Envisioning the world of 2100

Discussion in 'Science and Technology' started by RAMA, Aug 9, 2012.

  1. gturner

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    Keeping the aluminum molten in just an insulated tank is pretty simple because it has a huge thermal mass. Getting it molten is also simple with just resistance coils or even tungsten halogen lights in an insulated oven (which would describe the fuel tank) because it melts at 900 to 1200F. Of course the simplest way to melt aluminum is probably with a solar reflector, after which you'd pump it into the tank.

    I'd try to heat it much higher than the melting point to improve viscosity and impart a little extra energy, since extra thermal energy in the aluminum translates into better performance as a propellant. If you heat it to 900C you add about 1.2 MJ/kg to the 32.2 MJ/kg heat of combustion, probably raising the ISP from about 285 up to 290, which is servicable as a lunar propellant.

    I'm not sure what experiments have been done with molten metal fuels, though. The probably questions to answer are how the injectors fair. If the engine and tank are being heated prior to launch anyway, and you only depend on one big burn to get into orbit, it wouldn't really matter if residual aluminum in the lines or injectors solidified after engine shutdown, because such an engine would only be used to launch other materials to a fuel depot or assembly station.

    Extracting aluminum on the moon is relatively straightforward, since the most common mineral on the moon is anorthite (NaAlSi3O8), which we're looking at switching to because bauxite is getting harder to find. The cost is of processing anorthite is about twice that of bauxite. You're just going to need a lot of electrical power.
     
  2. gturner

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    It's a tradeoff between the mass of radiation shielding and extra food (and pay!) you need to dawdle through the Van Allen belt versus the mass of fuel you save by taking the high ISP, low thrust route. If the trips are going to be frequent, you'd want to have radiation shielding anyway in case of solar storms.

    You could also provide for both, going light and fast on early missions until you can launch crudely processed lunar material for radiation shielding, and then add that to your ships along with the ion drives. The internal core of the ship (the expensive part) thus gets re-used.

    Or you could think further on the problem and use the extra mass of cargo you're delivering (with the high-ISP engines) as the radiation shielding on the outbound flight, and use cheaper lunar fuel and no cargo to make a rapid return trip.
     
  3. Crazy Eddie

    Crazy Eddie Vice Admiral Admiral

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    The Van Allen belts aren't that big of a problem; shielding against them isn't overly hard, and if you're using an ion engine, you can run a course that partially bypasses them anyway.

    I'm thinking the crossing through the Van Allen belts wouldn't take so long that the crew couldn't ride out that part of the trip in a heavily-shielded central node (three or four days through either belt, depending on the flight profile). Heavier shielding would be an upgrade with better technology, but again, we're talking 2020s, 2030s timeframe and that might be available by then.

    OTOH, I've heard Franklin Chiang Diaz suggest the VASIMR's magnets could be used to provide shielding for a craft during CMEs. A similar technique may be applicable in this case (also, using a VASIMR could reduce your transit time from three or four months to three or four weeks).
     
  4. gturner

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    A couple of days transiting the Van Allen belt shouldn't present much of a mass issue, since Gemini showed you could shove two astronauts in a phone booth for a week. About 6 inches of polyethylene would stop most of it (99%) and with California bans on plastic shopping bags, there should be enough of it freed up for deep space applications.

    Almost any proposal for near-term deep space needs to include something like an upsized, shielded Soyuz orbital module with its own life support, power, sleeping arrangements, and bathroom, which due to its mass and sophistication should be reused across many missions. That means it needs one or more docking adapters and perhaps its own minimal RCS system for station keeping between missions. The ideal way to test the living arrangements would be to attach it to the ISS for several months, perhaps as a block I non-shielded to be followed by a block II shielded version that includes layout and equipment improvements based on experience with the block I. Unfortunately there's no current funding available for such a module because everything is allocated to the SLS and Webb.
     
  5. Crazy Eddie

    Crazy Eddie Vice Admiral Admiral

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    ^ That doesn't strike me as the kind of thing that would be difficult for private companies to tinker with, though. Depending on the mass of the shielding, a radiation-hardenned Dragon would suffice for that application (and Dragon is ALOT roomier than a Gemini).
     
