tag:blogger.com,1999:blog-7494544263897150929.post8322458116562542834..comments2024-03-19T00:19:09.117-07:00Comments on Rocketpunk Manifesto: Home Away From HomeRickhttp://www.blogger.com/profile/16932015378213238346noreply@blogger.comBlogger233125tag:blogger.com,1999:blog-7494544263897150929.post-28380104632164259062021-07-05T16:25:54.352-07:002021-07-05T16:25:54.352-07:00" (If everyone in space is under attack all t..." (If everyone in space is under attack all the time, there won't be much space travel.)" = Rick<br /><br />Everyone in space is under attack all the time ...by space. But in this case, the most relevant threat is random debris. Every space station with traffic will probably have a significant amount of bits and pieces in co-orbit. I assume a working space habitat (especially of the sort posited in your post) will be visited more often than the ISS currently is, in orbits that have less drag than LEO, giving the debris a longer "shelf life". So any space station under those conditions will need some defense against impacts, a Whipple shield at minimum and a laser broom if tech will allow it.<br /><br /><br />"If you're planning to colonize the destination, then the settlers will need to raise their own construction crews." = Milo<br /><br />For early space habitats in the PMF, moving either the hab itself or easily assembled modules from the point of manufacture is the only practical method for any large space habitat. Most likely all plausible early habs will be spacecraft themselves or pushed into place by "space tugs".<br /><br />"Also, will this space station support weapons at all? The facility is mostly populated by civilians, and installing weapons is only asking for trouble." = Fernando<br /><br />Depends on the local crime rate and how much law enforcement is locally available. But everything useful is weaponizable.<br /><br />"2. People are rational, and will recognize the unprovoked destruction of a station and it's occupants as a war crime." = Byron<br /><br />We are not Vulcans!<br /><br />"I've been assuming that a large portion of our discussions on this blog rely on a solar system populated enough to support things like basic off-world industry, at least limited interplanetary travel outside the most efficient launch windows, and at least some people living off-Earth full-time." = Raymond<br /><br /><br />Basic industry will include at least the mining and distilling of volatiles and collection of regolith, which might plausibly be done at existing tech level (though with much engineering and field testing required). Adapting any more complex processing or manufacturing than that needs innovation. How much infrastructure gets built in the PMF is not readily foreseeable.<br /><br />For dramatic purposes of course, a populated Solar System implies an industrialized Solar System. So building habitats can be done at least partially using space construction rather than just assembling modules.Saint Michaelnoreply@blogger.comtag:blogger.com,1999:blog-7494544263897150929.post-85072180292495589822012-02-11T20:20:25.041-08:002012-02-11T20:20:25.041-08:00Cat-keeping in space was so much easier in old Hei...Cat-keeping in space was so much easier in old Heinlein stories!<br /><br />I didn't even know there was a cat in zero gee video. Interesting, not to mention bizarre. That puss was really confused!<br /><br />Assuming that cats do adjust, I wonder if other cues would serve to identify rock outcroppings for them to watch the cabin from.Rickhttps://www.blogger.com/profile/16932015378213238346noreply@blogger.comtag:blogger.com,1999:blog-7494544263897150929.post-16708117919144135252012-02-10T09:46:03.600-08:002012-02-10T09:46:03.600-08:00FWIW, I think common household pets - at least the...FWIW, I think common household pets - at least the types that are common today - might not work for a station of 10,000 or so. If the environment permits pets at about the same ratio as on Earth (which is unlikely, given the supplies you'd need to sustain them), that'd mean <a href="http://www.avma.org/reference/marketstats/ownership.asp" rel="nofollow">somewhere between 6000 and 7000 cats</a>. (A similar number of dogs, as well, but I'm a cat person, so I'm not as familiar with what's required to support dogs.)