Return-path: X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson Received: from hogtown.andrew.cmu.edu via trymail for +dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl@andrew.cmu.edu (->+dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl) (->ota+space.digests) ID ; Sat, 20 Apr 91 02:01:15 -0400 (EDT) Message-ID: <4c3xYYa00WBwQaUk5y@andrew.cmu.edu> Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Sat, 20 Apr 91 02:01:09 -0400 (EDT) Subject: SPACE Digest V13 #431 SPACE Digest Volume 13 : Issue 431 Today's Topics: Transportation Tethers Re: Questions about pioneer/Voyager Re: Advancing Launch Technology Re: Laser launchers NASA Prediction Bulletins, Part 1 Administrivia: Submissions to the SPACE Digest/sci.space should be mailed to space+@andrew.cmu.edu. Other mail, esp. [un]subscription requests, should be sent to space-request+@andrew.cmu.edu, or, if urgent, to tm2b+@andrew.cmu.edu ---------------------------------------------------------------------- Date: 16 Apr 91 17:14:33 GMT From: unisoft!fai!sequent!crg5!szabo@ucbvax.Berkeley.EDU (Nick Szabo) Subject: Transportation Tethers In article heskett@titan.tsd.arlut.utexas.edu (Donald Heskett) writes: >Could you explain what you mean by "tethers"? (Sorry if it has been >hashed and re-hashed Unfortuneately, it has been neither hashed nor rehashed. So, in the hopes that it will be, here are some possible transportation tether configurations: * A "tether" is simply a cable or wire of material with high tensile strength used for structural or momentum transfer purposes. A LEO tether rotates, hooking a launched payload and accelerating it from suborbital to orbital trajectory, while decellerating a similar payload into the earth's atmosphere. This counterweight could be a dead satellite, a payload needing reentry, or a piece of captured asteroid or comet. This reduces the cost of the ground launcher by over 2/3, since we can now use something like the Starbird to merely poke our head above the atmosphere, rather than building large launchers to go all the way into orbit by themselves. * A tether can be used on an airplane to swing a payload carried by that airplane into a suborbital trajectory. The payload can then be swung into orbital trajectory by a LEO tether. This was proposed by Keith Henson. * Given a medium-sized comet or carbonaceous chondrite asteroid captured into GEO and a mature space manufacturing industry, a Kevlar "beanstalk" might be built from GEO all the way to the Earth's surface. The operational cost of this would not be much more than the energy cost of elevators riding up and down this structure (about $4/kg). * Tethers can be used in deep space for various OTV purposes, for example in getting materials between asteroids. Given two asteroids opposite directions from earth, LEO, and a tether at each, we can launch payloads between these three locations with a near zero energy cost. We need to arrange the orbital trajectories from the asteroid, and schedule the payloads, so that the incoming payload's cumulative effects on the LEO tether orbit balance out. With more sophisticated scheduling, we can also use the incoming mass to boost payloads such as mining equipment from LEO to the asteroid, also at near zero energy cost. The main research problems are creating high-tensile, low mass fibers beyond Kevlar for such structures, and learning how to