  6. RAMA

    RAMA Vice Admiral Admiral

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  7. sojourner

    sojourner Admiral Admiral

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    Hey! spamming links to unrelated articles! good job. Not one of those links relates to Ghostavo's comments on oil production. Unless you somehow got confused by the word "solar" and thought it meant "oil". And hey, you slipped in a Diamandis TED talk that's about on the level with a TV evangelist? seriously?
     
  8. Crazy Eddie

    Crazy Eddie Vice Admiral Admiral

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    It also leaves out the fact that we are not less than forty years from anything resembling practical asteroid mining.

    And even then, mining asteroids is extremely unlikely to provide any benefit whatsoever to the global economy, for the very simple reason that the demand for those resources will be far higher among off-world outposts and communities than it will be back on Earth. You wouldn't spend forty thousand dollars shipping a kilogram of platinum to a consumer on Earth when you could spend four thousand dollars shipping it to a consumer on the moon, especially if that sale also turns into an investment that strengthens future sales.

    Earth is sitting at the bottom of a steep gravity well, which prevents us from cheaply sending materials into space; it's also surrounded by a thick atmosphere, which prevents things in space from cheaply returning. It is the most literal manifestation of the term "trade barrier," and most of the solar system's resources are on the other side of it. The instant humans begin living in space and using those resources, Earth will ALWAYS be at a competitive disadvantage; and off-world products will begin to replace Earth-made ones almost the instant they become available.
     
  9. publiusr

    publiusr Rear Admiral Rear Admiral

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    Again, STS is a history of HLLV scale operations and nasaspaceflight is full of coherant plans being developed for BEO exploration that VentureStar--which would have cost more than STS--would have competed with.


    Well, it is supposed to lift only 40-53 tons or so. Now some solid augmentation might allow for that if Musk will allow it. But even he is looking at the BFR concept again it seems

    Falcon MCT

    http://www.flightglobal.com/news/articles/spacex-aims-big-with-massive-new-rocket-377687/
    http://forum.nasaspaceflight.com/index.php?topic=30103.0
    http://www.nasa.gov/home/hqnews/2010/nov/HQ_10-292_Heavy_Lift.html

    "7m+ Core, Not RP-1, 150T or larger"

    Now with the fuel you are talking about--this can only increase cargo to the Moon using both methods (large LVs and different fuels.) Besides, using HLLVs allows faster transit than using the pieces-parts method--and Nautilus-X was designed by Mark Holderman, who was a proponent of some form of shuttle derived heavy lifters and External tank applications: http://aeromaster.tripod.com/grp.htm Three or so SLS launches should do the trick.

    Something interesting I saw from the web:

    Given the availability of high efficiency tankage and high T/W ratio engines from SpaceX, then reusable boosters make the lunar surface directly available to earth launched hydrogen upper and core stages with no interim staging, stops or refueling necessary. We've already gamed this out completely and have published our results. Given enough boosters, you could even land an SLS stage on the moon by incorporating the upper stages engines (throttleable Rl-10s) into the interstitials of the four SSMEs.

    We can be there just as soon as current upper stage engines are converted to low gee landing engines. These kinds of engines were tested in the sixties (J2-S) and with the Delta Clipper (RL10A-5).


    Similar: http://books.google.com/books?id=KOQDAAAAMBAJ&pg=PA14&lpg=PA14&dq=Shuttle+External+Tank+on+the+Moon&source=bl&ots=IGS0vXulJX&sig=1py_4jT7m1n3IO-zufKOUvFcorc&hl=en&sa=X&ei=jvSCUI2gKIj48gSs2YH4Bg&ved=0CFkQ6AEwCw#v=onepage&q=Shuttle%20External%20Tank%20on%20the%20Moon&f=false

    All hydrolox HLLV's with no payload other than a docking port themselves can become wetstage station modules with no chemical contamination associated with other fuels, so it isn't as if room need be an issue.

