic hybridization”, from Asteroid Monte by Craig DeLancy, a short story published in Analog SFF, Sep 2011, and like most that make it into a high-quality pro publications like Analog or Asimov, an excellent story.

 

Plants that shoot seed/spore pods into space to find fertile soil on new worlds is a common theme in panspermia scenarios – I’ve seen them nicely animated in at least one TV documentary on the subject. I’ve not encountered it in many SF stories, though one such story is one of my own many unfinished, unpublished ones. :)

[tercentennial]

I'm sorry it took me a while to make my way back here. I appreciate the input I've gotten so far. My understanding of engineering is a bit shaky, if anyone noted from my username my background is primarily medical so any thought or critiques are greatly welcomed. Before I get to a response, I figured I'd dump a little more info about my project, in particular the reason I'm looking at some off the wall bootstrapped alliterative technology.

The time I'm looking at for my setting is the 2-3 years or more leading up to 2074. Most of the economy slash infrastructure in my setting relies more on open source technology and crowd sourcing than, franchises or huge conglomerates. There is a greater blue collar work force, and in general that workforce requires a greater technical competences than in the past. The U.S. government has both grown but also in a way become more co-op than before after the fallout from the financial crisis settled. One result of this is that a lot of the plans ideas and labor for the american entry into this space race is open sourced.

My character outlines are pretty much done as are a lot of plot elements, some portions of what I wrote in the preceding paragraph are more than likely to be change or are just out lines.

I hope this will shine a light on what sort of ideas I'm after though, and as always if anyone has a harebrained approach or alternative to space exploration I'd very much like to hear it.

My first Post was a but rushed, for instance I neglected to mention that the O2 was only a part of the fuel used for the stair craft. My original idea if I could b=have explained it a bit better the first time was that lasers where placed at each of the three or more Steps starting at the ground and working up, the craft also carried a solid fuel for which O2 gathered at each of the steps was the oxidizer. Each airborne step, I picture them as somewhat doughnut shaped airships, would in preparation for launch of the stair ship collect pure O2 from the atmosphere and release it as the ship passed by. The Ship it'self would suck the air in quickly as it passed and use it with its solid fuel to maintain momentum as it got farther away from each Step before picking up the beam again at the next one. It would dock at a maned LEO station for conversion to a solar sail craft to be pushed by a fleet of converted SBSP satellites in orbit and farther out.

As to the trees, yes I will admit The Integral Trees is a favorite story of mine and references to it did cross my mind. However the trees I was picturing are a bit different. Heavily genetically modified they are grown inside of a space station until their bark matures enough to survive exposure to vacuum. They are developed as a way of stretching resources. They survive as a part of the wast processing for the station, converting CO2 into a bit of O2 and gathering nutrients from waste products extending any resources delivered to the station. The assumption I'm working on is that genetics are more reliable than say nano tech in the future and subsequently using a living material allows for smaller deliveries and supplies delivered to be multi-use.

One other assumption I'm working on is that the future US has established LEO and Lagrange stations but very little out side the earth moon system besides whats being built during the time line of the story. I cant wait for any more feedback anyone might have.

[CraigD]

http://scienceforums.com/topic/24369-two-possible-alternatives-to-se-and-building-large-ships-in-orbit/

 

I'm sorry it took me a while to make my way back here. I appreciate the input I've gotten so far. My understanding of engineering is a bit shaky, if anyone noted from my username my background is primarily medical so any thought or critiques are greatly welcomed.

Good to see you back, Andrew! Though I’m a medical computer programmer, being non-military, I didn’t recognizing the meaning of the “68w” in your name ‘til you mentioned it. It’s good to learn new minutia.

