Date: Sun, 16 Aug 92 14:56:58 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V15 #115 To: Space Digest Readers Precedence: bulk Space Digest Sun, 16 Aug 92 Volume 15 : Issue 115 Today's Topics: ACRV/Soyuz P # of Passengers (2 msgs) beanstalk in Nevada (2 msgs) Early Warning of missiles and meteors Energiya's role in Space Station assembly Fermi Paradox vs. Prime Directive Nasa small business programs Persied Shower Solar System Journal Star Trek (anti-)realism Weird circle-like things on shuttle map Whither a Lunar Base (was: Energiya's role in Space Station assem) 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: 15 Aug 92 14:39:45 GMT From: "Allen W. Sherzer" Subject: ACRV/Soyuz P # of Passengers Newsgroups: sci.space In article <14AUG199223295140@judy.uh.edu> seds%cspara.decnet@Fedex.Msfc.Nasa.Gov writes: >Allan you have still not addressed with numbers the propostion that the >Shuttle will become MORE useful as the return of large payloads grows more >common in the SSF era. The biggest payload identified is about 15K pounds. The only larger payload (LDEF) can be easilly broken up in LEO and individual experiments sent back with new ones added (saving launch costs). A simple return craft can be built to return these payloads in a suitable environment. Estimate the cost of this anyway you want. What you haven't addressed is why it is a good idea to waste billions now for payloads which aren't even on the horizion? >>In ten years of operation Shuttle has not come down in price very much. >What is your source for this statement Allan. The maximum flight rate for the >Shuttle is about one per month. T Total Shuttle spending has been going up but has leveled off recently. An arguement can be made that costs have come down if you include early flights but costs are now as low as they ever will be. >A ten launch per year rate is certainly possible now. That is a bit less than the one per month you quote above and also unrealistic. Ten flights has only been acheived one time and it ended with Chalenger. >Also I have >not heard any comments from you regarding the greaat increase in Shuttle >reliability and schedule. Since it achieves less reliability than commercial systems costing a fraction as much I don't think it is anything to boast about. Let's see it go on for a few years. >I wonder where all of these facilities are at. They certainly aren't at KSC. HL Delta would use Complex 37. As for Atlas, the report I mention does say that the additional six flights can be acheived. If I'm wrong, give me the cost of a new Atlas facility and I'll add it to my estimates. >Also, new clean rooms and payload integration facilities at these new >pads will have to be built. It ain't all there Allan. What isn't there is included in the estimated development costs. Like I said, the HL Delta designers know what they are doing. >McDonnell Douglas does not have the cash to pull this off. They offered to do it; I assume they know better than you if they have or can get the cash. >No one without a VERY deep pocket would dare operate on a services only basis >NONE of the worlds current launch providers operate on a service delivered or >no payment basis. None could justify this to stockholders. You are sadly mistaken. ALL the commercial launch providers operate exactly this way for their commercial customers. Intelsat doesn't buy launchers,they buy services. >>EXACTLY. Since we are making the government a real customer it will >>work just like Boeing. Now the govenrment is simply another buyer of >>launch services just like Intelsat (which McDonnell Douglas and GD >>already serve). >That ain't the way Boeing does it in Reality Allan. Look, McDonnell Douglas offered the government 20 HLV flights at a fixed price. If the government signed, they wouldn't pay a penny until the flights happened. If the flights didn't happen or the launcher didn't meet specs then the government doesn't pay. This is EXACTLY the way Boeing operates. >McDonnel Douglas is trying, but their cash position is not near as safe as >Boeing and I guarantee that the stockholders will not authorize the >expenditures of large amounts of company cash even if the government decides >to say they will guarantee the number of flights. And yet they made the offer. Perhaps the executives at McDac know more than you about finance and what the stockholders will go for. >BUT there ain't no way on God's green earth that >any of these guys would go for a contract that says "no deliver no pay" >without a hefty insurance policy. I'm sure that is true. The operative word is 'insurance'. Launch companies offer a wide range of services from 'we'll