Date: Thu, 24 Dec 92 05:06:40 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V15 #590 To: Space Digest Readers Precedence: bulk Space Digest Thu, 24 Dec 92 Volume 15 : Issue 590 Today's Topics: Acceleration, cats... aerospikes Article on DC asteroids beyond Jupiter Biosphere 2 update I thinI see our problem. (Was Re: Terminal Velocity of DCX? Pilots must be stupid? (Re: DC vs Shuttle capabilities SSTO vs. 2-Stage SSTO vs. 2 Stage Stupid Shut Cost arguements (was Re: Terminal Velocity of DCX? (5 msgs) The Appendix? (Re: Acceleration, cats...) The Real Justification for Space Exploration Welcome to the Space Digest!! Please send your messages to "space@isu.isunet.edu", and (un)subscription requests of the form "Subscribe Space " to one of these addresses: listserv@uga (BITNET), rice::boyle (SPAN/NSInet), utadnx::utspan::rice::boyle (THENET), or space-REQUEST@isu.isunet.edu (Internet). ---------------------------------------------------------------------- Date: Wed, 23 Dec 1992 18:46:54 GMT From: Josh 'K' Hopkins Subject: Acceleration, cats... Newsgroups: sci.space pgf@srl03.cacs.usl.edu ("Phil G. Fraering") writes: >Anyone here seen that special they did on TV a while back, about >how some cats have fallen from ten or twenty stories and sometimes >survived (don't try this at home! don't try it with a cat! and especially, >it doesn't work well with humans!)? >What I want to know is, how the ability to fall from 100-150 feet >up was _selected for_ by evolution. It implies that they went through >a period of development where cats that could do that were outcompeting >cats that weren't, to the extent that a large number of cats today can >do it. >Especially since this isn't something that can be done gradually: >the adaptations don't help in falls of 30-60 feet, or much higher than >somewhere around 100 feet (I think)... I'm not a biologist or even a cat owner but what the hell. This is better than the Terminal Velocity thread. Two things come to mind. First, you can't blame everything on evolution. The apendix comes to mind. Some things are around simply because they weren't selected against. Second, cats being hunters and able to climb trees, they must have had some way of getting down before they invented firemen. Jumping sounds like a possibility. I believe that the constraint on hights is not so much a question of shock absorbing ability but one of coordination. The test I believe you are refering to was studying just why it is that "cats always land on their feet." If you toss one of the second story window they don't have time to twist into the right position. A higher fall may sound more dangerous but it gives the cat time to get into landing position. Thus it's actually safer. One of these days, cats will have to adapt to space so maybe there is some value to this post. Probably not. -- Josh Hopkins jbh55289@uxa.cso.uiuc.edu Ho^3 !=L ------------------------------ Date: Wed, 23 Dec 1992 19:59:12 GMT From: "Edward V. Wright" Subject: aerospikes Newsgroups: sci.space In <1992Dec21.193604.28757@eng.umd.edu> sysmgr@king.eng.umd.edu (Doug Mohney) writes: >Contrast this with one (or more) flights out of Nevada or White Sands which may >or may not be significant (helps if you've been running up and back to LEO for >a while as a regular habit) and kicking out the sat on one of those runs. Well, if they (whoever "they are") don't know your flight is "significant" enough to shoot down, why are you in a hurry to reenter? >The cheap-sat may be in a predictable orbit, but you are now faced with >detecting it without the benefit of CNN coverage. If they can't detect a cheapsat without CNN coverage, how can they detect the launch vehicle? >Now, unless you have information from umm.. SPACETRACK? in NORAD, you have to >pick cheap-sat out of all the other man-made objects in orbit via some optical >means (hope it's not a cloudy night, but that cuts both ways) or with radar. Anyone who has an operational ASAT must, by definition, have some means of targeting. ------------------------------ Date: 23 Dec 92 18:52:10 GMT From: Paul Dietz Subject: Article on DC Newsgroups: sci.space The Dec. 1992 issue of Mechanical Engineering has a 4 page cover story on the Delta Clipper. It has a few details I had not seen before. Can someone explain in more detail Aerojet's proposal for the DC-Y, the "integrated modular platelet engine"? The description in the article was a bit too terse. Paul F. Dietz dietz@cs.rochester.edu ------------------------------ Date: 23 Dec 92 18:00:24 GMT From: Greg F Walz Chojnacki Subject: asteroids beyond Jupiter Newsgroups: alt.folklore.urban,sci.space From article , by jfurr@polaris.async.vt.edu (Joel K. Furr): > In article <1992Dec22.185915.27317@hpcvaac.cv.hp.com> billn@hpcvaac.cv.hp.com (bill nelson) writes: >>dj@ekcolor.ssd.kodak.com (Dave Jones) writes: >>: bill nelson (billn@hpcvaac.cv.hp.com) wrote: > [incipient flamage] >> >>The statement was asteroid - not planetoid. The asteroids originate in the >>asteroid belt. It is doubtful if any of them could be perturbed enough to >>reach the orbit if Neptune. >> [emergent flamage] Although it might seem like I'm paying out rope here, I'm curious about the usage of the terms "asteroid" and "planetoid." Bill, since yours is the first time I saw the distinction made, care to define these? (I hope it's more than asteroids being those things that lie where asteroids were first discovered.) THanks. Greg ------------------------------ Date: 23 Dec 92 16:52:35 GMT From: Tim McCaffrey Subject: Biosphere 2 update Newsgroups: sci.space Since B2 gets most (all?) of its power from solar, through the glass, I just gotta ask the obvious question: Does anybody/anything clean the windows? (outside) Tim McCaffrey ------------------------------ Date: Wed, 23 Dec 1992 16:58:35 GMT From: "Edward V. Wright" Subject: I thinI see our problem. (Was Re: Terminal Velocity of DCX? Newsgroups: sci.space In strider@clotho.acm.rpi.edu (Greg Moore) writes: > In reality it sounds more like you are talking about DC-10, >DC-12, etc. > Unless you are saying that a 747 is the same plane as a DC-3 >was. > If your claims are about 50 years from now, or even 20 >eyars from now, I'll buy them. I think it would do you a world of good to go out to your local airport and look around. Do you have any idea how many DC-3s are still flying? After 50 years? And the 747, which you cite as an example of a modern airplane, is well over 20 years old! ------------------------------ Date: Wed, 23 Dec 1992 17:02:55 GMT From: "Edward V. Wright" Subject: Pilots must be stupid? (Re: DC vs Shuttle capabilities Newsgroups: sci.space In strider@clotho.acm.rpi.edu (Greg Moore) writes: >>You can walk from one place to another carrying a four-ton >>cargo container? On Earth? I doubt it. > Carry it while walking? no, but I can drive it. If you have a flat tire? See, for every "greater difficulty" you can think of in space, I can think of one on Earth. > Again, I think I see were we are differing. See my other >post on timeframes. But to recap, I agree, after a couple thousand >more hours of EVA time, we'll have a lot more down. If the cost of putting one man into space was $50,000, instead of $5,000,000, you'd be able to rack up a thousand man-hours of EVA time pretty fast. >A diver can swim back. Or, with enough air (which they should >always have) resurface. Not if they're SEALs in a combat zone. Or cave divers. Or under ice. Or working in an underground sewer system. All of which are done routinely today. >>What makes you think a DC-1 can't accomplish a hard docking. >> > I wasn't aware that it could. This I understand would >have to be an added capability? HOw does it dock? through the >nose? or along the side? The McDAC illustration shows it docked alongside. I'm sure the docking adapter would be an added capability, carried in the cargo bay. Why carry it along on flights where you don't need it? If you consider this a problem, well, the Shuttle's docking adapter works the same way. ------------------------------ Date: Wed, 23 Dec 1992 17:07:00 GMT From: Bruce Dunn Subject: SSTO vs. 2-Stage Newsgroups: sci.space The point has been made that using the DC-1 as an upper stage of a two-stage vehicle adds the complication of mating the two vehicles. I feel that this is not likely to be a very time consuming job, but am willing to listen to any evidence. I think that the closest analogy might be the mating of a Shuttle to its carrier aircraft, which is done on a routine basis. I don't know if the current mounting allows in-flight separation, but the mounting used for the Enterprise glide tests certainly did. Does anyone have information on how long it takes and how many people it takes to put the Shuttle on the carrier aircraft? The point has also been made that the advantages of the two stage system are negated if the booster cannot return to the launch site. Flyback boosters, with wings, have been assumed in many hypothetical two-stage systems (and indeed a