 

You seem to have similar reading tastes to mine, so I’ll throw out a few fiction and non-fiction references on the subject of short-range space colonization I’ve liked over the years:

• Classic space elevators – if you’re setting your story 50+ years in the future, I think you’ve got to seriously consider that one or more of these might be built by then
  
  • Arthur C Clarke’s The Fountains of Paradise – this is the classic space elevator story, with a first contact story and a Sri Lankan historic fiction thrown in, and just a well-written novel (not too many poorly-written ones win Hugos and Nebulas, as this one did, in 1979). Despite the title, which might make a present-day reader expect a space fountain, this is a classic, diamond-cable space elevator with center of mass at geostationary orbit , traversed by self-powered electric cars
    
  • 
    Yukito Kishiro’s Battle Angel Alita: Last Order – this is a manga, appreciated mostly for its high-quality detailed drawing, action, adventure, and like much manga, vaguely pornographic elements, but also a wild, sometimes hard, sometimes soft SF setting, which includes a pair of space elevators and an orbital ring. The orbital ring, a somewhat more obscure concept than geostationary orbit space elevators, is appealing, because it can have its top at a much lower altitude (200 to 2,000 km, vs geostationary 35,786 km)
    

  [*]Getting to orbit with balloons/blimps/etc – Intuitively a pretty weird idea, there’s actually one serious aerospace company working on this ...

  • US company JP Aerospace’s “Airship to Orbit” system – this system consists of 3 distinct vehicles, one that travels from ground to a “Dark Sky Station” at 43 km (140,000 ft) altitude, the DSS, and another that travels from 43 km to orbit (160+ km). We discussed it here at hypography a early this year, in Airships to Space?
    Major differences between JP Aerospace’s stuff and what you’re describing, Andrew, are that the DSS is manned, not unmanned, and all of the vehicles are essentially blimps.
    

  [*]Single Stage to Orbit – If it were cheap and easy to reach orbit, we’d likely not be talking about space elevators and alternative rockets. The problem with SSTO is primarily one of energy density and specific impulse – present day rockets barely have enough energy and reaction mass to reach orbit discarding most of their machinery in multiple stages. A couple of proposed solutions:

  • Skylon – Despite its engines looking like turbo or ram jets, this proposed spaceplane’s are actually complicated multi-mode rocket engines, called SABRE for “Synergistic Air-Breathing Rocket Engine”, that use some of the air encountered at up to about 28 km altitude as reaction mass, liquefy and store oxygen from some of it, then operate as a liquid hydrogen/oxygen rocket. The UK company behind this system, Reaction Engines Limited, appears to have good funding, and has had some success in the past year demonstrating of a prototype key engine systems, the heat exchanger that allows liquid hydrogen to cool hot, compressed incoming air enough to liquefy oxygen.
    No radically new technology in SABRE or Skylon, just clever, innovative combinations of and improvements in existing technologies.
    
  • Thermonuclear rockets. The 1950 movie Destination Moon, which Robert A Heinlein had a lot to do with, was one of these. The US built and ground tested several of them from 1955 to 1973, but never flew one. Enthusiasts have promoted the technology on and off since then – for example now URL-defunct NuclearSpace.com’s ”Liberty Ship”, which proposed improving the old Heinlein-era designs by keeping the nasty radioactive stuff out of the air by containing it in high-temperature glass, AKA a “nuclear lightbulb”. Discussed here a couple of years ago in Nuclear light bulb space craft “Liberty ship”
    
  • Antimatter rockets. There is no higher energy density fuel than antimatter. The fact that we’ve only been able to manufacture and store minute quantities of it (as anti-hydrogen), at costs in the US$100,000,000s, doesn’t change that.
    In his 1995 alternating chapter nonfiction/fiction book Indistinguishable from Magic, Robert Forward wrote some of the best speculation on the use of antimatter as a rocket fuel (in the simplest designs, to create water steam exhaust using nothing more complicated than porous tungsten), and how it might be manufactured cheaply enough to replace present-day fuels.
    

 

Most of the economy slash infrastructure in my setting relies more on open source technology and crowd sourcing than, franchises or huge conglomerates.

Whenever I think of near future business and economics, I think of a couple of future histories beyond the “traditional” ones (eg: Heinlein’s “only veterans can hold public office”, from his 1959 novel Starship Troopers)

 

Charles Stross’s 2005 Accelerando, a standout on the idea of post-scarcity, AKA abundance, economics, and a fun, wild ride of a novel. The basic idea behind post-scarcity is that, in the same way that technology has made once expensive commodities such as paper and computer storage practically free, it will eventually make all commodities practically free. Only novelty – information new, to the buyer – will have economic value.