<br /><br />That sounds like a lot, but I don't think it is, not in genetic terms. If they were all, say, Domestic Shorthairs or Domestic Longhairs, you'd probably be fine. Any purebred cats would likely be the last of their line on the station: there would be so few others of their breed that they'd have to mate with other breeds; several breeds have recessive genes responsible for some nasty traits. In a huge population, it's trivial to breed them to another line in that breed; on a space station, it's practically impossible.<br /><br />Of course that's assuming that the cats are not spayed/neutered before being brought aboard, and also that growth is monitored closely to keep the population reasonable. (That itself is not a trivial task.) If they are fixed, then the only source for pets is the PetCo Shuttle, and it seems unlikely that cargo space on plausible mid-future shuttles would be used to transport pets. (I guess it would be life-support space rather than cargo space, but space nonetheless ... and you would have to provide supplies for them like you would for human travelers. No big deal for a seven-day trip from surface to orbit, more than a small consideration for a month-long trip.)<br /><br />Speaking of supplies, it's true that you'd have to have appropriate food (and water) supplies for the cats ... if they're eating, say, mice, then you have to have supplies and such for the mice as well, all the way down the line. Even if you try to make your own cat food, it's still going to be meat-based, and it seems like a lot would be required to support a few thousand cats. <br /><br />Medical care would be a mixed bag: from what I understand, vets study some of the same subjects that doctors do, branching off once they get the basics down. (It's mostly the same pieces, just put together differently.) It's possible/likely that you could have one or more doctors with vet knowledge, or failing that, vets with enough doctor knowledge to serve as backups (so they're not totally focused on pets). <br /><br />Medicine would be the same as for people (sometimes literally, just in smaller doses): some medicine would come from the same sources as medicine for humans (made on board, if that's the goal, or arriving on the five-year shuttle or whatever), and some you probably just wouldn't stock. There might even be value in not treating certain types of genetic diseases, because you might be able to breed those out of your Spacefaring Shorthairs. <br /><br />I feel like there are other parts of the pet-support business that I'm missing (physical maintenance to keep claws and fur from damaging the station) ... but on the other hand, there's a pretty significant psychological boost to having pets around, and given that this is mid-future, psychology itself could be enough of a reason to try to make this happen.<br /><br />As for zero-gravity environments, well, cats probably wouldn't react well at first (see the cat-in-zero-gravity video), but then if you put the appropriate substance on the "ceiling" they wouldn't have any trouble getting "up" there, would they? (The worst part for cats would no doubt be the realization that without an actual "up", there would be no high places from which they could survey their surroundings.)zlionsfanhttps://www.blogger.com/profile/02966540737106797756noreply@blogger.comtag:blogger.com,1999:blog-7494544263897150929.post-66565776664108194622010-11-21T20:38:46.607-08:002010-11-21T20:38:46.607-08:00Lifting the quantities of water needed from Earth ...Lifting the quantities of water needed from Earth would require hundreds of Saturn V class launches for each assembled spaceship, a practical and economic impossibility.