Date: Tue, 8 Sep 92 05:00:04 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V15 #175 To: Space Digest Readers Precedence: bulk Space Digest Tue, 8 Sep 92 Volume 15 : Issue 175 Today's Topics: Business Travel? Inflatable Space Stations - Why Not ? (2 msgs) Is NASA really planning to Terraform Mars? (3 msgs) Mars Observer Update - 09/04/92 Pluto Direct/ options (3 msgs) Relativity (2 msgs) Space markets (2 msgs) THANKS on shuttle traking program Venus orbiters 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: 8 Sep 92 02:13:28 GMT From: Byron Meadows Subject: Business Travel? Newsgroups: sci.space,rec.travel,soc.misc In article <5545@ssc-bee.ssc-vax.boeing.com> mattb@ssc-vax.boeing.com (Matt Baney) writes: > >I'm trying to get some information about how other companies treat >employees traveling on company business; so I have a couple >questions: > >Does the Frequent-Flyer mileage earned for company travel go to the >employee for his/her private use or is it retained by the company? Working for the gov't, we aren't suppose to use the FF mileage for ourselves but the system is not set up for the gov't to keep track of them or use them. > >What type of rental car do you get? > Cheapest possible ( ) > What ever the traveler desires ( ) > ?? > A mid-size is the standard rental. Usually a Ford Tempo(yuch!!) Sometimes if your lucky a Ford Probe or Mustang--you get the idea. >What is the policy for eating/living expenses when travelling?? > > ( ) Flat rate per diem and you can spend it however you like > How much per day $(_____) > > ( ) Actuals, company pays whatever amounts the employee acrues during > the business trip. receipts required yes( ) no( ), > daily maximum no( ) yes( )-how much $( ) > > Any restrictions on what is allowed/ paid for, etc?? NASA uses the per diem system which is broken down into 2 parts. We receive an allowance for lodging that is not to exceed a predetermined amount depending on the cost of living for the area--higher in places like NY or DC lower in less urban areas. Any cost above the maximum allowable comes out of your own pocket. If you stay in a hotel that is below the maximum you only receive that amount (you don't get to keep the rest). We also receive an allowance for Meal and Incidental Expenses (M&IE). This is also based on the cost of living for the area. However, whatever of this amount we don't spend we keep. >Are there any restrictions/policies about when trips should be >scheduled, ie. do you have to fly on your own time, or is travel >done on company time, or whenever is convienient?? Travel is scheduled based on when the work dictates we need to be there. Unfortunately, as we have complained before, if we travel on the weekend we are on our own time unless we report to work directly after arriving at our destination. > ---------------------------------------------- > > Just a few questions I was curious about?? Anyone out there have > any thoughts/comments > > > Hope this helps, Byron ------------------------------ Date: 7 Sep 92 13:51:47 GMT From: "Allen W. Sherzer" Subject: Inflatable Space Stations - Why Not ? Newsgroups: sci.space In article katzr@ucs.orst.edu (Russell Katz) writes: >Any of you experts out there have an answer as to why NASA doesn't use the >tanks as at least a temporary habitation? Check out the External Tank Study performed by Space Studies Institute a few years ago. They cover ET uses ranging from space stations to fuel recovery. 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?" | +----------------------228 DAYS TO FIRST FLIGHT OF DCX----------------------+ ------------------------------ Date: Thu, 3 Sep 1992 13:41:58 GMT From: "Michael K. Heney" Subject: Inflatable Space Stations - Why Not ? Newsgroups: sci.space In article katzr@ucs.orst.edu (Russell Katz) writes: >This is a bit related to the topic...I think. > >I have read in several sf stories about using the shuttle main tanks as >modules for space habitats...just having the shuttle carry the tank with it >into orbit. Some authors stated that it would not take any extra fuel(??) >to do so. > >Any of you experts out there have an answer as to why NASA doesn't use the >tanks as at least a temporary habitation? > I hardly qualify as an expert, but there are several very good reasons why NASA doesn't use the tanks. 1) They tend to come down pretty quickly. Empty, they're very low-density structures, which causes their orbits to decay fairly quickly. Note that the current direct-ascent trajectories used on shuttle launches has the orbiter climbing to apogee and the tank re-entering after MECO, with no burns to alter either's trajectory. The tank *is* set tumbling by venting LOX thru the top to produce a predictable cross-section and horrible drag characteristics, while the orbiter keeps a minimum drag attitude. 