 

Much as I enjoy it in fiction, I think abundance economics is naive theory, because it assigns to little importance to the ability of people to preserve existing governmental and legal systems that benefit them. In Stross’s novel, efforts by “the establishment” to stop the titled “accelerando” of business practices (which are not really based on an open source model, where intellectual properties are entirely eliminated in favor of providing services to support informations for which only authors have the expertise, but on, essentially, very low-friction, moneyless capitalism with strong contract law and extensive informal quid-pro-quo) are depicted as misguided and ineffectual – for example, early protagonist Manfred’s chief nemesis US IRS agent Pamela is also his love interest, and mother to their daughter Amber, the main protagonist of the remainder of the novel. Though Accelerando hints at some reasons why such may not be true indefinitely, I think it unrealistically discredits the history-proven maxim that “political (and business) power grows out of the barrel of a gun”.

 

Cory Doctorow’s “whuffie” based economy, from his 2003 novel Down and Out in the Magic Kingdom, is another well-knows and thought out possible post-scarcity economy.

 

In my enthusiasm for the subjects, I’ve rambled in this post. Getting back to specifics, I recommend against including your “space staircase” scheme in a hard SF story. As I showed in my previous post, there’s little energy gain in launching the same rocket ship, beam-powered or conventional, from the ground and one or a series of higher-altitude a lighter-than air stations. Though at first glance, this scheme seems similar to JP Aerospace’s Dark Sky Stations (links above), their design calls for changing vehicles at the station, from one designed for the trip from ground to 43 km to one designed for the trip from 43 km to orbit. This isn’t done to reduce the final stage’s energy requirements, but to allow different vehicles optimized for the different flight domains. The ground-to-station vehicle is propeller driven (the propellers are needed only for the highest part of its flight, where it’s no longer lighter than air – below that, it operates as an unpowered balloon). The station-to-orbit vehicle, which is much larger, is ion-thruster propelled.

 

I wouldn’t rule out a center-of-gravity at GEO space elevator – let’s call it “Clarkeian” – as progress in material technology suggest building cable will be feasible in the near future. Because of its mechanical simplicity and lower total system mass, despite having higher strength requirements, I believe a Clarkeian space elevator is more feasible than an orbital ring (let’s call it “Brichian”, after Paul Birch). Space elevators of all kinds carry some political/business repercussions, though, as they’re presumably very expensive to build, so will be controlled by whatever nation or company builds them.

 

I’d also give serious thought to antimatter-powered SSTO (and beyond) spacecraft. At first glance, these seem Buck Roger-ish – small or large airplane-like vehicles that can simply fly into space – but if the technical challenge of manufacturing antimatter in quantities of several grams a year at competitively low cost can be met, they’re scientifically plausible, so lend themselves to more anarchistic milieus. The main drawback is that, like any high-energy density fuel, antimatter enables the making not only of excellent spaceship engines, but of appallingly excellent bombs.

[tercentennial]

Well I'll certainly take your recombination into consideration though for plot purposes a space elevator wouldn't be usable. Given everything I think a motley fleet of ssto craft would be the most suitable alternative. I will use your antimatter powered craft, I can see several possible plot devices I could use with that. Just curious but has anyone worked out the feasibility of A black hole starship? I remember reading a blurb on it while browsing wikipidia but not much else. As far as my future economics, parts of it play heavily into the plot and I left it out for reasons of not throwing out to many spoilers. I do hope should I hope should I get it published that I can show you what sort of economic future I've dreamed up and I hope it's not still naive.

[CraigD]

Well I'll certainly take your recombination into consideration though for plot purposes a space elevator wouldn't be usable. Given everything I think a motley fleet of ssto craft would be the most suitable alternative. I will use your antimatter powered craft, I can see several possible plot devices I could use with that.