winged fly-back variant of the Saturn first stage was examined as a possible booster early in the design process for the Shuttle). In the case of the DC-1 first stage, I have been assuming no wings and only limited aerodynamic maneuverability (similar to that of the DC-1). To examine what would happen if the booster flight were ***entirely*** vertical, I have run a stepwise numerical simulation on a spreadsheet. The results are as follows: (rounded numbers) Assumptions: Booster Total Mass 1000 tons Booster Ascent Propellant 800 tons Booster Isp 300 Booster Initial acceleration 1.5 g DC-1 Total Mass 500 tons Payload 58 tons Results: Total Booster Burn Time 100 sec Total gravity losses 980 m/s^2 Booster Altitude at Burnout 46 km Velocity at Burnout 1190 m/s^2 Coasting Height 120 km The "coasting height" is what the DC-1 (and the booster) will get to if there are no further rocket burns. Since the DC-1 has enough vertical velocity from the booster to keep it clear of the atmosphere for some minutes, it can then perform its burn horizontally and avoid further gravity losses. The booster of course will drop right back towards the launch site. The above picture is an over simplification of the process, but I think that the general idea is clear. If there is anyone who has software which models ascent trajectories for launchers, it would be interesting to see proper calculations for such a "bent" ascent trajectory (vertical ascent for a first stage, followed by a largely horizontal burn from a second stage). -- Bruce Dunn Vancouver, Canada Bruce_Dunn@mindlink.bc.ca ------------------------------ Date: 23 Dec 92 20:08:27 GMT From: "Edward V. Wright" Subject: SSTO vs. 2 Stage Newsgroups: sci.space In <18822@mindlink.bc.ca> Bruce_Dunn@mindlink.bc.ca (Bruce Dunn) writes: > Agreed. Failure of second and third stage engines of conventional >launchers to ignite after staging has historically been a common cause of >launch failures. However, I presume that the DC-1 will have the capability >of surviving at least 1 engine failure when at near maximum fuel load >(otherwise failure of any one out of multiple engines would cause a crash in >the period immediately following an SSTO takeoff). However, you've overloaded the DC-1 to get that 5x payload capacity you talk about. It's going to be over max takeoff weight. > I grant that no amount of engine out capability will help a DC-1 if >it separates from the booster and none of the engines fire because of a fuel >problem. Or if you have negative separation, or separation followed by a collision, or several other scenarios you need to worry about. The problems of staging are not nearly as trivial as you make them out. ------------------------------ Date: Wed, 23 Dec 1992 16:39:31 GMT From: "Edward V. Wright" Subject: Stupid Shut Cost arguements (was Re: Terminal Velocity of DCX? Newsgroups: sci.space In <9gt204c@rpi.edu> strider@clotho.acm.rpi.edu (Greg Moore) writes: > I thought you said that McDac or SDIO was going to treat >development costs of DC-1 as sunk costs. That depends on exactly who funds DC-1, doesn't it? SDIO has said that it won't fund that part of the program, although it could change its mind. The Air Force or some other agency might be interested -- too early to say. McDonnell Douglas isn't in great shape right now, so I don't think there's much chance they could develop it as a commercial project without external funding. A joint venture, maybe, like Boeing's 777 venture with the Japanese? If it's done as a commercial project, the R&D will have to be recouped. McDonnell Douglas is in business to make money. This doesn't appear too hard. Suppose the development program costs $1.5 billion. If McDAC can build DC vehicles for $100 million after than, and sell them for $200 million, it can pay off the R&D on the first 15 copies and be making a profit after that. (I'm ignoring interest, which would bump the figures up a little bit, but not a lot.) It's also possible McDAC might find a customer that wants just the first few vehicles off the assembly line and wants them badly enough to foot the bill for the entire R&D program. This, actually, isn't uncommon with high-tech projects, though probably only the Federal government has the money to do it on this scale. >As for amortization of the orbiter, the same rule applies to that >as any aircraft or spacecraft, including, DC-1. The more you >fly it, the less this matter. Right now, if you stopped all flights, >you could argue this cost (excluding