do our best but your on your own' to 'we're your one-stop shopping center for launches'. >Does this mean I can bid my Saturn Derived Vehicle (SDV) ? I would encourage you to. Although I doubt very much you can beat Zenith Star launcher prices. Allen -- +---------------------------------------------------------------------------+ | Allen W. Sherzer | "If they can put a man on the Moon, why can't they | | aws@iti.org | put a man on the Moon?" | +----------------------251 DAYS TO FIRST FLIGHT OF DCX----------------------+ ------------------------------ Date: 15 Aug 92 20:47:01 GMT From: Greg Moore Subject: ACRV/Soyuz P # of Passengers Newsgroups: sci.space In article <1992Aug14.152325.29323@iti.org> aws@iti.org (Allen W. Sherzer) writes: >In article strider@acm.rpi.edu (Greg Moore) writes: > >> Soyuz is great, Soyuz is God, Soyuz can carry ONE passenger. The >>other two occupants must be qualified as pilots. > >> The Shuttle is lousy, the shuttle is the eater of money, the shuttle >>can carry 5 passengers (or more). > >I would like to see a source for this. The Soviets tended to prefer automated >hardware and didn't let their crew do much if they could avoid it. There >shouldn't be too much trouble qualifying crews. > Source? Look at any Soyuz flight. If it were so easy, I'd think that the CIS would be willing to fly TWo paying passengers, rather than one. Also, looking at I believe the last 4 or so missions I recall 2 were done with manually docking. Finally, recall Mercury and the Capsule passengers? Oh, excuse me, the ASTRONAUTS who fought to have flight control. Trying to convince NASA and/or its astronauts to sit in a capsule while it flies without I think would be harder than convincing Congress of your ideas. >But I point out that if in fact you are correct, this is still a problem >for Shuttle. Soyuz WILL be the ACRV. Congress isn't going to fund anything >else. > This was my fault, the subject is misleading. As ACRV I do believe that Soyuz has its merits. As a method for exchanging crews, I have serious doubts. And you haven't made an argument yet. Just some simple handwaving about how easy it would be to qualify crews and that it would all be done automatically. Heck, the shuttle can fly automatically except for landing gear deployment (and that will change soon). Why bother flying with a Commander AND a pilot. Heck, dumpt them and you have 7 or more passengers. >Therefore if this is a problem, both approaches will sove it the same >way. > Not sure what you are saying here? >> With shuttle, you only need one shuttle flight. AND the shuttle can >>supply the station in the same flight. > >And if we have enough money that we don't mind wasing most of it, this >is just fine. > I've just demonstrated that your costs may be higher than you're admitting, and all you can do is say how much the shuttle can costs. You've gone from 2 Soyuz flights (3+1 or 2+2) to recrew the station to possibly as many as 4, doubling your cost of Soyuz. >> If the station EVER (and I doubt this for a LONG time) gets to >>8-person capability you will need 6 Soyuz flights to recrew. > >I'm assuming three although even with six we still save money. > >> An added cost comes up with these multiple flights. > >In ten years of operation Shuttle has not come down in price very much. >As to additional flights reducing cost, it won't happen since Shuttle if >flying at maximum rate now and CAN'T fly any more. > Non-Sequitor. I never argued that shuttle costs would come down. I argued that your non-hardware costs would go UP. Assuming you want to change the crew within a short period of time (i.e. in a week or so) you've got to launch 4 Soyuz's in the space of a week. HOW? >>Before you argue >>that costs would go DOWN as a result of a larger production line, keep in mind >>that you will need more launch pads, more ground support, etc. > >A government report (I think it was 'Launch Options for the Future') said >that there is plenty of facilities available to greatly increase the >rate of Atlas launches. HL Delta goes up from an unused launch complex and >all the costs you mention are included. > As you mention in a later post, there are ADDITIONAL facilities around, I would not say PLENTY! >>You can't >>simply double or triple the flight rate of any rocket without taking into >>account the cost of these factors. Therefore, I don't think your savings in >>production quantity would help, it would end up being eaten in launch support >>costs. > >The relevant government reports says larger launch rates can be sustained. >This will provide better utilization of ground facilities which will reduce >costs even more. > >> Finally, as