Return-path: X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson Received: from beak.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 ; Thu, 22 Nov 1990 01:32:36 -0500 (EST) Message-ID: Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Thu, 22 Nov 1990 01:31:48 -0500 (EST) Subject: SPACE Digest V12 #583 SPACE Digest Volume 12 : Issue 583 Today's Topics: Re: Photon Engine Re: The Space Plane X-30 = The Space Plane != X-29 Colored satellites Re: The great light bulb debate Zero-G Administrivia: Submissions to the SPACE Digest/sci.space should be mailed to space+@andrew.cmu.edu. Other mail, esp. [un]subscription notices, should be sent to space-request+@andrew.cmu.edu, or, if urgent, to tm2b+@andrew.cmu.edu ---------------------------------------------------------------------- Date: Wed, 21 Nov 90 17:02:44 EST From: John Roberts Disclaimer: Opinions expressed are those of the sender and do not reflect NIST policy or agreement. Subject: Re: Photon Engine >From: wuarchive!julius.cs.uiuc.edu!ux1.cso.uiuc.edu!news.cs.indiana.edu!maytag!watdragon!watyew!jdnicoll@decwrl.dec.com (Brian or James) >Subject: Re: Photon Engine > I may be misremembering, but I don't think the lasers are intended >for use in a 'pure' photon engine. Photon engines have to have very impressive >power supplies to generate large values of thrust (Power = C x Force, or >something? My mind is going...). My impression was that they use the land >based laser to evaporate reaction mass, with the benefits of not having to >carry the powerplant to orbit, and being able to achieve higher exhaust >velocities. > Granted, once you're in orbit, low thrust isn't a problem (if >you are patient), but surface to orbit launches work better if the >thrust is higher than the local gravity :) > James Nicoll Yes, F = power / c, where F is in Newtons, and c = ~3E8, so the systems we were describing would consume huge amounts of energy and yet have a thrust of only a few Newtons at best, and they would therefore be unsuitable for earth launch. The laser launcher system proposed by LLNL, etc. would work on an entirely different principle. In this case the laser is only used to transmit power from the power plant to the launch vehicle, so the weight of the power plant will not have to be lifted. As you describe, the laser heats a reaction mass, creating thrust. The reaction mass can be a block of ice, another solid such as polyethylene, or just the air under the craft (heated by contact with a metal plate, most useful for the first part of the trip, to save the solid reaction mass for later on). Theoretically, power consumption can be modest, acceleration gentle, and even some degree of steering possible. Perhaps Jordin Kare could describe the proposal in more detail (it's been a while). John Roberts roberts@cmr.ncsl.nist.gov ------------------------------ Date: 20 Nov 90 16:57:02 GMT From: swrinde!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!utzoo!henry@ucsd.edu (Henry Spencer) Subject: Re: The Space Plane In article <1990Nov19.185119.7576@ariel.unm.edu> john@ghostwheel.unm.edu (John Prentice) writes: >is NASP still intended to achieve orbit without rocket assist or have >they conceded defeat on that one? They've conceded defeat, last I heard, and NASP will use rockets for the final portion of a flight to orbit. -- "I don't *want* to be normal!" | Henry Spencer at U of Toronto Zoology "Not to worry." | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 20 Nov 90 09:38:12 GMT From: m2c!wpi.WPI.EDU!megazone@husc6.harvard.edu (MEGAZONE 23) Subject: X-30 = The Space Plane != X-29 In article <46985@eerie.acsu.Buffalo.EDU> v071pzp4@ubvmsd.cc.buffalo.edu writes: >I'm fairly certain NASP is a commercial venture. What I'm not sure of >is, is NASP the same as the X-29? Maybe the X-29 is the military vehicle >you're talking about. The NASP is a government venture. DARPA, NASA, USAF I believe. It is the X-30. The X-29 is the Foward Swept Wing research aircraft, of which there are two. The X-29 has been flying for some time now. It is a Grumman aircraft. ############################################################################### # "Calling Garland operator 7G," EVE Email megazone@wpi.wpi.edu # # MEGAZONE, aka DAYTONA, aka BRIAN BIKOWICZ Bitnet Use a gateway. Sorry. # ############################################################################### ------------------------------ Date: Tue, 20 Nov 90 17:28:56 EST From: John Roberts Disclaimer: Opinions expressed are those of the sender and do not