interest) is about $150 million >a flight. (10 flights/orbiter, $1.5 Billion per orbiter). This >number will shrink. That is by no means certain. There's a good chance someone else will fly an orbiter into the ground in the next few years and the whole fleet will be grounded permanently. And while the increasing number of flights tends to bring the average cost down, Shuttle improvement programs tend to push it back up again. ------------------------------ Date: 23 Dec 92 10:29:52 From: Steinn Sigurdsson Subject: Stupid Shut Cost arguements (was Re: Terminal Velocity of DCX? Newsgroups: sci.space In article <1992Dec23.132824.14131@iti.org> aws@iti.org (Allen W. Sherzer) writes: In article <9gt204c@rpi.edu> strider@clotho.acm.rpi.edu (Greg Moore) writes: > I thought you said that McDac or SDIO was going to treat >development costs of DC-1 as sunk costs. Or is that just DC-X (in >which case, what exactly does that mean?). DCX and DCY are proof of concept vehicles which the government is paying for. Nither are operational vehicles. DC-1 will likely be a very different sort of craft altogether. It will incorporate lessons learned on DCY, it >Right now, if you stopped all flights, >you could argue this cost (excluding interest) is about $150 million >a flight. (10 flights/orbiter, $1.5 Billion per orbiter). You left out the $34 billion (in 86 $$) development costs which must be amortized. Does this include the cost of the Enterprise? If so, why is it not a sunk cost as you argue the DC-Y should be? Does it include construction of wind tunnels, the (Grumman?) glide simulator and operations thereof? What about the software development costs for doing a lot of the aerodynamic simulations, are they shuttle costs or generic NASA costs that would have been incurred regardless. You've said you want to bill all manned space program costs to the shuttle, does that include suit development? If so, what are the DC personnel going to wear for EVA? Hell, will a DC groundstaff include any janitors? Haven't seen those costed... (and if not, who will mop up spills? ;-) I think you are quite inconsistent in how you assign costs to the DC and Shuttle. For instance you explicitly said tank farm operation for LOX and LH2 should not be included, only the marginal cost of loading each DC - yet you necessarily inlcude those costs for KSC operations. Similarly your costs do not include software support (is the DC going to use JPL or JSC software for trajectory projecting? are those sunk costs? Will they use whatchamcallits database for LEO objects to avoid collisions, and will the DC then pay for the radars that do the tracking? Amortised over how many flights?). You also haven't included any cost estimates for ground support? Will there be TDRS(type) links in-orbit? Will it use existing groundstations and satellites (with sunk costs) or build its own (with sunk development costs!). The DC is a really nice concept, I hope it works, but at least try to be fair in assigning costs when you compare it with the shuttle! | Steinn Sigurdsson |I saw two shooting stars last night | | Lick Observatory |I wished on them but they were only satellites | | steinly@lick.ucsc.edu |Is it wrong to wish on space hardware? | | "standard disclaimer" |I wish, I wish, I wish you'd care - B.B. 1983 | ------------------------------ Date: 23 Dec 92 19:13:06 GMT From: "Allen W. Sherzer" Subject: Stupid Shut Cost arguements (was Re: Terminal Velocity of DCX? Newsgroups: sci.space In article steinly@topaz.ucsc.edu (Steinn Sigurdsson) writes: > You left out the $34 billion (in 86 $$) development costs which must > be amortized. >Does this include the cost of the Enterprise? When Boeing built the first 747 it was a non-flying test aircraft just like Enterprise in most important respects. Since Boeing didn't count this first 747 as a sunk cost (they would be bankrupt if they did) I don't think Enterprise should be considered a sunk cost. >If so, why is it not a >sunk cost as you argue the DC-Y should be? DC-Y is a proof of concept for a very limited market (SDI deployment). The DC-1 will likely be a very different vehicle and will be a new one for all practical purposes. That cannot be said for Enterprise. >Does it include >construction of wind tunnels, the (Grumman?) glide simulator and >operations thereof? Since Boeing charges those things to development and passes those on to customers, I think NASA should as well for its operational vehicles. >What about the software development