<br /><br />Getting that amount of water can only be done by extracting it from a NEO. Since many NEO's can be reached with less delta V than needed to get to the Moon and back, current technology should be able to do the job. NERVA type NTR's or Solar Moth's would be better in terms of getting more mass to the target (and VASMIR might be better still), but there seems to be no conceptual reason that we could not do this, if we were willing to devote the resources to the project.Thucydideshttps://www.blogger.com/profile/09828932214842106266noreply@blogger.comtag:blogger.com,1999:blog-7494544263897150929.post-85956411646468361472010-11-19T12:34:10.303-08:002010-11-19T12:34:10.303-08:00You guys missed my point. Water is so valuable fo...You guys missed my point. Water is so valuable for life-support purposes and radshielding that it's worth hauling up out of the grav-well, even at ~$100m/lb. If you can find it from NEOs, that's great, less to haul up from the surface, but I expect to see megatons of water going up with a serious space presence.Scotthttps://www.blogger.com/profile/08876828579688122237noreply@blogger.comtag:blogger.com,1999:blog-7494544263897150929.post-1606762675237186472010-11-18T20:35:57.378-08:002010-11-18T20:35:57.378-08:00Since we seem to have decided that the only differ...Since we seem to have decided that the only difference between a ship and a station is the lack of a bus; a movable base for exploration of NEO's could be useful; the base/ship could be a (relatively)cheap hab module with an attached lander, solar panels, support module, and a cheap drive. Think of it as a wenibago fitted for space exploration; trade out the crew every few months and move it to a new location at the end of each mission. The whole thing could be launched in small sections, perhaps even inflatable with water, and assimbled in orbit. The ISS would gain another mission; assimbling, servicing, and coordianting these wandering base camps...<br /><br />FerrellAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-7494544263897150929.post-91807672121330339712010-11-18T16:02:15.352-08:002010-11-18T16:02:15.352-08:00Tony:
Surface volatiles, I should say. There are ...Tony:<br /><br /><i>Surface</i> volatiles, I should say. There are still <a href="http://en.wikipedia.org/wiki/Extinct_comets" rel="nofollow">dormant comets</a> like <a href="http://en.wikipedia.org/wiki/14827_Hypnos" rel="nofollow">14827 Hypnos</a>, which are possibly comets whose nuclei have been covered in a few cm of other materials, and thus don't outgas at present (but still may be mostly ice).<br /><br />I say we wait until we have a few more core samples from various NEOs before dismissing it entirely.Raymondhttps://www.blogger.com/profile/18103471451043461302noreply@blogger.comtag:blogger.com,1999:blog-7494544263897150929.post-35692670734006917582010-11-18T05:05:43.777-08:002010-11-18T05:05:43.777-08:00Raymond:
"...the asteroid categories include...Raymond:<br /><br /><i>"...the asteroid categories include both rocks and old comets whose volatiles have evaporated (the latter may still be largely ice)."</i><br /><br />Ummm...<a href="http://en.wikipedia.org/wiki/Volatiles" rel="nofollow">water is a volatile chemical for planetological purposes</a>. If the volatiles have evaporated, there ain't no ice left.Tonyhttp://blogs.echofiveecho.comnoreply@blogger.comtag:blogger.com,1999:blog-7494544263897150929.post-85618788609606165372010-11-17T20:23:00.777-08:002010-11-17T20:23:00.777-08:00Unproven, not impossible. There are 85 near-earth ...Unproven, not impossible. There are 85 near-earth comets as of June 1 this year (<a href="http://neo.jpl.nasa.gov/stats/" rel="nofollow">NASA stat link</a>), and the asteroid categories include both rocks and old comets whose volatiles have evaporated (the latter may still be largely ice). More detailed composition data is required before we could say one way or the other. (Incidentally, this is one of the reasons I'm excited by the prospect of more NEO missions in the near future.)<br /><br />I share your skepticism in the near-term, though. We really shouldn't plan on getting any materials from NEOs in any real quantities. If we find a few iceballs within easy reach, great, but it's better for the near term to be pessimistic about it.Raymondhttps://www.blogger.com/profile/18103471451043461302noreply@blogger.comtag:blogger.com,1999:blog-7494544263897150929.post-58878772019763491242010-11-17T20:12:42.281-08:002010-11-17T20:12:42.281-08:00Raymond:
"There are NEO objects which may co...Raymond:<br /><br /><i>"There are NEO objects which may contain useful amounts of water..."</i><br /><br />I include those in the same category of the unproved unproved water on the Moon. Even if the water is there, it isn't all that much. One estimate that gets tossed around a lot is a billion gallons in the crater where they dumped LCROSS. That's only 3,000 acre-feet. Which would supply 12,000 households for a year, even by stricter Desert Southwest conservation standards. And, oh yeah...that's after you land thousands of tons of collection and refining equipent to make use of it.<br /><br />That's the problem with lunar/NEO/cometary water -- the snake oil salesmen who try to convince you it will work just handwave away all of the real world engineering. Well, the ones who know any engineering -- most of them are simply ignorant idealists.Tonyhttp://blogs.echofiveecho.comnoreply@blogger.comtag:blogger.com,1999:blog-7494544263897150929.post-87210740920393061022010-11-17T17:15:07.053-08:002010-11-17T17:15:07.053-08:00Tony:
"If our propulsion technology is nucle...Tony:<br /><br /><i>"If our propulsion technology is nuclear-thermal with water remass, then cometary ice is essentially unreachable. The energy to rendezvous an ice mining/refining operation with a comet, then slow any mined/refined ice back down to manageable orbital velocities is beyond that technology's parctical capabilities."</i><br /><br />Not necessarily. There are NEO objects which may contain useful amounts of water within the delta-v of <i>chemfuel</i>, much less nuke-thermal. But we already have ion engines of a couple different types, and VASIMR's looking good. no reason to assume we're limited by nuke-thermal delta-v.<br /><br />I still don't think habitats made from large amounts of water lying about in space are feasible or sensible in the next century or two, so I'm not really disagreeing with you on this one. By the time such an operation is economical, wouldn't we have proven by definition that we don't really need it? (I mean, it could be useful for propellant you don't have to bring up the well, but whole habs?)Raymondhttps://www.blogger.com/profile/18103471451043461302noreply@blogger.comtag:blogger.com,1999:blog-7494544263897150929.post-52238020760160096012010-11-17T16:35:16.013-08:002010-11-17T16:35:16.013-08:00"What is the radiation picture for prolonged ..."What is the radiation picture for prolonged exposure? For example, supposing two ships with 100 MW drives, how much distance must they maintain in formation during a 3 month mission? With the drive shut down, how long can it be parked alongside another ship or station."<br /><br />Water is your friend. Water stops neutrons, and the water-density plastic tanking stops x/gamma. Plus you have decent distances for that part of the rad-health equation (time-distance-shielding).<br /><br />A US nuclear-powered submarine uses (according to wikipedia) a reactor in the ~150MW power range. The reactor itself sits in about 25m^3 of water. Then there's a couple water tanks, each about 3m thick (yes, it's heavy, but water is too useful to not have *lots* onboard ship). <br /><br />Total dose from living ~200 feet from an operating nuclear reactor for several months? Zero, if everything works the way it's supposed to.<br /><br />You want lots of water for life support, shielding, and catastrophic-emergency remass.Scotthttps://www.blogger.com/profile/08876828579688122237noreply@blogger.comtag:blogger.com,1999:blog-7494544263897150929.post-47173016966827281862010-11-17T16:12:20.628-08:002010-11-17T16:12:20.628-08:00"A courtroom. Not primarily for criminal case..."A courtroom. Not primarily for criminal cases, but a lot of civil things. Mining claims, lawsuits, and the like. It may be more informal than our current system- more along the lines of a Judge Judy at first."<br /><br />Nah. Captain's Mast. put a green tablecloth down and read someone the riot act, bust them back a couple paygrades, and then cost them a couple month's pay.<br /><br />It's worked for about 100 years here on earth, even in the submarine force. It also doesn't happen very often.<br /><br />Once you get to the point of needing to define mining claims, then you'd need someone (poor soul) dedicated to the job. It's not like the US Bureau of Land Management is going to be out there!Scotthttps://www.blogger.com/profile/08876828579688122237noreply@blogger.comtag:blogger.com,1999:blog-7494544263897150929.post-13346233430349983962010-11-17T15:58:38.429-08:002010-11-17T15:58:38.429-08:00Thucydides:
"The Neofuel site..."