reflect NIST policy or agreement. Subject: Colored satellites >From: unmvax!ariel.unm.edu!ghostwheel.unm.edu!john@ucbvax.Berkeley.EDU (John Prentice) >Subject: Re: STS 38 Observation Reports -- red? >Why do you suppose Lacrosse looks red? I assume they would not have >painted it (and if they did, would you paint it a light absorbing >color like red?). Are there solar panels that might reflect that >color? Interesting. I must admit, in many years of satellite tracking, >I don't recall ever having seen a color associated with a satellite, >so this is intriguing (I also have faith in Beresford's observations). >John Prentice >Dept of Physics >University of New Mexico I don't know whether there's any relation, but the TDRS satellite, launched from the Shuttle as a boring-looking cylinder, unfolds into a real work of art. They've got one on display up near the ceiling at the National Air and Space Museum, close to the V-2, the spare Skylab, and the HST engineering prototype. I presume the gold parts of TDRS are for thermal/meteorite protection, as on the Lunar Module. TDRS is basically a set of antennae. According to many reports, Lacrosse has a very large antenna. Larger/brighter objects are more likely to show color, because of the optical properties of the eye. (For instance, stars are much more colorful seen through a telescope.) John Roberts roberts@cmr.ncsl.nist.gov ------------------------------ Date: Wed, 21 Nov 90 14:42:57 -0900 From: "ACAD3A::FSRRC" <@BITNET.CC.CMU.EDU:FSRRC@ALASKA.BITNET> Sender: "ACAD3A::FSRRC" <@BITNET.CC.CMU.EDU:FSRRC@ALASKA.BITNET> ISECCo Update: Summer of '90: A supremely successful summer. November 21, 1990 We got a jump on our summer projects, staring work in early May, getting 2 greenhouses, 2 gardens and a significant amount of work done at the hanger site, not to mention getting the hole excavated for the biosphere structure. June, July and August saw us pushed for time due to outside projects, but we still managed to get raise chickens, expand the aquaculture (fish) system, and keep up with the garden. Our primary volunteer workers were Ray Collins, Terry Fike, and R. Scott Guse. The ISECCo Vice President, Joe Beckenbach, visited from California for a couple of weeks in June (as a part of winning the ISECCo Most Donations Award Joe got a 5 day sailing trip on Prince William Sound) and assisted. Other people who were instrumental in our summer success are Chandra Schaffer, Elisa Corning and Kelly Wilkinson. A few others, like Robert Hale and Pat Wilkinson, helped out as needed. All in all we totaled nearly 800 man-hours of labor over the summer. The Greenhouses While it may not appear that growing gardens is a function of a space group our gardens serve two purposes: they allow us to experiment with various means of growing things which will ultimately be used in the biosphere, and second they provide food for our volunteer workers. Our greenhouses are especially important for developing techniques for biosphere crops. The first greenhouse we build was primarily for hydroponics. It was a 8'x12' frame structure covered with fiberglas sheathing. Inside we built 4 trays, 3 of which held gravel and the 4th of which was soil. All of these trays were watered with hydroponics solution; the gravel with new solution and the soil with either old solution or water. We planted tomatoes, bell peppers, and brussels sprouts in the gravel and rutabaga, beets, radishes, cantaloupe and squash in the soil. We hadn't ever tried growing crops like this so we weren't sure what we were going to get. While we did get a fair crop it could have been improved; The tomatoes were touched a bit by a late frost, the brussels sprouts failed to produce at all (too much competition from the tomatoes they were planted next to?), the radishes went to seed and the cantaloupe didn't have a long enough growing season (this was expected). In spite of these troubles we harvested gallons of tomatoes, a bucket full of peppers, all the rutabaga we desired, beet greens, and several squash. The second greenhouse was an 18' x 40' structure, made from poles, string and visqueen (clear tarps) put up over a good patch of ground. We planted corn, squash, cantaloupe, beans potatoes and beets in it. In spite of overheating problems (it got into the 100's regularly during June) we got squash, corn, beans and beets. The cantaloupe (in both greenhouse) didn't have a long enough growing season. This was expected, but it did serve to show us the size of the plants and to give