costs for >doing a lot of the aerodynamic simulations, Boeing also writes software for aerodynamic simulations when it developes aricraft. The cost of this is included in development and is passed on to customers. NASA should as well for its operational vehicles. Fair enough? >You've said you want to bill all manned space program costs to the >shuttle, No, that is not what I said. That is what Dennis put into my mouth. >does that include suit development? If so, what are the DC >personnel going to wear for EVA? Well, I think they should pay their fair share of the development costs for whatever suit they use. >I think you are quite inconsistent in how you assign costs to >the DC and Shuttle. I disagree. However, it is a minor point since if you use the same rules (pick any you like) DC comes out far far ahead of Shuttle. In fact, you could amortize DC-Y development, DC-X development, and DC-1 development and it STILL comes out cheaper than the operational costs of Shuttle (~$6,000 per pound for DC vs $10,000 per pound for Shuttle). All three efforts cold be funded with the interest you would get by putting Shuttle development money in the bank at 5%. >For instance you explicitly said tank farm >operation for LOX and LH2 should not be included, only the marginal >cost of loading each DC No, I have never said that. I think DC will get fuel from the same source that airliners get fuel. American Airline doesn't produce its own fuel, not do they get it at marginal cost. Instead they buy it from suppliers who include the cost of tank farms in the price they charge. DC will be no different. Allen -- +---------------------------------------------------------------------------+ | Allen W. Sherzer | "A great man is one who does nothing but leaves | | aws@iti.org | nothing undone" | +----------------------122 DAYS TO FIRST FLIGHT OF DCX----------------------+ ------------------------------ Date: 23 Dec 92 12:14:15 From: Steinn Sigurdsson Subject: Stupid Shut Cost arguements (was Re: Terminal Velocity of DCX? Newsgroups: sci.space In article <1992Dec23.191306.6705@iti.org> aws@iti.org (Allen W. Sherzer) writes: Sheesh, that was fast! Doesn't anyone break for holidays any more? In article steinly@topaz.ucsc.edu (Steinn Sigurdsson) writes: > You left out the $34 billion (in 86 $$) development costs which must > be amortized. >Does this include the cost of the Enterprise? When Boeing built the first 747 it was a non-flying test aircraft just like Enterprise in most important respects. Since Boeing didn't count this first 747 as a sunk cost (they would be bankrupt if they did) I don't think Enterprise should be considered a sunk cost. A gliding body with no engines and no heat shield is comparable to the operational system? And are you sure that the first 747 didn't fly? Even the first 707 flew and that was a far more groundbreaking test article (despite the B-47 and B-52 which sunk some of the development costs - and it still crashed before taking off!). Henry, you there to arbitrate? >If so, why is it not a >sunk cost as you argue the DC-Y should be? DC-Y is a proof of concept for a very limited market (SDI deployment). The DC-1 will likely be a very different vehicle and will be a new one for all practical purposes. That cannot be said for Enterprise. >Does it include >construction of wind tunnels, the (Grumman?) glide simulator and >operations thereof? Since Boeing charges those things to development and passes those on to customers, I think NASA should as well for its operational vehicles. Really, did Boeing pay for the development of winglets (those little dinky wingtip things the latest models have)? Did they pay for the aerodynamic studies of ducted vs unducted fans? Did they even pay for the development costs of the basic jetliner airbody designs or did they sink it to military contracts? [as I understand it, the developments I mentioned above were largely done by NASA, under its first "A" - and, no, I don't think those studies included to any "real" science [sic] - including some work done at NASA Ames using the windtunnel that did the shuttle 1/3 scale simulations. >What about the software development costs for >doing a lot of the aerodynamic simulations, Boeing also writes software for aerodynamic simulations when it developes aricraft. The cost of this is included in development and is passed on to customers. NASA should as well for its operational vehicles. Fair enough? Nope, not when a lot of the algorithm development is done by