Is n...Thucydides:<br /><br /><i>"The Neofuel site..."</i><br /><br />Is nonsense.<br /><br />If our propulsion technology is nuclear-thermal with water remass, then cometary ice is essentially unreachable. The energy to rendezvous an ice mining/refining operation with a comet, then slow any mined/refined ice back down to manageable orbital velocities is beyond that technology's parctical capabilities.<br /><br />And no, I don't believe in plentiful enough lunar water ice to mkae a difference, so let's forget that part of the discussion right now.Tonyhttp://blogs.echofiveecho.comnoreply@blogger.comtag:blogger.com,1999:blog-7494544263897150929.post-61645686725608659062010-11-17T10:57:27.860-08:002010-11-17T10:57:27.860-08:00Humans are rather time sensitive, so for short tri...Humans are rather time sensitive, so for short trips (like to the Moon), high thrust, low ISP drives are probably the way to go. After all, chemical rockets took us to the Moon and back using 1960's technology with a trip time of three days, and it ony took that long because the Moon's gravitational field is pretty weak and a fast flyby would need a much more powerful engine and more fuel to slow down and enter Lunar orbit.<br /><br />Once we make the decision to head out to deep space (NEO's, Mars, the gas giants), then low thrust, high ISP drives become more useful since they can get you there much faster (VASMIR to Mars in 39 days, and IEC fusion [if it can be made to work] to the outer planets in about 2 months according to Robert Brussard). Flocks of solar sails or solar panels attached to ion drives will also work out to the asteroid belt at least.<br /><br />Low tech, low cost "homes" can be made out of tire shaped bladders filled with water (and water seems to be everywhere, even on the Moon, which seems a bit weird after being told the moon was stripped of volatiles during formation. Clearly we have a lot to learn). The Neofuel site has the basic outline, a 100m dia. donut can be made with a 12 ton bladder and 8000 tons of water (houses 100) while a larger 215 m dia ship can hold 1900 people and weighs in at 40,000 tons). Moving a beast like that would probably take a low ISP high thrust drive for breaking orbit, terminal manouevres and a low thrust, high ISP drive for "cruise" to get anywhere in a reasonable time frame.<br /><br />Since the drive machinery would be in the middle of the donut hole, you also have your reactor/power supply with you at all times, or could swap it out/ditch it if needed, or were settling down as a space station.Thucydideshttps://www.blogger.com/profile/09828932214842106266noreply@blogger.comtag:blogger.com,1999:blog-7494544263897150929.post-66610561983888894452010-11-17T09:05:00.667-08:002010-11-17T09:05:00.667-08:00Raymond:
"I'm not exactly sure how you&#...Raymond:<br /><br /><i>"I'm not exactly sure how you'd optimize an engine like VASIMR..."</i><br /><br />I'm not either, but, in principle, any engineering artifact that can be more narrowly optimized towards a performance regime can be made more efficient.Tonyhttp://blogs.echofiveecho.comnoreply@blogger.comtag:blogger.com,1999:blog-7494544263897150929.post-74342646686865421112010-11-16T19:25:36.711-08:002010-11-16T19:25:36.711-08:00Nuke thermal may make a useful ferry tech and/or s...Nuke thermal may make a useful ferry tech and/or slow interplanetary cargo tech, though. It's at least an order of mag smaller than nuke electric by specific power - no radiators, generators or ion engines, and the shielding can be lessened due to the exposure times being measured in hours instead of months. It could also be used bimodal, allowing a small ion engine to slowly return to low orbit (with substantially lessened power levels, and thus radiation). I think it might even be a preferred crew ferry drive tech for the above.Raymondhttps://www.blogger.com/profile/18103471451043461302noreply@blogger.comtag:blogger.com,1999:blog-7494544263897150929.post-78423665209670089252010-11-16T19:12:44.921-08:002010-11-16T19:12:44.921-08:00Nuclear thermal may fall between stools.Nuclear thermal may <i>fall</i> between stools.Rickhttps://www.blogger.com/profile/16932015378213238346noreply@blogger.comtag:blogger.com,1999:blog-7494544263897150929.post-73891066457710636592010-11-16T19:10:36.561-08:002010-11-16T19:10:36.561-08:00Yes. From a delta v point of view, everything from...Yes. From a delta v point of view, everything from geosynch to translunar space and lunar orbit is one fare zone, so to speak. From LEO, assuming Oberth boot, it is 3.2 km/s to Earth escape, 3.9 km/s to low lunar orbit, and 4.1 km/s to geosynch. <br /><br />High ISP drives are nominally less efficient in this envelope because their low acceleration precludes Oberth boot. However, their fuel economy is so much better that they are preferable, except perhaps for human travel. (Van Allen belts and seat time.)