2) There's residual LH2 and LOX in the tanks - close to 5,000 lbs LH2, if I remember correctly. They don't run the tanks dry because the engines would "belch" as fuel flow became erratic the last few seconds - not healthy for the engines. Mission planners don't really want to carry that stuff around on the orbiter's belly any more than they have to - a valve-closing problem or just plain leakage could allow both LH2 and LOX to vent (the tank is built to be a throwaway; not space-certified orbital hardware), so they want to drop it as soon as possible. 3) The foam insulation has trapped gasses in it (it was foamed on in the atmosphere, after all), and there are concerns that it could "pop" like popcorn over time in vacuum, contributing a fair amount of debris in the same orbit as the orbiters like to use. There have been suggestions to wrap the tank in beta cloth or something similar once on orbit to contain this. 4) The level of on-orbit operations needed to convert an ET are non-trivial. There *is* an access "hatch" on the bottom of the LH2 tank - 3 feet in diameter and bolted on *very* securely. Martin Marietta (henceforth MM) has determined that a spacesuited astronaut *could* get through the hatch - it's *barely* big enough. Now, you need to somehow add on a *real* airlock, build internal structures, add power supplies, plumbing, windows, etc, all of which involves cutting and welding on orbit by astronauts on EVA. Yes, it sounds like fun (!), I'd go and do it in a minute, but it's more work and money than NASA can reasonably be expected to put out when it's easier and SAFER to build the stuff on the ground and boost it to orbit with minimal EVA required. MM has (at least as of 1989) an office which dealt with ET on-orbit applications. The US gov't apparently in 1988 or 1989 said that for a 5-year period, anyone who wanted an ET could have it *free* after launch provided they could assure controlled re-entry or maintenance of a stable orbit AND dealt with the insulation-popcorn concerns. I recall that it would require an extra 1800 lbs of OMS fuel for the OMS-2 burn to carry the ET all the way to LEO; this may fall within the "management reserve" allocated on a mission, but this reserve is for contingincies (e.g., the Intelsat rescue - damn near ran the tanks dry in the nose because of 3 instead of 1 rendezvous (rendezvouses?) (and very fuel-efficient flying at that). Bottom line - yeah, I'd like to see all that metal hauled up to orbit, too, even as just an orbital scrap yard. After all, we *will* at some point be able to use tons of metal in oribital apps sooner or later. There's been talk of a "beam builder" crunching the tanks into tiny pieces, melting them, and extruding truss members, for example. But it's not gonna happen this year, or next. -- Mike Heney | | Reach for the mheney@access.digex.com | * Will Work for Money * | Stars, eh? Kensington, MD (near DC) | | ------------------------------ Date: 7 Sep 92 23:55:32 GMT From: "Thomas H. Kunich" Subject: Is NASA really planning to Terraform Mars? Newsgroups: sci.space (I am reposting this at request) There have been suggestions of terraforming Mars, perhaps even Venus. There may even be other planets or satellites in the solar system that lend themselves to being improved upon by man. Well, I have a suggestion. We can talk of sending manned flights to Mars, but we do not have the technology yet, nor the budget for such a prolonged and possibly ineffective space flight. Maybe we haven't learned from recent attempts to mass produce science, but miracle breakthoughs simply don't happen on schedule if ever. So talk about terraforming with unknown technologies is premature to say the least. Yet we do have the capability of terraforming Mars or the very least modifying Mars to support life of some sort. The same could probably be said of Venus and other places. If the Gaia principle really exists, and I find the principle attractive, then we can let life do it's own work on these planets. It is a simple, possibly even elementary, matter to find various bacteria, algae, fungi, lichen etc. that can exist in the harsh environment of Mars. Or, for that matter, the upper reaches of the Venusian atmosphere. These life-forms are small, light and quite capable of being transported in rather massive quantities to these planets by presently possessed