    R-7 is over fifty years old and going fine--and will be developed. The "narrow" tank was probably a result of the meddlers from DIRECT who wanted to kill off the larger Ares V for current ET tooling, which does allow things to get started off easier. BFR will be a bit slimmer if made, but Musk is already working with Dynetics on Stratolaunch--and they are the ones looking at an F-1 comeback for LFBs. They actually might play a part in MCT as well...

    Yep, I've seen molten aluminum carried by trucks over the freeway
    http://www.youtube.com/watch?v=Nhvm_VOOWC0

    Speaking about Gemini, you might find these links interesting
    http://www.wired.com/wiredscience/2012/10/modular-space-station-evolving-from-gemini-1962/
    Dyna-Soar's cousin http://www.wired.com/wiredscience/2012/10/dyna-soars-martian-cousin-bonos-mars-glider-1960/
     
    Last edited: Oct 20, 2012
  10. Crazy Eddie

    Crazy Eddie Vice Admiral Admiral

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    So was Saturn V. How'd that work out for NASA?

    The internet IN GENERAL is full of coherent plans for space exploration, but I wouldn't want to spend a billion dollars putting a piece of Doctor Who fanfiction into orbit.

    SLS is not the Soyuz, and neither was the shuttle. Both are projected to operate at five to ten times the cost at perhaps one third the flight rate; both would be damned lucky to have the Soyuz's success rate.

    But that just raises another interesting point, doesn't it? Why is it that HLVs like Saturn-V, Energia and STS have consistently under-performed in terms of cost to lift ratio and reliability compared to smaller launchers like Saturn-IB and Soyuz? We consider the shuttle program to be impressive -- 140 missions in over twenty years -- but that's small potatoes compared to the R-7 family, with a resume that includes over 1700 launches since they went operational; Soyuz alone accounts for over half of those.

    Falcon 9 has twice the capacity of the Soyuz family, and it's only just entered service. Now imagine what the Falcon family is going to look like with 1700 launches under its belt. Right around the time SLS begins to achieve its maximum carrying capacity, the Falcon Heavy will have already surpassed its Block 1 configuration for about a tenth of the cost.
     
  11. sojourner

    sojourner Admiral Admiral

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    You know, I'll say it right now. If SpaceX decides to build an HLV, I would support it. You know why? Because they will only do it if they can close a business case. It will put SLS out to pasture.
     
  12. publiusr

    publiusr Rear Admiral Rear Admiral

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    They say they will have more in one to three years. This looks to compete with Block II

    Now 1,700 launches, newtype? R-7 was able to do that because it was funded by a nation. I hope Space X is around in 50 years. Remember too--R-7 was considered too large at first too--a product of big gov't too. So while Ayn Rands fictional heros were making skyscrapers, Korolov's cross rose much higher.
     
  13. sojourner

    sojourner Admiral Admiral

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    Because it was affordable to that nation. How many N-1's did they launch?
    For about 10 minutes.
     
  14. gturner

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    Korolev didn't succeed because of the state, he largely succeeded despite it. He had to take an extremely hands on approach, from supervising the designs and the running of the machine shop (basically being their Elon Musk, not their James Webb), to firing any underling who crossed him or screwed up, to walking up to machinists and offering them cash to do things his way. It barely worked, and once he was gone they really couldn't take things much further because government agencies are notoriously non-cooperative.
     
  15. Crazy Eddie

    Crazy Eddie Vice Admiral Admiral

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    Correction: the R-7 was funded by a military. Which means that unlike the Saturn-V and the shuttle, it had a continuing justification to exist irrespective of the nation's political will. Military spending is ALWAYS politically acceptable; peaceful space exploration, not so much.

    Remind me again: what are the potential military applications being considered for the SLS?

    Too large for a practical ICBM, yes. But Korolev didn't built it to be an ICBM, despite the fact that that's what the Soviet military had ordered him to develop. He managed to piggyback his exploration program onto the back of what was essentially a nuclear weapons delivery system, and he was damn lucky to get away with it.