manufacture them from space materials. I am sure there are other possibilities along these lines which I haven't heard of. Tethers, like gravity assist and aerobraking, are another good example of substituting brain power for rocket power -- letting the solar system do the work for us. -- Nick Szabo szabo@sequent.com "The biscuits and the syrup never come out even" -- Robert A. Heinlein The above opinions are my own and not related to those of any organization I may be affiliated with. ------------------------------ Date: 16 Apr 91 16:11:50 GMT From: unisoft!fai!sequent!crg5!szabo@ucbvax.Berkeley.EDU (Nick Szabo) Subject: Re: Questions about pioneer/Voyager In article <1991Apr14.180423.29686@kuhub.cc.ukans.edu> utagikar@kuhub.cc.ukans.edu writes: [Pioneer/Voyager to Jupiter etc. questions] >1) How was the collision with astroid belts avoided? Other than minimal micrometeorite protection, no precautions were taken. Space is _big_ and it turns out that even the millions of rocks in the asteroid belt are easy to miss. This wasn't clear when the first Pioneer went to Jupiter, though, so there was a lot of figurative breath-holding when it passed through the belt. Galileo will intentially steer towards the asteroids Gaspra and Ida on the way to Jupiter to get a closer look. Good idea -- asteroids are important for both space science and space development. >2) How were/are they powered? If with nuclear power; how come NASA >doesn't quote its sucess to the people demonstrating against nuclear >powered crafts? Plutonium radioisotope thermal generators (RTG's). There was little controversy about this until the Galileo launch in 1990, for which NASA was taken to court by the Christic Institute and Jeremy Rifkin, largely to gain publicity for the latter groups. The judge soon threw it out. I find it hard to believe that NASA did not point out the success of Pioneer and Voyager during that court battle. >3) People who must have watched "First Contact" the episode in >Star Trek The Next Gen might recollect the government making the >decision on whether to disclose the contact.. Now considering Earth >with many different countries/governments, who made the decisions on >revealing our presence and technological prowess? The decision to make contact was made by the folks who set up all the high-power TV stations. Seriously, there is no way to control who contacts whom on this end, at least. There are idealists who are sure that ETI will be benevolent and are eager to send out our signature to the cosmos. Others would try to arrange things so that we find out about them before they find out about us. Either way, SETI is not taken seriously enough by governments for this issue to be a significant concern. -- Nick Szabo szabo@sequent.com "The biscuits and the syrup never come out even" -- Robert A. Heinlein The above opinions are my own and not related to those of any organization I may be affiliated with. ------------------------------ Date: 19 Apr 91 13:01:36 GMT From: agate!bionet!uwm.edu!caen!ox.com!hela!aws@ucbvax.Berkeley.EDU (Allen W. Sherzer) Subject: Re: Advancing Launch Technology In article <21561@crg5.UUCP> szabo@crg5.UUCP (Nick Szabo) writes: >I am sorry it violates your wishes. Now sit down, get the data for >launch costs between 1957-1991, and fit the curve for yourself. Perhaps you could give us the figures you are using and the