technology. Should there not be appropriate life forms, our present knowledge of biotechnology should lead us to be able to develop some in fairly short order. I suggest that we send a space vessel bearing our life substitutes to Mars and Venus. The cost is relatively miniscule. Thereon we can sprinkle the makings of man himself. Oh, maybe the results won't look like our ideas of life. If Gaia lives on Venus I am sure that she is a Venusian Gaia. We would find her, perhaps, a little hot blooded for our tastes. The Martian Gaia might be more to our liking but then again who is to say? So too for the Titan Gaia. Would the Gaia principle work? I, for one, think that it would. In any case the results would be a satisfying and informative experiment that would cost pennies along the lines of space travel these days. Of course it would be unethical to interfere with any life there may be already there. So considerable exploration would be necessary to give a moral basis for such a project. But consider this: Should man never be able to budge from this planet in earnest we will have had our moment of godhood and brought life to pass. And perhaps, after all, that is the true meaning of life. (This is a new posting on the subject) A couple of comments have come my way in regards to the Gaia principle. Maybe I ought to make myself lucid. My direct quote regarding Gaia was, "If the Gaia principle really exists, and I find the principle attractive, ~ ". I did not say, nor do I maintain, that there is anything of a supernatural nature about Gaia. Nor does it's original author to my knowledge, which is admittedly slight. Scientists can find no problem understanding nuclear physics, with it's myriad complex intertwining of actions and interactions. Physicists can talk for days, weeks or even months on end about how each step leads to the next which leads to the next in a steady flow of cause and effect that weaves a pattern of infinite complexity and beauty from simple original concepts. Geologists can trace the development of the earth's mantle over the millennia. The sedimentation and metamorphosis of one type of stone to the next. All with a precise line that natural laws predict with clarity at least in retrospect. Others can trace the beginnings of life on this planet, step by step, through eons of time. Showing how each evolution follows the previous and theorizing about the ecological changes that presented themselves to produce these changes. Cause and effect, cause and effect. Gaia, as I understand it, isn't a direct line that supposes that what we have now is what was meant to occur from the beginning. Gaia is the chain of events whereby life actually does change the world around it. After all, isn't it a little obscure to say that man is destroying his environment and then to imply that he is the only life form capable of doing so? I find it astonishing that intelligent people could _not_ find the Gaia principle interesting! No, as I say, I find the principle of Gaia attractive. I find that it is a theory that can be tested. I have suggested a test of that theory that can be run for a miniscule fraction of what terraforming projects of other types would cost. Something that requires very little in the way of new technology. And something that could result in the bringing of life to other lifeless worlds in this universe. And in the final analysis this may be the only way man can spread life off of this small planet. ------------------------------ Date: Tue, 8 Sep 1992 00:43:18 GMT From: Paul Dietz Subject: Is NASA really planning to Terraform Mars? Newsgroups: sci.space In article <+7qn_q-.tomk@netcom.com> tomk@netcom.com (Thomas H. Kunich) writes: >(I am reposting this at request) > >There have been suggestions of terraforming Mars, perhaps >even Venus. There may even be other planets or satellites >in the solar system that lend themselves to being improved >upon by man. ...