<br /><br />Nuclear thermal may between stools. The specific impulse is 2-3x chemfuel, and acceleration is sufficient for Oberth boot. But you need a reactor with heavy shielding for human travel, and you cannot use aerobraking for the return to LEO - nuclear meteors in the upper atmosphere are a VERY BAD idea.Rickhttps://www.blogger.com/profile/16932015378213238346noreply@blogger.comtag:blogger.com,1999:blog-7494544263897150929.post-44573207871823750532010-11-16T17:58:57.336-08:002010-11-16T17:58:57.336-08:00Tony:
I'm not exactly sure how you'd opti...Tony:<br /><br />I'm not exactly sure how you'd optimize an engine like VASIMR, given its ability to essentially self-optimize, but I can certainly see the powerplant being tailored to orbital service. Say, Rick's solar butterflies or Milo's fully-shielded nukes. Maybe even nuke thermal (if the rads aren't that bad) or solar sails (if the tricky orbits can be reliably used). <br /><br />(Now that I think about it, I can see nuke thermal being employed for cargo on slower orbits, given it fits a little better with the disposable stage paradigm. Solar sails may also be better suited for interplanetary cargo, at least on the outbound leg.)<br /><br />The other consideration is that orbital ferries are also well-suited for Lunar travel (at least to Lunar orbit, anyways). Their very existence may substantially reduce the cost of a Lunar base. If we already have the transport infrastructure pretty well in place, would a Lunar base be worth the (now lessened) marginal cost?Raymondhttps://www.blogger.com/profile/18103471451043461302noreply@blogger.comtag:blogger.com,1999:blog-7494544263897150929.post-43817091241518240802010-11-15T23:22:04.266-08:002010-11-15T23:22:04.266-08:00Raymond:
"So, if we take nuke-electric inter...Raymond:<br /><br /><i>"So, if we take nuke-electric interplanetary craft as too dangerous to park in LEO, requiring ferries (presumably still high-ISP drives, but possibly lower-performance than interplanetary versions) to move cargo and people to and from..."</i><br /><br />It's not just the nuclear risk that might motivate parking in high orbit. There's also the question of propulsion optimization. Even with something like VASIMR, performance optimization is still possible. So in very much the same manner as staging during Earth to orbit launch offers the opportunity to use upper stage engines optimized for the vacuum operation, parking in high orbit keeps the interplanetary spacecraft out where its engines can be optimized more towards the interplanetary environment. The inter-orbit ferries would have engines optimized for their task as well. Might be worth doing for that reason alone.Tonyhttp://blogs.echofiveecho.comnoreply@blogger.comtag:blogger.com,1999:blog-7494544263897150929.post-14514785830799055632010-11-15T18:19:46.490-08:002010-11-15T18:19:46.490-08:00For prolonged exposure, you need to take into acco...For prolonged exposure, you need to take into account the fact that some types of radiation are more effective at causing chronic symptoms than others. Correcting for this gives you a dose in units of Sv - for neutrons this is assumed to mean multiplying by 10. The galactic cosmic ray dose in space varies from about 400 mSv/year to about 900 mSv/year. This corresponds to 40 mGy/year to 90 mGy/year. For a 100 MW unshielded reactor, my previous assumptions give a dose of 500/r^2 Gy/s, where r is the distance from the source to the target. From this we can solve for the distance that will reduce the neutron dose to about the same as the cosmic ray dose (let's pick 500 mSv/year), and this turns out to be 178 km. So a few hundred km separation will allow two craft to fly in formation safely using their cosmic ray shielding. If the reactors are shielded, this distance can be decreased. 8 cm of borated HDPE, for example, would allow them to safely approach within a few hundred meters.