my recent post concering the EOS system asks, why is the >>cost so low. > >1. It is a commercial procurement. The government isn't buying a launcher >but launch services. If the contractor doesn't deliver the payload, he >doesn't get paid. The govenrment will not be paying for the development >of HL Delta nor will it own the design. The contractor has every incentive >to keep costs in line since he looses $$ otherwise. > Sorry, my argument was not clear here. EOS should be handled the same way your are arguing for HL Delta etc. But, clearly the government does NOT want to work this way. One poster sent me a message explaing partly why. It's typical for contractors to underbid and ask for more money later. And I think this would happen with McDonnell Douglas. "Well, gee, we underbid and well, we are going to lose so much money that A) we can't build what you want and B) we're going to go out of business, taking hundreds of jobs with us." And what has the government done in the past? >2. The vehicles in question use mostly off-the-shelf parts with wide safety >margins. This works to reduce costs and increase reliability. > >> Your answer taht you've talked to teh engineers, ro that Boeing does >>it with aircraft all the time doesn't hold water with me. First: the >>companies in question have a tradition of giving lower figures, why change >>now? > >Because the rules are different. Before with cost plus contracts it was >to a companys advantage to add costs. With this effort where only services >are being purchased, that won't work. > >>Two: Boeing is operating in the real world with real customers who >>WON'T allow them to underbid and get away with it. > >EXACTLY. Since we are making the government a real customer it will >work just like Boeing. Now the govenrment is simply another buyer of >launch services just like Intelsat (which McDonnell Douglas and GD >already serve). > >Don't get hung up on HL Delta or Atlas. We aren't paying to develop >them. All we are doing is buying launch services from the lowest bidder >and it may not be either of those vehicles who get the contract. > Me hung up? Look around. :-) > Allen >-- >+---------------------------------------------------------------------------+ >| Allen W. Sherzer | "If they can put a man on the Moon, why can't they | >| aws@iti.org | put a man on the Moon?" | >+----------------------252 DAYS TO FIRST FLIGHT OF DCX----------------------+ -- <-------------------------------------------------------------------------> Greg d. Moore | Strider@acm.rpi.edu Green Mountain Software | "All that is gold does not glitter." Carpe Diem | ------------------------------ Date: Fri, 14 Aug 92 20:31:33 CDT From: evert@CPSnet2.cps.edu (Mike Evert) Subject: beanstalk in Nevada In Robert Forward's book "TIMEMASTER", he describes "rotovators". These would be rotating tethers in non equitorial orbits. The orbits would synchronized with the Earth's rotatation so that after a nice low number integer (say six) of orbits, the center of mass of the rotating tether system would be over the same spot on earth at the same altitude. The rotatation of the tethers would be going in a direction counter to the direction of the orbit. Rotation speed would also be synchronized so that each time the system returned over a chosen point on the surface, the business end of the tether would be dipping down into the the atmosphere with a tangental speed that is exactly opposite the orbital speed. It would appear from the ground that the end of the tether is descending and ascending nearly vertically. Because a "rotovator" need not be in an equitorial orbit, one of the chosen pickup and drop off points could be in Nevada. It seems to me that the synchronization would be tricky. The system has to satisfy many things. 1) Length of tether must extend from orbit to near ground. 2) Tangental speed must counter orbital speed 3) Ratio of orbital period to period of earths rotation (1 day) should be a manageable integer (like 6). 4) Ratio of tether rotational period to orbital period should also be a manageable integer (like 2). 