us an idea about soil requirements. Another notable failure was the potatoes in the visqueen greenhouse: we had hoped to have potatoes in early-mid July, but it was the end of the growing season before they could be harvested. This was most likely due to heat stress. The gardens Our gardens were both located in newly turned soil, and neither location (one being at my house and the other being at the hanger site) has good soil. In spite of this our crops did quite well. We are in the process of upgrading the soil with horse manure from local farms, chicken manure from our chickens and earthworm casts from our earthworm trays. Over the next few years we hope to improve the soil to the point where our crops will flourish. The garden at my house was 9 meters (30') x 12 m (40'), and is located on a south facing slope in a (primarily) silt soil. We had a garden here during the summer of '89 and plowed this area with a rented rototiller before we planted. Over the summer we expanded the area for the garden, and it is now 12 m. (40') x 20 m. (60'). We used the cat (tractor) to turn over the new ground, and pulled most of the sticks out of it. We expect it to be an easy job to plow it next spring, though we haven't improved it's soil yet so it may not produce very well next summer...indeed, we may leave it fallow for another year. The garden at the hanger site is of a similar size. It was formed from top soil dug from where the hanger is being built and dumped in a cleared part of the lot. The area is slightly south facing (5 degrees?), and is well protected from wind by the surrounding trees (which, unfortunately, tend to shade it during the early morning. The soil was somewhat better than that at my house, but is still nothing to brag about. This coming summer construction will probably prohibit planting this garden. Biosphere Construction The First CELLS, the name of our biosphere (a NASA acronym meaning "Closed Ecological Life Support System"), is being built on land 'lease/donated' by Marilyn Rowley. Included in the lease is the use of a mobile home, which was used to house our volunteer workers this summer. As a part of the deal we cleaned up the trailer, and got it to the point where it could be lived in by early May. Scott and Terry spent the entire summer in the trailer, and Robin and Chandra lived there occasionally. The excavation for the biosphere is right behind the mobile home, and most of the dirt from from the excavation was used to make a large parking pad in front. Construction this summer was 'limited' to digging the biosphere hole. This immense excavation took about a month to dig with the Catepillar Tractor, which was on loan from TANSTAAFL Inc. The hole is 12 m. (40') square and averages 8 m. (26') deep. We will dig another 1-1.5 m (3-5') before pouring the foundation, for we have just gotten through the silt (into gravel) in one corner of the hole and it is advisable to have the entire foundation in gravel. I have been attempting to get pictures showing the size and depth of the hole, with limited success. So far the best I've gotten have been aerial photos taken from a Super Cub (a 2 seater airplane). If you would care to see some of my attempts send a SASE to us at the address below and I'd be happy to send you a few black & white prints. The Aquaculture System We upgraded our fish system to a capacity near what will be in the biosphere. We have a 15 gallon aquarium, a 20 gallon aquarium, a 70 gallon bath tub, a 4'x6'x2' tank (360 gallons), and a 2'x4'x2' tank (120 gallons). These latter two aren't operational yet; we have been trouble with the liner outgassing (we think!) Our fish population started with 20 Tilapia a year ago and since then we've breed them twice; the first time we got around 80 and the second time around 60. We have lost 30-40 to various causes, so we now have a population of about 125. The largest of these is 8" long and weighs 1/4 pound, close to the optimum size for harvest. It appears that it will take a year to grow them to this size, so for a harvest of 2 every other day we would need a population of 365 fish, or about 3 times our current population. The Chickens While it has not yet been determined that we shall have chickens in the First CELSS we did want to experiment with them. Elisa Corning was instrumental in getting our poultry system established. She raised several varieties of birds in a cage behind her house. While it is too early to determine whether they will fit into the ecosystem or not, we have