NASA and Universities under NASA contracts and then handed over to the aerospace companies at below cost (or for free). >You've said you want to bill all manned space program costs to the >shuttle, No, that is not what I said. That is what Dennis put into my mouth. I thought you quoted a (Pike?) study saying $500 M per flight charging all costs to shuttle, $750 M if (sunk) development costs were included. Apologies if it was Dennis... >does that include suit development? If so, what are the DC >personnel going to wear for EVA? Well, I think they should pay their fair share of the development costs for whatever suit they use. Yeah, right. Is there still a line in the budget to recoup Apollo and Mercury sunk costs? Sometimes you just have to write some costs off as sunk and not try to recoup them... >I think you are quite inconsistent in how you assign costs to >the DC and Shuttle. I disagree. However, it is a minor point since if you use the same rules (pick any you like) DC comes out far far ahead of Shuttle. In fact, you could amortize DC-Y development, DC-X development, and DC-1 development and it STILL comes out cheaper than the operational costs of Shuttle (~$6,000 per pound for DC vs $10,000 per pound for Shuttle). All three Over how many flights??? At the moment, with zero flights the DC is inifintely more expensive than the shuttle! What flight rate and amortization period are you using? efforts cold be funded with the interest you would get by putting Shuttle development money in the bank at 5%. No, you'd have to use it for severance pay... >For instance you explicitly said tank farm >operation for LOX and LH2 should not be included, only the marginal >cost of loading each DC No, I have never said that. I think DC will get fuel from the same source that airliners get fuel. American Airline doesn't produce its own fuel, not do they get it at marginal cost. Instead they buy it from suppliers who include the cost of tank farms in the price they charge. DC will be no different. Again over how many flights to you propose to amortise the infrastructure for? What throughput will you guarantee whoever capitalises the tank farm construction and pays for operation? That will critically determine the cost. | Steinn Sigurdsson |I saw two shooting stars last night | | Lick Observatory |I wished on them but they were only satellites | | steinly@lick.ucsc.edu |Is it wrong to wish on space hardware? | | "standard disclaimer" |I wish, I wish, I wish you'd care - B.B. 1983 | ------------------------------ Date: 23 Dec 92 21:21:00 GMT From: "Allen W. Sherzer" Subject: Stupid Shut Cost arguements (was Re: Terminal Velocity of DCX? Newsgroups: sci.space In article steinly@topaz.ucsc.edu (Steinn Sigurdsson) writes: >A gliding body with no engines and no heat shield is comparable >to the operational system? It's called a structural test article. They are frequently built to test aspects of an aircraft design. >Really, did Boeing pay for the development of winglets (those little >dinky wingtip things the latest models have)? ... Look, if your trying to say that research has been done in the past and that research should be treated as a sunk cost, then you are partly correct. The concept is correct but the word is 'depreciated'. Sure there is lots of depreciated costs going into airliner development. Much of that does come from government funded research. I have no problem with that. You will note that I didn't say the money used to build the X-24, an important vehicle for Shuttle, should be charged to Shuttle. The fact remains however that we did spend $34 billion to develop Shuttle and that cost should be accounted for. If we are going to pick and choose what costs we include and which we don't then why not say Shuttle is free? >for the development costs of the basic jetliner airbody designs >or did they sink it to military contracts? To some extent I'm sure they did. This happens all the time however in the civilian world. The first signal processing chips where built for customers willing to pay development. They where then sold to whoever. The point is that unlike Shuttle, all costs where accounted for. >I thought you quoted a (Pike?) study saying $500 M per flight >charging all costs to shuttle, $750 M if (sunk) development costs >were included. Apologies if it was Dennis... That was Dennis misquoting Pike. Pike said that if you add up all the manned costs you get a figure of ~$750M. I claim the cost of a Shuttle flight to be $500M plus the