I’m delighted you like the idea of SSTO antimatter heated exhaust rockets, though I’d say attribution for the idea should go to Robert Forward, who though not the first to suggest the idea, put it into a readable package in his Indistinguishable from Magic.

 

A few Key thing to keep in mind with antimatter power schemes of any kind:

 

There’re effectively no useful concentration of naturally occurring antimatter (unless one SF premises there are, but that’s a whole different story :)), so it must be made, not found.

 

Making antimatter, while an everyday activity (so much so that CERN calls its system for collecting them, which in the 1990s managed to actually put together the first antihydrogen atoms, ”the Antimatter Factory”, is a present, and even with the kind of efficiency improvements Forward and others suggest, very energy inefficient, requiring on the order 1,000,000 units the energy input to produce 1 unit of usable antimatter fuel. So an antimatter factory of the kind needed to supply fuel to spacecraft would need to have huge amounts of energy input, almost certainly requiring it to be in space, ideally as close to the sun as possible. Once you’ve got a good plant cranking it out, however, you can get it to wherever you need it easily, because it can fuel very powerful and energetic rockets. Because an entire SSTO space fleet would need only perhaps a kg/year, there’d be no such thing as “tanker”, as practically any antimatter powered rocket would be able to carry up to all the antimatter the world needed in a single trip.

 

Keeping the antimatter factories free and safe could be a challenge, as anyone controlling them would have a monopoly beyond the wildest dreams of the greediest 1970s OPEC oil baron.

 

On the other hand ... since Forward wrote his stuff, microscopic, self-organizing manufacturing technology (I try to use the term sparingly, because it has so much nonsensical baggage, but I mean nanotechnology) has become much more well-know, credible, and promising, so rather than needing specialized particle colliders, decelerators, coolers and traps as at present, something like clouds of tiny Earth-orbiting “smart pebbles”, with miniature antimatter collecting and storage machinery might be the technology of choice. For plotting purposes, this is much more nicely … punk than big sun-orbiting factories prone to monopolistic control. Cosmic rays, consists primarily of protons, but due to collision in interstellar space, about 0.01% of them are antiprotons. A given m² in the upper atmosphere or in space gets about 1000 protons/sec, so you’d have to cover a vast area to collect enough antiprotons (positrons, AKA anti-electrons, are easy to get from nearly any radioactive substance) to make much antimatter – my preliminary estimate based on those numbers says an area of about a square 1,000,000 km wide given 100% catching efficiency for 1 kg/year, about the area of the circle inscribed by the Moon’s orbit – but at least it doesn’t seem at a glance outside the realm of SF possibility.

 

Just curious but has anyone worked out the feasibility of A black hole starship?

Black hole power is pretty simple, physics-wise – just pick your power requirement P, plug it into the equation for Hawking Radiation power (slightly wrangled),

 

[math]M = \sqrt{\frac{\hbar c^6}{15360 \pi G^2 P}}[/math]

 

And calculate the needed mass M of the black hole.

 

Using P = 10¹³ W, a few times the total generated power of present day humankind, I get a mass of about 10¹⁰ kg, about the mass of the Great Pyramid, with an event horizon given by

 

[math]r_s = \frac{2GM}{c^2}[/math]

 

Which works out to … so ridiculously, less-than-an-atom tiny I’m not even bothering with the arithmetic.

 

The engineering, however, is a staggering. The only serious speculation about it I’ve read suggests, somewhat like Forward’s antimatter factory, giant close-to-the-Sun solar powered lasers focused precisely on nearly the same point in space to create the black hole. Then you must mate it to a spaceship in such a way it provides thrusts, engineering so far beyond our current ability to conceive, I think, that we can barely speculate about it plausibly.

 

A key, troublesome characteristic of Hawking Radiation, and thus BH power, it that the less massive a BH, the greater its power, so you can’t develop the engineering with small prototypes that you gradually scale up. BHs much smaller than the one I play with above have such great power and short lifetimes they’re essentially tremendous bombs (some astronomers think such BHs, left over from the early moments of the big bang, are the sources of very compact, energetic events like gamma ray bursters).