5) The drop points of the tether should be within economical reach of markets via surface transportion as well in politically supportive areas. These points will have a rigid spacing around the globe so they must be chosen wisely. All the points above seem to be functions of the altitude and latitude of the orbit. Does anybody know what would be optimum? Mike ---- +----------------------------------+---------------------------------------+ | Mike Evert | "You are helplessly hypnotized. You | | Project Inform | will believe everything I tell you. | | Chicago Public Schools | This quoted message does not exist." | | evert@CPSnet2.cps.edu | | | 312-535-8675 | | +----------------------------------+---------------------------------------+ ------------------------------ Date: Sat, 15 Aug 92 21:09:01 CDT From: evert@CPSnet2.cps.edu (Mike Evert) Subject: beanstalk in Nevada In Robert Forward's book "TIMEMASTER", he describes "rotovators". These would be rotating tethers in circular non-equitorial orbits. The orbits would synchronized with the Earth's rotatation so that after a nice low number integer (say six) of orbits, the center of mass of the rotating tether system would be over the same spot on earth. The rotatation of the tethers would be going in a direction counter to the direction of the orbit. Rotation speed would also be synchronized so that each time the system returned over a chosen point on the surface, the business end of the tether would be dipping down into the atmosphere with a tangental speed that is exactly opposite the orbital speed. It would appear from the ground that the end of the tether is descending and ascending nearly vertically. Because a "rotovator" need not be in an equitorial orbit, one of the chosen pickup and drop off points could be in Nevada. Many drop points could be chosen at different lattitudes on both sides of equator. It seems to me that the synchronization would be tricky. The system has to satisfy many things. 1) Length of tether must extend from orbit to near ground. 2) Tangental speed of tether end must counter orbital speed. 3) Ratio of orbital period to period of earth's rotation (1 day) should be a manageable integer (like 6). 4) Ratio of tether rotational period to orbital period should also be a manageable integer (like 2). 5) The drop points of the tether should be within economical reach of markets via surface transportion as well as in politically supportive areas. These points will have a rigid spacing around the globe so they must be chosen wisely. 6) To have the multiple drop points at different lattitudes, the orbit should be circular. Satisfaction of all the points above seem to be a function of altitude and lattitude of the orbit. Does anybody know what would be optimum? It seems if the orbit were eliptical, there could be only a single drop point per orbit (probably at perigee). Again, the orbit could be synchronized with a low integer multiple of earth rotations. This would give a small set of predictable drop points, all at the same lattitude. Would this be easier to achieve? Mike -- +----------------------------------+---------------------------------------+ | Mike Evert | "You are helplessly hypnotized. You | | Project Inform | will believe everything I tell you. | | Chicago Public Schools | This quoted message does not exist." | | internet:evert@CPSnet2.cps.edu | | | delphi:LordMike@delphi.com | | +----------------------------------+---------------------------------------+ ------------------------------ Date: 15 Aug 92 18:41:11 GMT From: George Wm Turner Subject: Early Warning of missiles and meteors Newsgroups: sci.space >In article <6202@ucru2.ucr.edu>, judson@watnxt2.ucr.edu (Michael Judson) writes: > >A friend and I were having a discussion as to whether or not the early >warning system used in detecting missiles can actually detect meteors >that pass through the Earth's atmosphere. i know that they can track anything larger than a softball in close earth orbit (70's technology, today maybe they can track metallic tennis balls.) being able to detect something with radar is dependant upon what the object is made of. i would assume a iron meteor would be pretty shiney but even a stoney should have a pretty good radar cross section (compared to giant nerf ball.) the size of object one can detect with a radar is limited by the wavelength of the radar; you cannot see anything smaller than the wavelength you use for the radar. the earths atmosphere is opaque to some wavelengths. the major radio band opens up just under 1 cm and goes to almost 10 meters. there are a couple of narrow transparent bands around .9 mm 10 mm & 40 mm that could also be used. so there are several options to look for a 1 meter object. finding an object with a radar is also dependant upon search rate, i.e. how fast can you scan, how far can you see with your radar, and how fast is the object moving. today's over the horizon radars are phased array radars and their scan rates provide sub-second horizon to horizon scanning (no more revolving radar antenna). this leads to the fact that there are various kinds of radars, some pointing over the horizon, some searching line-of-sight, some looking