> >It is a simple, possibly even elementary, matter to find >various bacteria, algae, fungi, lichen etc. that can exist >in the harsh environment of Mars. Or, for that matter, the >upper reaches of the Venusian atmosphere. These life-forms >are small, light and quite capable of being transported in >rather massive quantities to these planets by presently >possessed technology. Should there not be appropriate life >forms, our present knowledge of biotechnology should lead >us to be able to develop some in fairly short order. > >I suggest that we send a space vessel bearing our life >substitutes to Mars and Venus. The cost is relatively >miniscule. Thereon we can sprinkle the makings of man >himself. Pseudoscience about Gaia notwithstanding, this doesn't work. The surface of Mars is extremely dry. All terrestrial life requires liquid water to survive. Even bacterial spores are quickly rendered nonviable in extreme dryness: experiments that place spores in air of near-zero relative humidity at 25 C find that the DNA begins to degrade, and the spores become nonviable within weeks (for this reason, the bacteria that supposedly survived in the Surveyor on the moon were likely post-recovery contaminants). As for Venus: the clouds there are concentrated sulfuric acid. Should anything be able to survive there, which is doubtful, it could not terraform Venus into anything remotely habitable to humans, as the primary problem is how to get rid of the atmosphere. Converting it to oxygen and biomass doesn't work; there is just too much oxygen there. Paul F. Dietz dietz@cs.rochester.edu ------------------------------ Date: Tue, 8 Sep 1992 02:52:40 GMT From: David Knapp Subject: Is NASA really planning to Terraform Mars? Newsgroups: sci.space In article <1992Sep8.004318.23942@cs.rochester.edu> dietz@cs.rochester.edu (Paul Dietz) writes: >In article <+7qn_q-.tomk@netcom.com> tomk@netcom.com (Thomas H. Kunich) writes: >>(I am reposting this at request) >> >>There have been suggestions of terraforming Mars, perhaps >>even Venus. There may even be other planets or satellites >>in the solar system that lend themselves to being improved >>upon by man. >...> >>It is a simple, possibly even elementary, matter to find >>various bacteria, algae, fungi, lichen etc. that can exist >>in the harsh environment of Mars. Or, for that matter, the >>upper reaches of the Venusian atmosphere. Thomas, would you expound on which bacteria or fungi can exist in a hot sulfuric acid/sulfur dioxide environment? >> These life-forms >>are small, light and quite capable of being transported in >>rather massive quantities to these planets by presently >>possessed technology. Should there not be appropriate life >>forms, our present knowledge of biotechnology should lead >>us to be able to develop some in fairly short order. >> >>I suggest that we send a space vessel bearing our life >>substitutes to Mars and Venus. The cost is relatively >>miniscule. Thereon we can sprinkle the makings of man >>himself. Like his ashes, maybe. No, let's send Dan Quayle! He says that since there are canals on Mars, there's water and if there's water, then there's air and if there's air we can breathe. I suggest we send Dan Quayle to Mars so he can breathe there. >Pseudoscience about Gaia notwithstanding, this doesn't work. > >The surface of Mars is extremely dry. All terrestrial life requires >liquid water to survive. Even bacterial spores are quickly rendered >nonviable in extreme dryness: experiments that place spores in air of >near-zero relative humidity at 25 C find that the DNA begins to >degrade, and the spores become nonviable within weeks (for this >reason, the bacteria that supposedly survived in the Surveyor on the >moon were likely post-recovery contaminants). I think the most reasonable proposals involved life forms in the *regolith*, not at the surface. There is a great deal of evidence for abundant water in the regolith and there are places there where liquid water can exist. >As for Venus: the clouds there are concentrated sulfuric acid. Should >anything be able to survive there, which is doubtful, it could not >terraform Venus into anything remotely habitable to humans, as the >primary problem is how to get rid of the atmosphere. Converting it to >oxygen and biomass doesn't work; there is just too much oxygen there. > > Paul F. Dietz > dietz@cs.rochester.edu Really the most interesting aspect of terraforming either planet is the amusing speculation. -- David Knapp University of Colorado, Boulder Perpetual Student knapp@spot.colorado.edu ------------------------------ Date: Mon, 7 Sep 1992 19:00:52 GMT From: Steve Collins Subject: Mars Observer Update - 09/04/92 Newsgroups: sci.space,sci.astro Boy it will be nice when Mars Observer is in space where it's safe... steve collins MO-SCT ------------------------------ Date: 7 Sep 92 17:32:53 GMT From: Pat Subject: Pluto Direct/ options Newsgroups: sci.space I saw parts of the pluto direct flyby talk by staehle from JPL. they are talking of sending a 1-200 kg orbiter to pluto. Did they consider using energia? most of the charts I remember were using titan or delta class launchers? I was thinking an energia would allow a bigger bird or possibility of more thrust to slow down