then year development costs amortized over say, 20 years. I don't remember what that comes to but it is easially over a billion. This is the formula American uses to sell most tickets so I think Shuttle should do the same. I also insist on DC doing the same, I'm not giving it a free ride. > could amortize DC-Y development, DC-X development, and DC-1 development > and it STILL comes out cheaper than the operational costs of Shuttle > (~$6,000 per pound for DC vs $10,000 per pound for Shuttle). All three >Over how many flights??? At the moment, with zero flights the DC is >inifintely more expensive than the shuttle! Please let's be resaonable here. By your arguement every new vehicle is infinitely more expensive than existing ones and so shouldn't be built. >What flight rate and amortization period are you using? I just looked up the exact numbers. At 10 flights per year (roughly 80% the US MLV market) a DC-1 should (if it works) cost $2700 per pound. This is a third the cost of Shuttle and about 25% less than existing expendables. If flight rate goes to 12 a year then costs drop to about $2300 per pound. This assumes a $3B (twice McD's estimate) DDT&E cost over 10 years. Now if we amortize over 25 years we get $1890 (10 flights) to $1658 (12 flights) per pound. Again, this compares to $3900 for Titan III and $10,000 for Shuttle. This still leaves plenty of room for error. After development is amortized (which can happen with the existing market) costs drop to $100 to $500 per pound. Allen -- +---------------------------------------------------------------------------+ | Allen W. Sherzer | "A great man is one who does nothing but leaves | | aws@iti.org | nothing undone" | +----------------------122 DAYS TO FIRST FLIGHT OF DCX----------------------+ ------------------------------ Date: 23 Dec 92 18:55:47 GMT From: Paul Dietz Subject: The Appendix? (Re: Acceleration, cats...) Newsgroups: sci.space In article jbh55289@uxa.cso.uiuc.edu (Josh 'K' Hopkins) writes: > Two things come to mind. First, you can't blame everything on > evolution. The appendix comes to mind. Some things are around simply > because they weren't selected against. Actually, I was under the impression the appendix was thought to have some role in the immune system (say, for acting against GI infections). Given that appendicitis can be lethal, evolution *should* have gotten rid of it unless it had some compensating benefit. (Note followup.) Paul F. Dietz dietz@cs.rochester.edu ------------------------------ Date: Wed, 23 Dec 1992 20:02:40 GMT From: Ken Arromdee Subject: The Real Justification for Space Exploration Newsgroups: sci.space,talk.politics.space In article <1h9p9fINN6l3@transfer.stratus.com> det@phlan.sw.stratus.com (David Toland) writes: >It seems to me that all of these spinoff arguments, Malthusian >arguments, and "dinosaur killer" arguments miss the point. >Asking "why explore space?" is like asking "why feed the starving?", >"why create art?", or "why do basic science?" It all comes down to >basic human drives, and I would argue that the drive to explore is >just as basic as the drive to help, to create, or to learn. I would argue that there are a lot of other things that are basic human drives, some a lot less benign. (You can name your own examples.) We humans have the capability to decide to override our instincts when we can figure out that following them is not good for us. To claim that exploration is a basic drive is not a justification--if anything, it reduces space exploration to the human equivalent of lemmings running over a cliff. (No posts about staged lemming marches, please.) >When Sir Edmund Hillary was asked why he climbed Everest, he answered, >"Because it's there." The same answer is just as appropriate for why >we explore space -- because the entire universe is out there... If you must succumb to your animal instincts, go ahead. I suggest not using public money, taxed from me whether I want to support your instincts or not. If you're getting the money from me, you had better argue that the program is actually beneficial, not just that your personal instinct commands it. -- "the bogosity in a field equals the bogosity imported from related areas, plus the bogosity generated internally, minus the bogosity expelled or otherwise disposed of." -- K. Eric Drexler Ken Arromdee (arromdee@jyusenkyou.cs.jhu.edu, arromdee@jhunix.hcf.jhu.edu) ------------------------------ End of Space Digest Volume 15 : Issue 590 ------------------------------