 

... but I rant. Bottom line, I don’t think BH power is plausible/feasible in the near future. Personally, I wouldn’t want anybody working on it anywhere in my solar system – some reasonable catastrophic failure scenarios are mind-bogglingly destructive.

 

As far as my future economics, parts of it play heavily into the plot and I left it out for reasons of not throwing out to many spoilers.

Yes, please avoid spoilers, as I’d love to read the book. :thumbs_up

 

I do hope should I hope should I get it published that I can show you what sort of economic future I've dreamed up and I hope it's not still naive.

Some years ago I reached the opinion that even the brightest and best educated are effectively naive at predicting future economies, and just tried to enjoy future history fiction that I find makes sense and is entertaining, like Stross and Doctorow’s.

 

I’m enthusiastic about the current state of publishing. While Norman Spinrad (who I think is a truly brilliant SF and mainstream writer) writes of a “publishing death spiral”, folk like Mark Coker of going-on-4-year-old SmashWord are way more optimistic (examples here and here), and putting their optimism into action. While Spinrad likely right that it’s a bad time to be a famous SF I think this may be the best time ever to begin being a professional science fiction writer.

[tercentennial]

I've been researching a few proposed antimatter based designs and currently I think a Solid Core SSTO Design relying on positrons annihilating withing their MAD (Micro-scale Assembly Device) MSRM MiSeR-M or Misers (Micro-scale Self-Replicating Machines) collectors, your smart pebbles as a first step to space and earth-moon system workhorse craft. The larger craft design is based on the red shift rocket design but using Positronium and/or Di-Positronium as its fuel source within the particle beam. Plus as a side benefit the particle beam could serve as a backup drive for the ship, allowing it to bleed off some of its acceleration in an emergency or as a maneuvering rocket when very gradual course corrections are needed and fuel is needed to be conserved. Generally though it probably wouldn't shift in to red shift mode until after it spent some time as a solid core design. I'm still considering a few different ideas for main power for the ship when not under red shift acceleration and I will post back ideas I come up with or take any proposals into consideration.

http://www.kschroeder.com/archive/1024584436/index_html.html

http://www.enotes.com/topic/Redshift_rocket

I was thinking that Positron/positronium/di-positronium being much more easily created at least compared to antiprotons and such and the annihilation of positrons generally produce only gamma rays compared to again antiprotons and such that it would make a much better fit for the red shift proposal. Also Positronium which has a known average lifetime would not require a reaction chamber behind the space craft. The question becomes is this a feasible design, also rather than red shifting the gamma rays down to ultraviolet would it be enough to go only to x-ray. I remember hearing about a specially designed material years ago that generated energy when x-rays where passed through it though I cant seem to remember what it was called.

Oh well still a work in progress but I'm starting to feel good about a lot of the design concepts now.

[tercentennial]

Well I've been a way for a while and got a few more ideas I'd like to put out there slash get help with.

Slow light technology used for gamma rays and other high energy radiation as a means of extracting energy from spent uranium in a mostly enclosed environment. Assuming some material that could safely absorb these slowed rays and turn them into heat or other energy, could they be used as a source of lift in a atmospheric craft of some sort with minimal radiation leakage. IE a pulsed RAM/SCRAM jet version of Project Pluto minus the fallout particles littering the environment. Alternately a VTOL craft that uses thermal jets for lift and/or propulsion.

Also I thought better about the red shift rocket idea, while I liked the possibility of a man drive that could be easily jury rigged into a more traditional electric rocket for plot purposes, also a wooden space ship with a "sail" was quite appealing, I realize its just a waste. A more traditional Solid Core slash antimatter powered Orion it is, though perhaps modeled more on the Medusa or AIMStar or a Medusa AIMStar hybrid, I really love the idea of having a sail.

Well I hope to hear back from someone soon.

[sigurdV]

...one of my own many unfinished, unpublished ones. :)

Interesting! Why not publish in here somewhere?

[sigurdV]

...The assumption I'm working on is that genetics are more reliable than say nano tech in the future...

I expect them later on to marry!