the encounter. Does anyone know if that's an idea, or do they want to hold costs down to $150 million? ------------------------------ Date: Tue, 8 Sep 1992 04:37:00 GMT From: "Horowitz, Irwin Kenneth" Subject: Pluto Direct/ options Newsgroups: sci.space In article <1992Sep7.173253.1837@access.digex.com>, prb@access.digex.com (Pat) writes... > > >I saw parts of the pluto direct flyby talk by staehle from JPL. >they are talking of sending a 1-200 kg orbiter to pluto. > >Did they consider using energia? most of the charts I remember >were using titan or delta class launchers? > >I was thinking an energia would allow a bigger bird or possibility of >more thrust to slow down the encounter. > >Does anyone know if that's an idea, or do they want to hold costs down >to $150 million? > I was also at Staehle's talk at the WSC and since I have some background on this mission, I will attempt to describe it. The plan is to send a pair of spacecraft to Pluto on a direct trajectory. The mass of each craft is currently 164kg. They are talking about launch on either a Atlas or a Proton (the Atlas would allow a slightly higher payload mass). The current launch date is 1998, with an 8 year flight time to Pluto. Each craft will be able to carry out 4 primary science experiments: Optical imaging using a CCD camera, UV spectroscopy, an IR payload and radio science using the main antenna. The mass allocation for the three instruments is only a few kgs. Power will be provided by an RTG. This mission is an example of the new "cheaper, faster, better" attitude that Goldin is trying to bring to NASA. The budget is only $400M for the entire mission, and they are real serious about sticking to that figure. Getting the craft off the ground in six years is much faster than other big projects that NASA has undertaken in recent years (JPL is learning a hard lesson from CRAF/Cassini). As for better, well that will have to wait until they get out to Pluto to determine :-). The primary drivers in the past were performance, schedule, cost. For this mission, these have been reversed, so that cost is the primary consideration, and they are going to overlook a lot of potentially interesting science in an attempt to avoid the pitfalls of many other projects, that just grew too big b/c everyone wanted a piece of the pie. In addition, Staehle is committed to bringing a large number of students into the project, and primarily those students will come from local SEDS chapters here in LA. (SEDS==Students for the Exploration and Development of Space). Indeed, if you had the chance to see the mockup of the flyby craft in the exhibition hall (in the main NASA area in front), that was built by one of the members of Caltech SEDS as his summer project. ------------------------------------------------------------------------------- Irwin Horowitz | Astronomy Department |"Whoever heard of a female astronomer?" California Institute of Technology |--Charlene Sinclair, "Dinosaurs" irwin@iago.caltech.edu | ih@deimos.caltech.edu | ------------------------------------------------------------------------------- ------------------------------ Date: 8 Sep 92 04:51:02 GMT From: Josh 'K' Hopkins Subject: Pluto Direct/ options Newsgroups: sci.space prb@access.digex.com (Pat) writes: >I saw parts of the pluto direct flyby talk by staehle from JPL. >they are talking of sending a 1-200 kg orbiter to pluto. Actually, they'd like to send two so that they can image both sides of the planet. >Did they consider using energia? most of the charts I remember >were using titan or delta class launchers? The two options are Titan IV and Proton (which is a Soviet rocket with a smaller fan club than Energia). They would prefer to use a Proton because of pricing, but they're unsure of the performance of Proton upper stages. >I was thinking an energia would allow a bigger bird or possibility of >more thrust to slow down the encounter. The problem is that a bigger probe is much more expensive, and you can't really slow down the encounter much without extending the trip time greatly. -- Josh Hopkins "If you are sitting in an exit row and you cannot read this card or cannot see well enough to follow these instructions, please tell a crew member." j-hopkins@uiuc.edu -United Airlines safety instructions ------------------------------ Date: 7 Sep 92 12:53:50 GMT From: David Meiklejohn Subject: Relativity Newsgroups: sci.space In article <14902@mindlink.bc.ca> Alan_Barclay@mindlink.bc.ca (Alan Barclay) writes: >#4300029 from John Roberts > >I always thought I had a good handle on the basics of relativity. Well, we