    Consider the question I asked you above. The EELVs all have a much higher flight rate than the shuttle or the SLS can ever aspire to. They get most of their business by handling government contracts, including spy satellites and mysterious automated spaceplanes. Even if we never ever put another American into space, ULA will still be able to stay in business using those defense contracts.

    SpaceX has wisely made a move to make the Falcon 9 available for military payloads as well, especially with their little trick of implying (falsely, I sometimes think) that the Falcon Heavy would be launching primarily out of Vandenburg. Right now they're depending on their service contract to the space station, but if they succeed with the Falcon Heavy gambit, SpaceX too will have a "sure thing" fallback if space exploration bites the political dust and will continue in business through its military contracts.

    I repeat that there are no military payloads being considered for the SLS at the current time. The Air Force and the NRO are happy with the Delta-IV Heavy and the Atlas-V, and they're likely to be even happier with the Falcon Heavy when it becomes operational. SLS is too high profile, too expensive, and when it goes online, too restrictive in its schedule in addition to being untried and untested. That means that SLS is already on shaky political ground, and depends entirely on how fashionable space exploration is in the minds of a collection of fickle voters; its chances of being cancelled would probably double if Star Trek Into Darkness starts getting bad reviews.
     
  16. publiusr

    publiusr Rear Admiral Rear Admiral

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    That is a point I have to concede, only because of how The Air Farce robbed ICBMs from the ABMA. It wasn't just the USSR's military, but their Army. Until recently, artillerymen manned the R-7 pads because a missile is properly artillery.

    Here, Our triad was made of an ICBM force with tiny warheads atop tiny solids. Titans Deltas and Atlas rockets only used for comsats and milsats. If you wanted more than this--you had to compete with fighter jocks for funding. Remember, Nikita wanted R-7 and missiles in that it provided him an excuse to not have to have a blue water navy like ours, or to match us bomber for bomber. Stalin before him wanted an ICBM pronto.

    Here is where the chief designers cooked the books. They told their superiors not to wait until warheads had been shrunken--as we did. Their idea was to make the rocket bigger. Their military knew this and howled, but Stalin wanted his ICBM now--so the result was a space booster sold as an ICBM--rather than vice versa.

    In other words, space advocates actually got what they wanted.

    Over here our two greatest technocrats were not Korolev and Glushko, but Curtis LeMay and Adm. Rickover.

    Von Braun had more money in absolute sense, but less real power in our military--so we had to have a strong NASA to bully up and be an institution all its own. Koptev on the other hand, had no real power angainst Semenov's Energia Crp--and Golden had to give him a bigger voice. Thus even in Russian now, the civilian space force has to have national support. Tough these days with Medvedev going off on them after Phobos Grunt. Not helping. As for me--we should have kept the Army model that worked well for the Soviets with ABMA and General Medaris--but he had no power to stand against Bernie Schriever.

    Atlas V has a good flight rate. Delta IV is a worse pad sitter than shuttle and that was after Columbia. Right now, LockMart is working with ATK on Athena, and Antares is facing the ULA gang who want to prop up EELVs despite their rising costs. Here is what I see, EELVs will be kept around, but so will Falcon 9. SLS will be propped up--but so will (hopefully) MCT to replace Block II. Antares will die, and maybe Delta IV. The downselect will be to Falcon, Atlas and SLS. That is how it looks now because SLS is farther along than MCT

    Now all that is likely to change as such time as it is flying. Remember that space advocates in the Pentagon are on the outside looking in. With NASA picking up the tab on a larger LV, older items such as larger space-based radar and boost phase BMDO projects--depending on who is in the White House of course--may get a second look, especially with Griffin advising Romney and Obama (officially) committed to SLS. Coyote Smith wanted Space Based Solar power, and there are things being looked at that would have no chance from the bottom up with the USAF sitting on things.

    http://www.globalsecurity.org/space/systems/sbr.htm
    www.nasaspaceflight.com/2012/02/sls-dod-market-secondary-payloads-potential/
    http://www.nasaspaceflight.com/2010/07/sd-hlv-early-sps-demonstration-risk-assessment/

    Some arguements are being made pro-and-con..big pdf
    http://timemilitary.files.wordpress.com/2012/09/nrc-bmd-report-2012-09.pdf

    See Major Finding 8a

    Now remember there is "no current market" for MCT either. Musk is hoping to start one. There are no payloads because there is no rocket. There is no rocket because there are no payloads. Chicken, meet egg. SLS and MCT are in R-7's shoes. The Russians could have waited until smaller solids and smaller warheads came along (Topol) but space advocates in being higher up the food chain made the rocket first, then the payloads followed.