been gaining valuable experience in their habits and requirements. ON OTHER MATTERS: In June the Directors of ISECCo held a meeting, and at that meeting we voted to begin preliminary investigations on what is required to build a live model of a aerospace plane. The purpose of this model would be to have a device which would be capable of hypersonic velocities for critical component testing. Unfortunately this will be limited (at this point) to an intellectual exercise since all of our funds are being put into the First CELSS. This fall/winter we are in the process of upgrading the systems that we have developed thus far in an attempt to begin some preliminary cycling. We plan to tie the dehumidifiers to the fish and chickens; the fish and chickens to the hydroponics system (which is a part of the plant system) and the plant system will provide water (vapor) for the dehumidifiers. While none of these 'ties' will be closed, it will give us a working idea of how things will work. We will also gain experience in rates of nutrient flow, determine potential limits and discover the some of the problems (and cures?). Those of you who wish to know more can write me at FSRRC@ALASKA, or via the postal system at the address below. Please include a postal mailing address for all initial BITNET correspondence--we occasionally have letters whose computer return address fails for one reason or another. --Ray R. Collins:: President, ISECCo :::The International Space Exploration and Colonization Company::: :::P.O. Box 60885::Fairbanks::Alaska::99706::: Researching and Developing space oriented technology for the betterment of mankind. * * * * * * * * * * * * {end} ------------------------------ Date: Wed, 21 Nov 90 18:28:51 EST From: John Roberts Disclaimer: Opinions expressed are those of the sender and do not reflect NIST policy or agreement. Subject: Re: The great light bulb debate >From: zephyr.ens.tek.com!wrgate!mtdoom!dant@uunet.uu.net (Dan Tilque) >Subject: Re: The great light bulb debate >henry@zoo.toronto.edu (Henry Spencer) writes: >> >>Krypton is better than argon for the same reason that argon is better than >>vacuum: the denser gas slows the evaporation of the tungsten filament. >Obviously we need to take this to it's logical extension. It's time to >start recycling all that radon that everyone has in their houses. >And I want no namby-pamby whining about radon being radioactive. In a >lightbulb, that's not a bug, it's a feature. >Dan Tilque -- dant@mtdoom.WR.TEK.COM The mantles for gas lanterns are made with radioactive thorium oxide (presumably because of its mechanical properties at high temperatures). A reference book I have also states that it is included in trace quantities in the tungsten filaments of light bulbs (!). John Roberts roberts@cmr.ncsl.nist.gov ------------------------------ Date: Wed, 21 Nov 90 14:01:39 EST From: John Roberts Disclaimer: Opinions expressed are those of the sender and do not reflect NIST policy or agreement. Subject: Zero-G >From: sun-barr!newstop!exodus!norge.Eng.Sun.COM!jmck@apple.com (John McKernan) >Subject: Re: LNLL Inflatable Stations >aws@ITI.ORG ("Allen W. Sherzer") writes: >>An inflatable station could be made smaller for 0G however if they are >>to maintain artificial gravity, it is about as small as they can get. It's >>not clear which has more life cycle cost. Crew can be left on a spinning >>station for a year with no problems. >Soviet crews have stayed in orbit for over a year. They have demonstrated >that with advanced exercise machinery and lots of exercise it is possbile >to return to the Earth after a year in a 0g environment and completely >recover. "Recover" is the key word. Apparently nobody stays up there that long and remains what could objectively be called "healthy". As an ideal, a stay in space should be no more destructive to the human body than a comparable period on the earth. NASA (or a spokesman thereof whom I heard recently) has stated that it has no interest in chemical means to combat calcium loss - it prefers vigorous exercise, clean living, pure thoughts, ritual chants, and so on. Since the loss of bone calcium is essentially a chemical (or electrochemical) activity, I don't think they should be so quick to summarily dismiss the possibility of therapy involving chemical treatment. For that matter, a drug to block decalcification would be useful to many women on earth. John Roberts roberts@cmr.ncsl.nist.gov ------------------------------ End of SPACE Digest V12 #583 *******************