all like to think we do, don't we? :-) >Can you have a look at this for me, and tell me what you think? OK, I'm just a humble engineer, but let's see... >A Thought experiment: > >Star A is four light years from star B. A spaceship leaves earth >and accelerates to .9 C and ceases acceleration when it passes >Star A. An observer inside the moving frame notes the length of >subjective time passing. When the ship passes star B, the observer >inside the frame has only experienced 1.95 subjective years. For him, >he traversed four light years in only 1.95 years. A subjective speed >of 2.05 C. [ mathematics deleted ] >However, if he were to use instruments to determine his velocity >relative to the frame of reference, his velocity would remain .9 C. > >The only flaw I can see in this is if my observer's velocity somehow >changes the timing of his observations of incidence with Star A or B. No, his time measured is 1.95 years, as you say. What you're missing is that there is no favoured frame of reference, given that he's not accelerating. Therefore, as far as our astronaut is concerned, he's stationary, and the universe is rushing by at 0.9 c. Now, when you move, the only relatavistic effect isn't time dilation. You gain mass, and your metrics contract in the direction of motion. This last effect means that the observer measures the distance between the stars as 2.17 ly. As far as he's concerned, he's taken 1.95 years to travel between two objects 2.17 ly apart, so he's measured his speed as 0.9 c. So, it all works out. >A recent SF book used relativistic mass to produce black holes. >i.e. accelerate a spaceship until it's massive enough to collapse >into a singularity. Something seems missing in this equation. >Could it happen? I don't see why not. To continue to accelerate, the spaceship needs energy. An increasing proportion of this energy is converted into mass, rather than velocity, as c is approached. The real question is, where did the energy come from? Assume that the spaceship used a perfect antimatter drive, so that all of the mass of it's fuel is converted into energy and is used for acceleration. In effect, your just turning mass into mass as c is approached. Nothing is gained, except maybe some compression, depending on how the ship is arranged. If that's the case, it would have to be close to gravitational collapse before it started. Maybe energy is fed from outside as it travels. Sounds dubious to me. >Not knowing the more complex math of relativity, I have no way of >proving it to myself. But I wonder if time dilation due to velocity >(and the gravitation itself?) would put the singularity at the end of >an asymptotic curve, like v=1.0C, completely unachievable. I'm hardly an expert on black holes, but you don't need infinite density to initiate collapse, which is what your v=c would imply. -- David Meiklejohn | Internet : davidme@qdpii.comp.qdpi.oz.au Computer Systems Officer, QDPI | Fax : +61 70 92 3593 Mareeba, Australia | Voice : +61 70 92 1555 ------------------------------ Date: Mon, 7 Sep 1992 11:15:49 -0400 From: Samuel John Kass Subject: Relativity Newsgroups: sci.space >>A recent SF book used relativistic mass to produce black holes. >>i.e. accelerate a spaceship until it's massive enough to collapse >>into a singularity. Something seems missing in this equation. >>Could it happen? >I don't see why not. To continue to accelerate, the spaceship needs energy. Could it? I'm no expert either, but I thought that to get collapse, parts of the object had to be pulling against each other. Since the ENTIRE spaceship is accelerating, from the frame of reference of the spaceship, wouldn't it be 'normal' mass? Of course, from the frame of reference of a 'stationary' observer, the spaceship will have sqashed itself so flat that it should have fused anyway. Since, by general relativity, there is no preferred frame of reference, why would the Earth, then, not collapse into a black hole, just because such a thing is possible. (ie. Compared to the frame of reference of something else, the Earth has enough mass to collapse.) For example, there may be an object in the universe travelling at such speeds that, to it, the Earth should have collapsed into a black hole. But we're not a black hole. (I don't think.) >>acceleration. In effect, your just turning mass into mass as c is approached. >>Nothing is gained, except maybe some compression, depending on how the ship >>is arranged. If that's the case, it would have to be close to gravitational >>collapse before it started. it _IS_ possible to accelerate things without