    Personally, I want large space based military assets for boost phase ICBM intercept. Right now, we have to have ships at sea with solids in a tail chase against liquid fueled ballistic missiles that can outpace them unless they are very close where the solids hard acceleration have a chance of catching them. other than that, ground based missile defense rely on drones shooting up at a bunch of targets already coming down.

    Space Based assets reverse that. Now such advocacy won't be easy in sequestration--but this allows big cuts to deadwood to be made, with outsiders perhaps using the chaos to their advantage. Khrushchev saw that space-arms was actually the cheaper way to go. I could argue that space based assets are cheaper than keeping this Cold War WWII era logistical nightmare Forget SPSS for power generation ofor civilian use--If I can have a handful of demonstrators keeping an electric drone cap up--then I can argue against carrier groups and endless airplane acquisitions. In other words, the logistics of bodies, bases, beans and bullets cost more than Falcon/SLS-launched rods-from-god.

    This is why space advocates rank below the janitor in the Pentagon--they could make a lot of things obsolete.
     
    Last edited: Oct 23, 2012
  17. Crazy Eddie

    Crazy Eddie Vice Admiral Admiral

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    Eventually, yes. Solid boosters replaced the liquid ones only when the U.S. stopped using fixed missile silos to house the Titans; they switched, instead, to mobile launch platforms that could be moved just about anywhere, thus robbing the Soviets of any hope that they could cripple America's retaliatory missile arsenal by saturating known launched sites with bunker busters and the like.

    The space shuttle managed to avoid cancellation by courting military objectives, resulting in its overly huge delta wing and overly huge payload bay, neither of which were ever used to their full capacity; it did briefly provide a useful vehicle for the deployment and testing of some military payloads until the Challenger accident brought that to an end; it was only then that the need for EELVs became apparent, at around the same time the Air Force started transitioning to solid propellants in ICBMs.

    We did WHAT now?

    No, we didn't wait for the warheads to get smaller, we just accepted a missile with a shorter range until a larger version could be developed and mass produced. You may recall that that larger version was a missile called the SM-65 Atlas -- the forerunner of today's Atlas-V EELV.

    Strictly speaking, since the Russians have stopped using the R-7s as ICBMs, that pretty much makes the Soyuz family the Russian equivalent of America's EELVs. In which case, it must be said that the Atlas has ALSO been in continuous service for over fifty years and has developed considerably over that time.

    Again, that's only half right. Ultimately, Von Braun's development of the Redstone missile -- and the now legendary Redstone Arsenal -- served the same purpose as Korolev's R-7 project: piggybacking an exploration program onto a crash course missile development program. Though their approach was slightly different (primarily due to the differing natures of the governments they worked for) the technique is ultimately the same: Come for the weaponry, stay for the spaceflight.

    You may also recall that Von Braun did the exact same thing when he worked for Hitler. His designs for what eventually became the Saturn-V dated back to the original V-2 rocket program, and Von Braun was dabbling in concepts for manned spaceflight even then.

    I don't see SLS surviving the downselect process, or really, even being part of it in any meaningful way. It's a political football with no actual utility attached, so it's in an entirely different ballgame.