<br /><br />The radiation from a shut-down reactor depends on how much time has passed since it has been shut down and for how long it had been running. A very rough estimate would put the gamma radiation after 10 days of inactivity from a reactor that had been running for a month at about one billionth of the original power level and the neutron radiation as negligible. For a 100 MW reactor in which we neglect any shielding 9including self-shielding) at 10 meters distance, you are looking at something on the order of a microgray per second, or about 100 times the galactic cosmic ray dose rate. If the reactor had been operating for several years without refueling, you might be getting an order of magnitude or two larger dose rate. Again, shielding will reduce the dose.Lukehttps://www.blogger.com/profile/09617890536562434320noreply@blogger.comtag:blogger.com,1999:blog-7494544263897150929.post-42452911604149512732010-11-15T17:13:48.295-08:002010-11-15T17:13:48.295-08:00What is the radiation picture for prolonged exposu...What is the radiation picture for prolonged exposure? For example, supposing two ships with 100 MW drives, how much distance must they maintain in formation during a 3 month mission? With the drive shut down, how long can it be parked alongside another ship or station.<br /><br /><br />On ferries, human passengers, etc., may be taken up by chemfuel (which could mean simply refueling the shuttle, or launching on a bigger booster). <br /><br />A fast trip, instead of spiraling up or down, gets passengers through the Van Allen belts much more quickly, and also means they can make the trip in airliner style seats. The slow spiral requires a higher habitability level.<br /><br /><br />On using semi-retired interplanetary habs in orbit, my premise is that interplanetary missions require a <i>really</i> high reliability margin, no failures requiring any material support whatever for a year and upwards. But failures that would endanger a mission a year from Earth may be trivial if you are two weeks from a replacement part.<br /><br />Practical engineering considerations may rule this out, but it has a cousin, ships that are simply obsolescent, particularly the drive bus. <br /><br />If you have an older generation hab, still in parameters, with an obsolescent drive bus, it may not be worth mating to a new bus for interplanetary service, but still available for orbital service if you have use for it.<br /><br />The underlying question is whether you have any orbital work force that needs hotel accommodations. If everyone in orbital space can conveniently bunk at night aboard a shuttle, ferry, or deep space ship in parking orbit, you don't need a hab pod as an orbital hotel. But if this does not fit your work cycle, you will need something.Rickhttps://www.blogger.com/profile/16932015378213238346noreply@blogger.comtag:blogger.com,1999:blog-7494544263897150929.post-63700269052203394942010-11-15T16:36:10.940-08:002010-11-15T16:36:10.940-08:00The thing about orbital stations is that they can ...The thing about orbital stations is that they can be used for many different missions; these missions(scientific, industrial, commercial, logistics, etc), can be performed simutaniously and so stations need not depend on interplanetary spacecraft operations so much. And that's one orbiting Earth. One orbiting Callisto (for example), might be used for support of not only the exploration bases on the moon's surface, as well as on Europa and Ganymeade, and be the focal point for studying the radiation enviornment, magnetosphere, and Jupiter's atmosphere; a single point for cargo and personnel transfer from Earth, instead of half-a-dozen. So, yes, once you go beyond the narrow view of what a station could be used for, or what it should be used for, and look at all the reasons a station could be used for, then they become much more attractive.<br /><br />FerrellAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-7494544263897150929.post-26654236312394318352010-11-15T16:32:37.208-08:002010-11-15T16:32:37.208-08:00For an orbital ferry for a planet with a strong ma...For an orbital ferry for a planet with a strong magnetic field, you could use electrodynamic tethers to move cargo and passengers without expending propellant.Lukehttps://www.blogger.com/profile/09617890536562434320noreply@blogger.com