Hopefully we will be able to survive naked in empty intergalactic space, feeding and growing by the casimir effect, transforming energy into mass, all this taking place at nano level within genetically modified mitochondria.

Seeding intergalactic space with living matter growing exponentially might be whats needed to generate enough gravity to stop the dark energy from destroying our universe...

Happy new infinity wishes: sigurdV, Saviour of Universes. :lol:

[Eclogite]

;) OK, time for showing off how geekishly voraciously I read SF, by recognizing the story you're describing:

 

I bet you’re thinking of “the Green Disk”, “home to the Symbionts, the only known self-reproducing non-intelligent machine-organic hybridization”, from Asteroid Monte by Craig DeLancy, a short story published in Analog SFF, Sep 2011, and like most that make it into a high-quality pro publications like Analog or Asimov, an excellent story.

Unfortunately it is not that one. I haven't read an SF short story this century and rarely read SF novels anymore. I find very few authors who carry me away with the sense of wonder anymore. (Baxter and Reynolds are two exceptions.) The short story I am recalling (badly) I would have read in the 70's.

[CraigD]

Slow light technology used for gamma rays and other high energy radiation as a means of extracting energy from spent uranium in a mostly enclosed environment. Assuming some material that could safely absorb these slowed rays and turn them into heat or other energy, could they be used as a source of lift in a atmospheric craft of some sort with minimal radiation leakage. IE a pulsed RAM/SCRAM jet version of Project Pluto minus the fallout particles littering the environment. Alternately a VTOL craft that uses thermal jets for lift and/or propulsion.

Nuclear fission thermal rockets and jets are a venerable concept, fairly proven with prototypes in mid 20th century under the aegis of cold war secrecy. Since then, some improvements in design have been made, most notably IMHO the “nuclear lighbulb” design, an energy-efficient design where high-temperature glass prevents the escape of radioactive material into the atmosphere - a big selling point with people who breath air, which is to say, the human race. ;)

 

I like to keep a perspective on propulsion technologies by considering the energy density of their fuels.

Chemical fuels have about [imath]1.2 \times 10^{8} \,\text{J/kg}[/imath],

fissile nuclear fuel [imath]2 \times 10^{13}[/imath],

fusion about [imath]3.4 \times 10^{14}[/imath],

antimatter [imath]1.8 \times 10^{17} [/imath], the greatest energy density a fuel can have.

 

Intuitively, then, we can see that nuclear fission gives about a 10,000 times improvement over chemical fuel, fusion about a 10 times improvement over fission, antimatter about a 100 times improvement over fusion.

 

So fission powered rockets, modernized descendents of the ca. 1970 NERVA like the nuclear lighbulb can, in rough principle, give the performance needed for SSTO, accelerated (vs. efficient transfer orbit) interplanetary travel. The limiting factor on these and any thermal rocket technology is the need to carry reaction mass, which is measured by its specific impulse, which is equivalent to the rocket’s exhaust speed, and determined by the strength of the system, with solid pressure chambers like the NERVA’s being least strong, gas cores with solid nozzles like the nuclear lighbulb’s next, and powered magnetic chambers and nozzles being most strong.

 

The next improvement is to dispense with separate reaction mass, and use the byproducts of the power producing mechanism as reaction mass. A redshift rocket does this, cleverly, by ejecting antimatter and matter with which it annihilates to near lightspeed, so that when they collide, the very high frequency photons released are redshifted into lower frequency (eg: visible light) that can be reflected, providing thrust in the manner of a lightsail (though such a rocket might not need to much resemble a typical lightsail, as the annihilation zone could be very close to a small reflector.

 

Pulling back to a broader engineering view, any system that used fuel is limited by the [imath]1.8 \times 10^{17} \,\text{J/kg}[/imath] maximum energy density of any fuel, so the next dramatic improvement involved not carrying fuel (that is, energy), but getting it externally. I can think of 2 ways to do this: beamed power, and getting power from the vacuum energy.