sources? Ever since you incorrectly claimed that Titan was more expensive per pound than Delta I have been wondering where you get your numbers. Allen -- +-----------------------------------------------------------------------------+ |Allen W. Sherzer | If you love something, let it go. If it doesn't come back | | aws@iti.org | to you, hunt it down and kill it. | +-----------------------------------------------------------------------------+ ------------------------------ Date: 19 Apr 91 17:28:27 GMT From: agate!bionet!uwm.edu!wuarchive!rex!rouge!dlbres10@ucbvax.Berkeley.EDU (Fraering Philip) Subject: Re: Laser launchers In article <2753@ke4zv.UUCP> gary@ke4zv.UUCP (Gary Coffman) writes: >I wasn't arguing that R&D engineering problems need to be solved so >much as I was arguing that fundamental physical laws prevent the system >from being a practical, efficient, alternative to rockets. We could >throw hundreds of billions into an R&D engineering program to develop >anti-gravity too, but fundamental physical laws would have to be broken >for it to pay off. At the power levels required to loft real payloads >into orbit, atmospheric blooming is an intractable physical problem. >Once the air is ionized into a plasma, the plasma is optically opaque >cutting off further power transfer. Talk to the guys who have actually >fired high power lasers, the laser fusion folks, and see what they >say about the absolute necessity of having a hard vacuum to fire the >beam through. Oh boy, here we go again. Nick, does that phrase "intractable physical problem" look familiar to you? Did everyone notice in his post how he said the only laser that could do it is the gas dynamic (and that the CO2 has intractable cooling problems?) and that the implosion fusion program experience seems to indicate that laser launching is impossible? Well, here I go: 1. The cooling problem of CO2 lasers is probrably not nearly as bad as is currently solved in the current generation of rocket engines, and a CO2 cooling system on the ground wouldn't have the weight penalties. For that matter, back when Robert Bussard was trying to build cheap and dirty fusion reactors, he had an 'intractable cooling problem' too. If I recall right, however, it was the only problem he really solved. 2. The beam intensities needed by the implosion people is probrably higher than what you would find in a laser propulsion system. I recall that the beam is focused in the propulsion chamber on several designs to an intensity where blooming takes place, and the beam is blocked, keeping the chamber walls from being illuminated by the laser's full force (uncertianty alert!) 3. There are several different ways of building a laser propulsion system. If it really needs to go to vacuum, let's put it in vacuum: You put the laser in orbit, and use it to accelerate the upper stages of a suitable launch vehicle to orbital velocity. All the lower stages have to do is put the payload and laser motor up to where the atmospheric blooming is no longer a problem, and the rest is left as an exercise for the reader. I know that sun-pumped lasers in orbit have been proposed. 