from the ground up and some looking from the top down (i avoid saying space to ground because ground based over the horizon radars bounce their beams off the ionosphere back toward the ground). You have phased array radars which move their beams electronically and revolving radars which take time to spin. with a slow enough scan rate anything can slip through a design constraint in radars is how far can you see with the device. a radar works by sending out a pulse of radio waves then waiting for the return of an echo. the amount of time you wait for the return echo determines how far you can see with the radar. the distance being that time times the speed of light. these systems are built to look for object relatively close to the earth. they probably do not look much farther than geo-stationary orbit (22K miles). while on the descission of distance, of course you need enough power to get detectable return signal. the intensity drops off as the inverse square of the distance (double the distance and you have 1/4 the intensity) as for how long they had to see the object, that would depend on how fast the object was moving and what was the entry trajectory. if it came in slow from the north it would be more likely to be seen than if it came in fast from the south. our biggest fear was the soviets launching on us and we have tended to look for the threat from the north rather than from the south. (watch this change if brazil ever gets into medium range missles) these radar systems were developed during the cold war to search for objects on ellipitical or ballistic orbits. they weren't really set up to search for an object on inbound hyperbolic orbit. this means that they probably didn't see it coming but did they see it pass through their systems as it entered. it also depends upon wether they were looking. i would think so. soviet subs patrol off the east & west coasts. the cold war threat from these subs was that they could launch missles that would have short flight time to their targets. for a ballistic orbit this is on the order of 5 minutes to hit washington & 15 minutes to hit the mississippi. for sub-ballistic orbits these times drop to about 2-3 minutes & 7 minutes respectively. in looking for sub launched ballistic missles and discarding sonar detection (launching a ballistic from a sub is a very noisy process), you would look for the hot pulme of the missle`s exhast or detect with radar. orbiting satellites are used to search for the hot plumes but before that, you only had the radar system to search off the coast. surely the govt has had them. i think that was what the cobra dane radar was for but i don't really remember. there were the cobra dane & cobra ???? radars. these two radars were build in the mid 70s. i don't remember where they were or where they pointed but i'm thinking the pointed out off the coast versus pointing norhtward. >This was brought up because of the tidal waves that occurred in Florida >which meteorologists theorized may have been a meteor. My friend asked >why didn't early warning pcik it up, and I argued that early warning >could not pick it up. If it could, then why did the meteorologist have >to theorize about the meteor and instead not have solid proof from SAC? >-- >I was contemplating Socrates' immortal words: "I drank what?" >judson@watserv.ucr.edu they could detect it; if their systems were looking. the military is rather sensitive about how sensitive their equipment is. they wouldn't brag about seeing a 5 inch nick in the theorized meteor nor would they admit that a 1 meter chunk of iron plopped down in the good ole U.S. of A. & they missed it. (they were probably looking for plane loads of marijuana anyway.) nit-picks : SAC no longer exists. it too has gone the way of cold war. it has been replaced by some command that combined sac, tac & maybe mac. i don't remember the command's new name. the command that did the early warning stuff used to be called ADC {Air Defence Command} and they may have been absorbed into the Space Command. ADC searched the skys and did the airborne intercepts of threats; they protected the home front. SAC's job was to provide the offensive nuclear threat. george wm turner turner@bigbang.astro.indiana.edu if you want i.u.'s opinion, ask them, not me. ------------------------------ Date: 7 Aug 92 16:37:51 GMT From: Charles Frank Radley <3001crad@ucsbuxa.ucsb.edu> Subject: Energiya's role in Space Station assembly Newsgroups: sci.space RRegarding payload penalty for different inclination missions. Here are the numbers read off of a graph in the NASA Space Shuttle Payload Accommodations Handbook JSC 07700 Volume XIV