    What will probably happen is that Orbital Sciences will stop dicking around with the Antares and commission either Falcon 9s or Atlas-Vs -- or both -- for their CRS missions (why you insist on blaming the trouble with Antares on ULA is beyond me). Falcon Heavy will probably squeeze out the Delta-IV, which I think ultimately benefits ULA since they can focus on man-rating the Atlas-V. That benefits them because everyone who has ever looked at the SLS immediately realizes that it's much too large to be a practical launcher for Orion alone, and thus Orion is incapable of performing its secondary mission as a possible transport to and from the space station or rescue vehicle if the station has trouble. That, ultimately, would give NASA two or more options for crew transport: Falcon 9/Dragon, Atlas/MPCV, and possibly Atlas/Dreamchaser.

    Which means that while they're throwing money at their congressional mandate to build SLS, private companies can provide their short-range launch capability for Low Earth Orbit at a relatively low cost to NASA (like they already are in terms of cargo transport to the space station). SLS might be viable if NASA or the Air Force can think of something really interesting to use it for; if not, Falcon Heavy will steal its niche and further development will be stalled and/or cancelled beyond the Bloc I configuration.

    You're delusional if you really think that. Even the space shuttle never flew the military missions it was explicitly designed for; what makes you think the Air Force is going to pull a 70 ton payload out of their asses just because an HLV happens to exist somewhere?

    Which is exactly why Musk is likely to succeed where NASA is not. SpaceX has a REASON to develop the the Falcon Heavy and they have high hopes for the development of a self-recovering rocket stage. NASA has no reason to build the SLS; they're building it only because they were ORDERED to, and the only reason they were ordered to was because some congressman was worried about the high tech jobs at KSC.

    No they could not, because the Americans had already begun to position the Redstone missile within striking distance of the Soviet Union. Recall from the Cuban Missile Crisis that the REMOVAL of those missiles from their positions in Western Europe was one of the concessions Kennedy made to have the Soviets pull their launchers out of Cuba; Kennedy was able to do this only because the U.S. was already close to developing a feasible ICBM anyway, and the Redstone arsenal was effectively obsolete.

    In addition to being a massive treaty violation, that would also be of extremely limited utility. Not just because we're not currently in conflict with anyone who HAS ICBM capability, but because of the sheer number of platforms you would need to deploy in order to make such a thing even slightly feasible. More importantly, the low orbits and large size of those platforms would make them relatively easy targets for ASATs, and their destruction would flood low orbit with such massive clouds of debris as to make space exploration a thousand times more hazardous.

    That's not how ABMs work. You don't know what you're talking about.

    No you could not. The Air Force already studied that possibility in absurd detail, first with the MOL program and later during the Star Wars initiative. The technology to make those kinds of platforms feasible is still in its infancy and maturing very VERY slowly, and this at a time when the types of adversaries that would make such a system useful have either vanished or were never in conflict with us in the first place.
     
  18. gturner

    gturner Admiral

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    Well Newtype Alpha, I'll go ahead and argue that an SLS supported moonbase as an ABM and ICBM platfom is critical, just because you're having so much fun shooting fish in a barrel.

    Side note: The military at one point argued for a moonbase for nuclear ballistic missiles, until they realized that such missiles would only strike two or three days after the war ended and couldn't possibly be recalled, so conning them into a premature launch would itself be a a goal, making them the most expensive and useless weapons in the history of warfare.
     
  19. Crazy Eddie

    Crazy Eddie Vice Admiral Admiral

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    :lol:

    Interestingly, the Pentagon did a study a few years ago examining potential strategies in the event of a war with a rogue lunar colony, including the technical, legal and political implications of nuclear and conventional strikes on those colonies and possible retaliatory measures.

    The DoD sure loves their wargame scenarios.
     
  20. gturner

    gturner Admiral

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    One of the commenters at SciFi's BSG forum was an F-16 pilot who'd just returned from Iraq and whose rotation had him training new pilots. I talked up the idea of using a zombie attack as a planning exercise and he used it in class. Given the close proximity of civilians and zombies, strafing runs with the 20mm cannon was crucial.

    I recently read an interesting article on how the zombie genre was born from terrifying rabies outbreaks that once afflicted major cities like Paris, where you could be walking down an alley, get attacked by a rabid animal, and get turned into a mindless, vicious monster. It made sense.
     

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