4. And now the most important point: fnord fnord. So you see, building a laser launcher is easy, fun, and profitable. Send your investment money, preferably in large cash denominations, to... :-) :-) :-) :-) -- Phil Fraering dlbres10@pc.usl.edu "The Soviet Union has neither soviets nor unions." - Eric Hoffer in 1974. ------------------------------ Date: 20 Apr 91 00:42:52 GMT From: udecc.engr.udayton.edu!blackbird.afit.af.mil!tkelso@tut.cis.ohio-state.edu (TS Kelso) Subject: NASA Prediction Bulletins, Part 1 The most current orbital elements from the NASA Prediction Bulletins are carried on the Celestial BBS, (513) 427-0674, and are updated several times weekly. Documentation and tracking software are also available on this system. As a service to the satellite user community, the most current of these elements are uploaded weekly to sci.space. This week's elements are provided below. The Celestial BBS may be accessed 24 hours/day at 300, 1200, or 2400 baud using 8 data bits, 1 stop bit, no parity. - Current NASA Prediction Bulletins #837a - Alouette 1 1 00424U 62B-A 1 91102.16227732 .00000403 00000-0 47023-3 0 3971 2 00424 80.4702 351.3044 0021773 224.7920 135.1386 13.67508692423552 ATS 3 1 03029U 67111 A 91 99.79553794 -.00000076 00000-0 99999-4 0 5200 2 03029 13.5673 18.6770 0017280 228.8932 130.9740 1.00272933 85769 Cosmos 398 1 04966U 71 16 A 91108.46825889 .00125583 19526-4 61577-3 0 5704 2 04966 51.5029 163.0806 2053127 25.3519 343.5150 11.53567171626088 Starlette 1 07646U 75010 A 91 98.35919790 .00000036 00000-0 75551-4 0 2029 2 07646 49.8200 73.7602 0205614 86.2479 276.1896 13.82154507816603 LAGEOS 1 08820U 76039 A 91102.35471075 .00000005 00000-0 99999-4 0 2209 2 08820 109.8367 97.6155 0044262 174.8990 185.1807 6.38664302 93047 GOES 2 1 10061U 77048 A 91101.78169883 -.00000257 00000-0 99999-4 0 5806 2 10061 8.7702 60.1271 0003940 21.8864 338.1519 1.00254745 52001 IUE 1 10637U 78012 A 91 98.90692571 -.00000180 00000-0 79862-4 0 2248 2 10637 32.7698 114.0796 1408565 1.1900 359.2080 1.00287730 9433 GPS-0001 1 10684U 78020 A 91101.10802193 .00000004 00000-0 99999-4 0 6150 2 10684 63.8990 80.3210 0127367 200.4223 159.0745 2.00553485 81821 GPS-0002 1 10893U 78 47 A 91100.11242070 -.00000022 00000-0 99999-4 0 3375 2 10893 64.2312 321.2043 0172427 23.9267 336.9049 2.00533682 94622 GOES 3 1 10953U 78062 A 91106.09771458 .00000101 00000-0 99999-4 0 621 2 10953 7.6692 62.7145 0004509 98.4289 261.5901 1.00285530 113 SeaSat 1 1 10967U 78064 A 91102.30722896 .00002008 00000-0 72557-3 0 4903 2 10967 108.0153 217.8309 0003072 223.1321 136.9680 14.36462424669391 GPS-0003 1 11054U 78093 A 91 98.85784464 -.00000021 00000-0 99999-4 0 3628 2 11054 63.7466 317.3902 0064432 116.8109 243.8969 2.00572320 91614 Nimbus 7 1 11080U 78098 A 91 99.75409735 .00000223 00000-0 23130-3 0 7391 2 11080 99.1734 2.6496 0009330 15.0547 345.0882 13.83534068629041 GPS-0004 1 11141U 78112 A 91101.47731067 .00000004 00000-0 99999-4 0 1461 2 11141 63.8332 80.1746 0061474 311.4816 47.9903 2.00546280 90364 GPS-0005 1 11690U 80 11 A 91100.11889813 .00000005 00000-0 99999-4 0 1083 2 11690 64.3401 82.5110 0123254 203.0580 156.4258 2.00552430 96196 GPS-0006 1 11783U 80 32 A 91 95.92533111 -.00000021 00000-0 99999-4 0 4068 2 11783 63.5636 316.9772 0162889 59.3932 302.2320 2.00576960 80196 GOES 5 1 12472U 81049 A 91 98.04615071 .00000136 00000-0 99999-4 0 663 2 12472 4.2014 72.1400 0003117 282.6346 77.4892 1.00252445 35183 Cosmos 1383 1 13301U 82 66 A 91 94.01230107 .00000267 00000-0 30280-3 0 6939 2 13301 82.9292 87.6399 0029159 78.0258 282.4149 13.67901179437435 LandSat 4 1 13367U 82 72 A 91101.49171165 .00001277 