Revision J of 1/27/88. The graph is a little small so these numbers might be off by a few per cent, these weights are in thousands of pounds:- Inclination Altitude: 100 nmi 220 nmi 300 nmi 28.45 deg 55 42 35 57 deg 40 30 23 Penalty:- 27 pc 29 pc 34 pc (per cent) The curve is a straight line between different altitudes, but I do not know whether you can interpolate linearly for different inclinations. I do not have data handy for any other launch vehicles right now, but I will dig around some more and post anything I might find later. These numbers do at least illustrate why NASA is using a 28.5 deg orbit for Space Station Freedom. They are constrained on the number of launches by Congress, and wish to orbit the maximum payload weight. ------------------------------ Date: Fri, 14 Aug 1992 17:12:39 GMT From: Pat Subject: Fermi Paradox vs. Prime Directive Newsgroups: sci.space In article <9208050516.AA16038@cmr.ncsl.nist.gov> roberts@CMR.NCSL.NIST.GOV (John Roberts) writes: > >Good point. I like your "failure of extrapolation" - that basically says >that we don't know enough to come up with a good explanation for the >Fermi Paradox. > How about this? Fermi's paradox in a nutshell. If planetary colonization is possible, why haven't we been? My conondrum. Who says this isn't so? ------------------------------ Date: 15 Aug 92 17:12:03 GMT From: Edward D Wright Subject: Nasa small business programs Newsgroups: sci.space I need some information. Does anyone know where I can get information on the various Nasa small business incentive programs? Even the names of the programs would help. Any information will be appreciated and I will summarize what I learn to the net As always Ed Wright ------------------------------ Date: 14 Aug 92 18:39:28 GMT From: Bruce Watson Subject: Persied Shower Newsgroups: sci.space In article <1992Aug13.175325.8504@isunix.cdx.mot.com| Mehrtens_T@msm.cdx.mot.com writes: |I was looking at the sky last evening, and I noticed that a bright star (like |the North star) was moving! It was "travelling" from north to south, approx. |75 degrees across the horizon, at 10:25 p.m. EST in Massachusettes, at a speed |faster than our intercontinental jumbo jets. It dimmed, and faded from view, |before it reached the center of the sky and never reappeared. I wonder if this |was the soviet spacestation? I remember, as a teenager, viewing our |spacestation (which travelled at a slower rate as viewed from the ground.) and |ours may have been brighter. No. Mir will return to evening skies for North America at the end of August. For a few days it will appear in the southwest and move to the northeast. For the two weeks after it will be seen low in the north moving from the west to the east. Then for a few more days it will appear out of the northwest and move to the southwest. It will be visible in the morning twilight and return to evenings in November. I can't tell if you are in eastern or western Massachusetts. If it is the Boston area, I couldn't find a good candidate for what you saw. -- Bruce Watson (wats@scicom) Tumbra, Zorkovick; Sparkula zoom krackadomando. ------------------------------ Date: 15 Aug 92 17:22:08 GMT From: kjenks@gothamcity.jsc.nasa.gov Subject: Solar System Journal Newsgroups: sci.space In article <1992Aug12.202853.15670@constellation.ecn.uoknor.edu> rwmurphr@uokmax.ecn.uoknor.edu (Robert W Murphree) writes: Early in the article, Murphree wrote: > [...] NASA's >real business is PR and aerospace company patronage, not science. Near the end of the article, he wrote: >GALILEO AT JUPITER IN 1995 > >Probe: The in situ probe of the atmostphere is the best possible >human participative experiencer for me. Just read me the isotopic, >elemental, molecular abundances with altitude profile. I'll make a >poster of it and put it on my wall. [Sarcasm dripping off every word.] Sheesh! We give you PR fluff, you want science. We give you science, you want PR fluff. There's no pleasing some people. That was a fun summary of interplanerary exploration. More! -- Ken Jenks, NASA/JSC/GM2, Space Shuttle Program Office kjenks@gothamcity.jsc.nasa.gov (713) 483-4368 "NASA turns dreams into realities and makes science fiction into fact" -- Daniel S. Goldin, NASA Administrator ------------------------------ Date: 15 Aug 92 15:28:34 GMT From: Paul Wilson Subject: Star Trek (anti-)realism Newsgroups: sci.space In article <1992Aug11.004823.5046@sugra.uucp> ken@sugra.uucp (Kenneth Ng) writes: > In article <1992Aug6.183507.19041@dartvax.dartmouth.edu:, Frederick.A.Ringwald@dartmouth.edu (Frederick A. Ringwald) writes: > : In article <1992Aug6.150955.15156@rsd0.rsd.dl.nec.com> > : buzz@rsd.dl.nec.com (Buzz McDermott) writes: > : > Personally, I like the fact that it took them about 10 minutes to accelerate > : > from earth to Sun (for their spring-board acceleration for time travel) > : > despite the fact that they were, at one point, going 'warp 8' and then 'off > : > the dial'. Isn't 'warp 8' supposed to be equivalent to something like 256 > : > times the speed of light? Gosh, the Sun must be further from earth than I > : > thought..... > : By the way, to have stars streaming by you, you'd have to be going > : several parsecs per second - and at that kind of speed, you could cross > : the Milky Way in eight hours (work it out yourself). Hmmm, I guess when > : they say "real space travel wouldn't look like that, it's just an easy > : video effect," they're right! > > My favorite in science fiction space travel like Star Trek and Star Wars is > the asteroid field. Never mind that even crowded fields they are still (in > reality) mostly space. True, but reality can make for some pretty lousy TV! -- Paul Wilson, P-and-S Ltd, P O Box 54, Macclesfield, SK10 1RD, UK [phone] +44 (0) 625 - 502224 [email] paul@pands.demon.co.uk ------------------------------ Date: 14 Aug 92 16:28:39 GMT From: Bob Niland Subject: Weird circle-like things on shuttle map Newsgroups: sci.space In sci.space, cortex@csli.stanford.edu (John Eisenberg) writes: > On the NASA channel, when they display the globe with the shuttle moving > around, there are all these cirlce-like things that have strange grooves. > They seem to all be around places that could track or serve as emergency > landing areas. What are they and why are they shaped as they are? Since you hadn't got any serious answers yet, let me take an educated guess... Each circle surrounds an earth ground station that can communicate directly with the shuttle (i.e., doesn't need to use TDRSS). The circumference of the circle represents the range of coverage, and may be adjusted on a flight-by-flight and orbital altitude/attitude basis. The notches represent no-signal areas due to terrestrial obstructions. If you reached into the circle and folded the notches up vertically, you would have a representation of what the horizon looks like from the center of that circle (the transceiver site) Since an emergency re-entry would take most of an orbit (if not more), there's not much point in depicting landing sites within range. The envelopes would not be circles and would not connect with the sites anyway, Regards, Hewlett-Packard Bob Niland Internet: rjn@FC.HP.COM 3404 East Harmony Road CompuServe: 71044,2124 Ft Collins CO 80525-9599 This article represents only the opinion[s] of its author, and is not an official or unofficial position of, or statement by, the Hewlett-Packard Company. The text is provided for informational purposes only. It is supplied without warranty of any kind. ------------------------------ Date: 15 Aug 92 17:07:34 GMT From: kjenks@gothamcity.jsc.nasa.gov Subject: Whither a Lunar Base (was: Energiya's role in Space Station assem) Newsgroups: sci.space,talk.politics.space In article <1992Aug11.205655.6840@csi.on.ca> richard@csi.on.ca (Richard Martin) writes: >When ARE we going to have a lunar base? Why don't we have one yet? We'll have a lunar base about six years after it becoms either politically profitable for a Government to fund one or about two years after it becomes economically profitable for a corporation to fund one. The only thing standing between us and a lunar base is money. Most of the engineering issues are readily soluble with a sufficient amount of money. As to why we don't have one yet, you'd have to ask Richard Nixon. He (and the U.S. Congress of the time) shut down the Apollo program and most of NASA's follow-on programs. According to Mike Collins, in 1969, Spiro Agnew proposed putting a man on Mars by the end of the century. And we all know that Dan Quayle is as pro-space as politicians come. Gore seems OK, too. Maybe the space program should pay more attention to the VP. (God knows, nobody else does.) Since the preponderance of motivations and problems in lunar base construction are political and financial, not scientific or engineering issues, let's take this discussion to talk.politics.space. -- Ken Jenks, NASA/JSC/GM2, Space Shuttle Program Office kjenks@gothamcity.jsc.nasa.gov (713) 483-4368 "Better. Faster. Cheaper." -- Daniel S. Goldin, NASA Administrator "That's no way to get to the stars!" -- me P.S. Richard, I note that you're posting from Canada. When is YOUR country going to start a lunar base? ------------------------------ End of Space Digest Volume 15 : Issue 115 ------------------------------