 

Also I thought better about the red shift rocket idea, while I liked the possibility of a man drive that could be easily jury rigged into a more traditional electric rocket for plot purposes, also a wooden space ship with a "sail" was quite appealing, I realize its just a waste. A more traditional Solid Core slash antimatter powered Orion it is, though perhaps modeled more on the Medusa or AIMStar or a Medusa AIMStar hybrid, I really love the idea of having a sail.

Keeping engineering categories straight, we need to note that AIMStar and similar schemes aren’t true antimatter-powered rockets, but rather nuclear fusion-powered rockets that use antimatter to trigger fusion.

 

Because they’re an example of the non-fuel limited kind of technology I outlined above, I’m enthused by lightsails, too. If pushed by artificial lightbeams, they can have arbitrarily high accelerations. The need to navigate using narrow artificial beams adds lots of interesting navigation calculations, and SF plot opportunities.

 

 

Hopefully we will be able to survive naked in empty intergalactic space, feeding and growing by the casimir effect, transforming energy into mass, all this taking place at nano level within genetically modified mitochondria.

The Casimir effect is, at present, the only experimentally demonstrated means of getting power from the vacuum energy.

 

It’s important, I think, to understand enough about the Casimir effect to realistically imagine how it might be used as a practical (as well as unlimited and free) power source. In essence, two precisely made plates precisely positioned very close together (on the order of 10^-8 m) apart experience a strong force. If the plates move under the influence of this force, they can do physical work, converting vacuum energy. Once the places can move no closer together, no more work/energy can be extracted from them. Restoring them to their original position, however, requires at least as much energy – it’s basically like a steel spring, except that you can get one “stroke” of “free energy” from the system.

 

So, to make a practical engine base on the Casimir effect, the engine must effectively create, extract energy from, and discard a series of devices like the lab apparatuses that first demonstrated the Casimir effect in the late 1950s, but with much greater ratios of closely spaced plate surface area to volume (experimental apparatus are bench size, have an effective plate area on the order of 10^-4 m², and produce a barely measurable force), and with less work than it generates. That’s pretty challenging engineering, on any scale.

[sigurdV]

The Casimir effect is, at present, the only experimentally demonstrated means of getting power from the vacuum energy.

 

It’s important, I think, to understand enough about the Casimir effect to realistically imagine how it might be used as a practical (as well as unlimited and free) power source. In essence, two precisely made plates precisely positioned very close together (on the order of 10^-8 m) apart experience a strong force. If the plates move under the influence of this force, they can do physical work, converting vacuum energy. Once the places can move no closer together, no more work/energy can be extracted from them. Restoring them to their original position, however, requires at least as much energy – it’s basically like a steel spring, except that you can get one “stroke” of “free energy” from the system.

 

So, to make a practical engine base on the Casimir effect, the engine must effectively create, extract energy from, and discard a series of devices like the lab apparatuses that first demonstrated the Casimir effect in the late 1950s, but with much greater ratios of closely spaced plate surface area to volume (experimental apparatus are bench size, have an effective plate area on the order of 10^-4 m², and produce a barely measurable force), and with less work than it generates. That’s pretty challenging engineering, on any scale.

All above very true, and I wouldnt have bothered unless having some reason behind the suggestion:

 

The hidden agenda here is what life should do to survive in a universe being rendered apart by Dark Energy?

Obviously DE can be counteracted by creating enough gravitation all over the universe? The only way I could think of to do so was to turn free energy into mass... (When the plates have done their work once, their mass is still part of total mass! They dont have to be reused to produce energy... all that matters is if they produced more energy than was used in order to create them out of already existing mass.)

 

In addition: Producing lots of mass might produce lots of black holes to juggle around in space so its better done intergalactic.

 

However: The time perspective worries me some. Will the exponential growing rate of life suffice if it has the speed of light to fight against?

 

Also: It was the Spheres imagined by Freeman Dyson that woke me up to the fact that our basic equations cant predict the eventual coming of some large scale events (like : Light suddenly stops coming from a star...) There must be important parts missing in our tool box... May I point out the definition of "life" given by Ilya Prigogin as a possible example of inspiring things overlooked that should be given attention?

 

PS Good luck with the ship and the book Andrew, sorry if ive been intruding :)