00000-0 29286-3 0 7349 2 13367 98.1340 162.4737 0002403 318.4307 41.5649 14.57168420464744 IRAS 1 13777U 83 4 A 91 98.04024139 .00000354 00000-0 26878-3 0 9132 2 13777 99.0138 295.0951 0012066 296.1180 63.8750 13.98920624 88166 Cosmos 1447 1 13916U 83 21 A 91102.18198900 .00000234 00000-0 23571-3 0 7890 2 13916 82.9456 151.0215 0039715 27.4985 332.8244 13.74132163403735 TDRS 1 1 13969U 83 26 B 91102.09494060 .00000127 00000-0 99999-4 0 3029 2 13969 5.1952 63.1215 0003509 328.3069 31.6948 1.00276849 2345 GOES 6 1 14050U 83 41 A 91101.03196172 .00000113 00000-0 99999-4 0 3984 2 14050 2.9783 74.7008 0001160 303.1214 57.1540 1.00282225 1127 OSCAR 10 1 14129U 83 58 B 91 97.32732770 .00000024 00000-0 99999-4 0 6462 2 14129 25.8493 151.9623 6008503 231.4593 58.2833 2.05882614 30790 GPS-0008 1 14189U 83 72 A 91 98.84920780 .00000003 00000-0 99999-4 0 9079 2 14189 63.5206 78.5948 0143419 225.3179 133.5023 2.00568376 56699 LandSat 5 1 14780U 84 21 A 91108.66838580 .00000427 00000-0 99999-4 0 6212 2 14780 98.2380 169.8199 0005504 168.8677 191.2646 14.57108271379208 UoSat 2 1 14781U 84 21 B 91108.60790668 .00004729 00000-0 85566-3 0 9969 2 14781 97.9080 155.6266 0012633 7.3169 352.8348 14.66747077380719 GPS-0009 1 15039U 84 59 A 91 96.03099321 .00000002 00000-0 99999-4 0 1797 2 15039 63.2702 77.7993 0028346 227.0133 132.7493 2.00565525 49915 Cosmos 1574 1 15055U 84 62 A 91106.71270673 .00000318 00000-0 33011-3 0 439 2 15055 82.9614 198.5420 0026787 195.5239 164.5101 13.73444883341732 GPS-0010 1 15271U 84 97 A 91101.95929275 -.00000021 00000-0 99999-4 0 246 2 15271 63.0471 316.1858 0112634 332.4467 27.0237 2.00564691 47147 Cosmos 1602 1 15331U 84105 A 91101.99618395 .00006628 00000-0 86677-3 0 5235 2 15331 82.5354 83.6497 0024656 76.0288 284.3674 14.80115320352259 NOAA 9 1 15427U 84123 A 91102.28360107 .00000955 00000-0 53396-3 0 7252 2 15427 99.1729 114.2159 0014121 248.7678 111.1989 14.12944064326211 GPS-0011 1 16129U 85 93 A 91 99.18533417 .00000003 00000-0 99999-4 0 7387 2 16129 64.0418 78.9192 0122971 147.7498 213.0202 2.00564741 40296 Mir 1 16609U 91107.85243023 .00080629 00000-0 81916-3 0 3804 2 16609 51.6067 233.4307 0010040 120.4867 239.7062 15.64417562295695 SPOT 1 1 16613U 86 19 A 91102.74200439 .00001385 00000-0 66853-3 0 2860 2 16613 98.6955 177.8183 0002034 69.5548 290.5845 14.20015950106447 Cosmos 1766 1 16881U 86 55 A 91102.09729676 .00004628 00000-0 61353-3 0 3778 2 16881 82.5255 142.2634 0023067 91.2586 269.1663 14.79497609253317 EGP 1 16908U 86 61 A 91 97.19363411 -.00000043 00000-0 -30202-4 0 3443 2 16908 50.0083 72.1433 0011329 223.6359 136.3561 12.44393894211464 NOAA 10 1 16969U 86 73 A 91 97.93691543 .00001129 00000-0 50757-3 0 5672 2 16969 98.5720 123.9135 0014050 129.2742 230.9686 14.24039231236559 MOS-1 1 17527U 87 18 A 91108.71213158 -.00000022 00000-0 -33126-5 0 8213 2 17527 99.0731 181.8043 0003907 10.1253 350.0261 13.94872872211854 GOES 7 1 17561U 87 22 A 91 98.75349979 -.00000045 00000-0 99999-4 0 7547 2 17561 0.0537 120.5656 0007317 286.6767 312.8294 1.00272554 8533 Kvant-1 1 17845U 87 30 A 91108.68282024 .00073000 00000-0 73933-3 0 5718 2 17845 51.6057 229.2136 0009666 118.6038 241.5881 15.64543445230577 DMSP B5D2-3 1 18123U 87 53 A 91102.89041825 .00001345 00000-0 72014-3 0 8964 2 18123 98.8153 294.4855 0013557 250.2382 109.7330 14.14502568196769 RS-10/11 1 18129U 91107.90229248 .00000521 00000-0 56128-3 0 5860 