having the mass on board. Could we create a "black hole factory" with a long enough linear accelerator? --Sam Kass ------------------------------ Date: 7 Sep 92 13:03:32 GMT From: Gary Coffman Subject: Space markets Newsgroups: sci.space In article <1992Sep4.165453.2505@techbook.com> szabo@techbook.com (Nick Szabo) writes: > >There is no need for tiny-market HLVs; commerce can share launchers with the >military and civilian space agencies. The civilian agencies should be >following the lead of military and commerce, instead of living in their >own world building space stations, then building HLVs to support them, >none of it relevent to the commercial market. It's not the charter of the civilian space agency to follow in anyone's wake, certainly not the commercial sector. The agency is supposed to do space R&D that no commercial entity will attempt because it's too risky or too costly. The agency is supposed to break new ground, not ride the coattails of the military or commerce. The current commercial market is irrelevant to the agency's mission. Gary ------------------------------ Date: 7 Sep 92 13:40:59 GMT From: Gary Coffman Subject: Space markets Newsgroups: sci.space In article <6SEP199221315394@judy.uh.edu> wingo%cspara.decnet@Fedex.Msfc.Nasa.Gov writes: > >Look at the troubles Iridium is having raising their capital for a commercial >venture and they have a great business plan with a high rate of return. The >prime problem they have is that it is new tech and no one has sufficient >intestinal fortitude to bankroll them, therefore they are spreading the risk >and lowering their own returns by going into partnerships with many companies. >This has delayed the program for at least two years. Iridium has tremendous problems, but lack of guts isn't one of them. The two biggest problems faced by the system are regulatory issues on a global scale, and what to do if the system actually attracts a large user base. As terrestrial cellular providers are discovering, the big problem is achieving *small* enough cells to prevent the user base from overloading the system. A small satellite can't carry a big enough array to shrink cell sizes as demand increases. Users will quickly abandon a system where they almost always get a busy. Yet without a large user base the system can't turn a profit. They can try to limit the user base by charging $100 a minute for service, but there are only so many drug lords in the third world, and they've installed their own terrestrial cellular service. Iridium can't serve 4/5 of the world's population. All it can be is a plaything of the very rich, and the very rich are intolerant of limits. Investors aren't stupid. They can count very well. Iridium isn't risky because it uses advanced technology, it's risky because it's technology isn't advanced enough to serve it's potential market. Many companies have failed because they were too successful in creating a market for their products while being unable to deliver on their marketing promises when the scale got too big. Iridium's main danger is not that it will fail, but that it will succeed too well. Gary ------------------------------ Date: 7 Sep 92 22:23:35 GMT From: Matthew Sheppard Subject: THANKS on shuttle traking program Newsgroups: sci.space Thanks for all the responses on the shuttle traking program. I found it at ames.arc.nasa.gov , and it was called stsorbit.arc. Thanks again. -- | Matthew Sheppard CLARKSON UNIVERSITY sheppamj@sun.soe.clarkson.edu | | I'd rather have a bottle in front of me than a frontal lobotomy.ANoN | | I don't want a pickle. DoD#477 TEP#477 RIDE FREE (8^]..etcetera.. | ------------------------------ Date: Sun, 6 Sep 1992 18:59:46 GMT From: Pat Subject: Venus orbiters Newsgroups: sci.space In article <1992Sep1.151711.23979@elroy.jpl.nasa.gov> baalke@kelvin.jpl.nasa.gov writes: >aerobraking next year for Cycle 5. Of course, this is assuming that Magellan >isn't turned off at the end of Cycle 4. Magellan is in Cycle 3 right now with >Cycle 4 due to start on September 14. Each cycle lasts 243 days, or one >Venusian day. > ___ _____ ___ Rumour has it that COngress and certain unnamed NASA Brass want to keep magellan alive for as long as possible. The DDTE for Magellan was $600 million (appx) so why not burn 60 million more to get better gravity data.. also word is that small light probes are hot for funding in the near future. cheap fast missions are being experimented with to avoid cost problems with heavy big birds. ------------------------------ End of Space Digest Volume 15 : Issue 175 ------------------------------