2 18129 82.9219 103.4085 0011775 1.9123 358.2087 13.72176641191329 Meteor 2-16 1 18312U 87 68 A 91106.88724636 .00000366 00000-0 32139-3 0 6235 2 18312 82.5533 49.5731 0013275 113.0284 247.2280 13.83767496184988 Meteor 2-17 1 18820U 88 5 A 91106.46001087 .00000189 00000-0 15809-3 0 4712 2 18820 82.5405 109.3736 0015812 187.6611 172.4317 13.84469815162149 DMSP B5D2-4 1 18822U 88 6 A 91102.95451567 .00001455 00000-0 67610-3 0 8333 2 18822 98.6045 340.1762 0007581 118.1611 242.0338 14.21933682165416 Glonass 34 1 19163U 88 43 A 91101.59514302 .00000020 00000-0 99999-4 0 2257 2 19163 64.9161 149.1941 0007175 201.8186 158.2458 2.13102739 22504 Glonass 36 1 19165U 88 43 C 91101.65199750 .00000020 00000-0 99999-4 0 2162 2 19165 64.8912 149.1814 0005346 319.8173 40.2355 2.13102997 22504 AO-13 1 19216U 88 51 B 91 78.38609337 .00000215 00000-0 44351-3 0 2424 2 19216 56.8112 104.6916 7140389 249.8316 25.0884 2.09695125 21173 OKEAN 1 1 19274U 88 56 A 91102.22969024 .00005506 00000-0 74687-3 0 865 2 19274 82.5136 240.8774 0020219 224.0264 135.9793 14.78617279149087 Meteor 3-2 1 19336U 88 64 A 91101.92664892 .00000121 00000-0 29681-3 0 7199 2 19336 82.5444 66.0743 0016059 288.9946 70.9502 13.16919571130273 Glonass 39 1 19503U 88 85 C 91102.14100201 -.00000018 00000-0 99999-4 0 1428 2 19503 65.4541 28.5082 0004507 197.9840 162.0067 2.13103614 20009 NOAA 11 1 19531U 88 89 A 91 99.26633402 .00001228 00000-0 69016-3 0 4775 2 19531 99.0242 53.5690 0012222 164.8291 195.3252 14.12059942130744 TDRS 2 1 19548U 88 91 B 91 97.94047857 .00000114 00000-0 99999-4 0 2362 2 19548 0.8528 80.4427 0001776 287.8629 351.6825 1.00276298 7877 Glonass 40 1 19749U 89 1 A 91102.18244873 .00000020 00000-0 99999-4 0 9270 2 19749 64.8596 148.8338 0007247 274.0599 85.9462 2.13102027 17539 Glonass 41 1 19750U 89 1 B 91102.24053305 .00000020 00000-0 99999-4 0 9806 2 19750 64.8804 148.8565 0007357 256.7635 103.2498 2.13102416 17530 GPS BII-01 1 19802U 89 13 A 91 58.17527061 .00000017 00000-0 99999-4 0 2319 2 19802 55.0455 187.3559 0050904 163.2354 196.8890 2.00558153 14865 Akebono 1 19822U 89 16 A 91101.96661259 .00043357 00000-0 23984-2 0 9891 2 19822 75.0846 90.5502 4100135 28.4707 348.9686 7.26602355 21280 Meteor 2-18 1 19851U 89 18 A 91106.72821041 .00000464 00000-0 40683-3 0 4243 2 19851 82.5248 346.6084 0012671 233.9489 126.0499 13.84119466107553 MOP-1 1 19876U 89 20 B 91 83.49540771 .00000025 00000-0 99999-4 0 1840 2 19876 0.2910 50.4188 0001552 314.1531 355.4087 1.00273956 3471 TDRS 3 1 19883U 89 21 B 91104.55447587 -.00000237 00000-0 99999-4 0 2376 2 19883 0.8772 77.6129 0041876 329.3605 313.6292 1.00271603 77911 GPS BII-02 1 20061U 89 44 A 91 58.00437706 -.00000034 00000-0 99999-4 0 2332 2 20061 54.8640 5.4895 0089842 183.4176 176.5173 2.00566400 12602 Nadezhda 1 1 20103U 89 50 A 91106.84603771 .00000296 00000-0 30378-3 0 3176 2 20103 82.9586 61.1570 0036160 274.3790 85.3247 13.73678121 89403 GPS BII-03 1 20185U 89 64 A 91 57.34599602 .00000016 00000-0 99999-4 0 1766 2 20185 54.8906 188.1900 0021289 164.8064 195.2144 2.00568043 11161 GPS BII-04 1 20302U 89 85 A 91 41.91577973 -.00000024 00000-0 99999-4 0 1785 2 20302 54.4598 307.3315 0032510 329.9999 29.8633 2.00556091 9656 -- Dr TS Kelso Assistant Professor of Space Operations tkelso@blackbird.afit.af.mil Air Force Institute of Technology ------------------------------ End of SPACE Digest V13 #431 *******************