Date: Mon, 22 Feb 93 05:00:13 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V16 #211 To: Space Digest Readers Precedence: bulk Space Digest Mon, 22 Feb 93 Volume 16 : Issue 211 Today's Topics: "DOES AMERICA SAY YES TO JAPAN" extreme responses to Challenger transcript How many RPM's around his own axle can human take? Mars Rescue Mission, what if! (3 msgs) McElwaine disciplined! McElwaine disciplined! (somewhat long) NASP (was Re: Canadian SSF effort ?? ) Nobody cares about Fred? PEGASUS QUESTION Pressure fuel delivery, ideas regarding Reliable Source says Freedom Dead, Freedom II to be dev Reliable Source says Freedom Dead, Freedom II to be developed Rocketeer Sabatier Reactors. Spy Sats (Was: Are Landsat Satellites receivable?) SSTO/DC-X in the Media.. Titan or Bust! (Saturn Moon)... 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: Sat, 20 Feb 1993 23:00:03 GMT From: Josh Hopkins Subject: "DOES AMERICA SAY YES TO JAPAN" Newsgroups: sci.space ar12@quads.uchicago.edu (Andre Robotewskyj) writes: >Hello, > Over the past few months, a paper entitled, "Does America Say Yes >To Japan?" (Louis Leclerc 1992) has been circulated over various computer >networks and BBS's. My first thought was that this was a little out of place. But then I thought about what's happened to station this week. I imagine, however, that the paper takes a rather different atitude then the last few days would suggest is accurate :-) -- Josh Hopkins jbh55289@uxa.cso.uiuc.edu You only live once. But if you live it right, once is enough. In memoria, WDH ------------------------------ Date: 11 Feb 93 14:12:46 GMT From: alexa@county.lmt.mn.org Subject: extreme responses to Challenger transcript Newsgroups: sci.space In article , lord@tradent.wimsey.com (Jason Cooper) wrote: > > > >My posting was not libelous, obscene, or otherwise criminal. Could someone please repost it? Thanks. _______________________________________________________________________ | Alex Alexander | The views expressed here are my own. | | LaserMaster R&D |---------------------------------------------| | Minneapolis, MN 55344 | "Your only validation is in living your | | alexa@county.lmt.mn.org | own life; vicarious existence is a | | (612) 943-9314 | fucking waste of time." -- Axl Rose | ----------------------------------------------------------------------- ------------------------------ Date: Sat, 20 Feb 1993 17:46:50 GMT From: jjj@mits.mdata.fi Subject: How many RPM's around his own axle can human take? Newsgroups: sci.space,sci.med I am not sure if this is the right group, but as space technology has also studied the limits of human, I'd guess there was somebody who knew: How many RPM's around his own axle can a human take? Let's take two cases: a human is sitting on a round table, under which is an electric motor, and then the same but standing on it? Some animals are known of being capable of taking very hard rpm's without suffering visible damage, but I would rather not to prefer being my own test subject in this matter! I need this information to designing an amusement park -type of thing, which will only be for "real fun" as opposed to the very lame apparates found in amusement parks. Of course I will finally test these on myself, but I needed practical guidelines along which I should be able to make safe tests. -- jjj@mits.mdata.fi | PGP 2.0 key available | PGP 2.0 avain saatavilla ------------------------------ Date: 20 Feb 1993 22:15:27 GMT From: "Kevin W. Plaxco" Subject: Mars Rescue Mission, what if! Newsgroups: sci.space In article <1993Feb20.191233.6482@ucsu.Colorado.EDU> fcrary@ucsu.Colorado.EDU (Frank Crary) writes: >That really depends on the nature of the problem. There is a paper >on rapidly sending small (under 10kg) packages to Mars within one >month. Yowzers. One month? 10Kg? Do tell! -Kevin ------------------------------ Date: Sat, 20 Feb 1993 19:12:33 GMT From: Frank Crary Subject: Mars Rescue Mission, what if! Newsgroups: sci.space In article <1993Feb18.030434.1@acad3.alaska.edu> nsmca@acad3.alaska.edu writes: >Wierd question? What is the mission to Mars fails, and the astronauts are >stranded, maybe not int he end, but early on. What steps would be done if >anything to rescue them?? That really depends on the nature of the problem. There is a paper on rapidly sending small (under 10kg) packages to Mars within one month. So it's very possible to send a stranded astronaut the three vital parts he needs to fix his rocket. However, if you mean "stranded" as in (say) "all the fuel in his rocket leaked out" (i.e. where a rescue would require tens of tonnes of new rocket/life support module/whatever...) There isn't alot that could be done. >Scenario if early in the mission, mabe a fly by resupply mission (space drop >versus air drop?). For heavy payloads (i.e. where you can't use as much fuel as you like) the orbital mechanics prevent any sort of rapid rescue. It is only possible to send things from Earth to Mars once every two years, and the transfer takes about nine months. So, once launched, an astronaut couldn't expect anything (major) from Earth for almost three years. Of course, three years isn't forever: It wouldn't cost a mission much to include extra life support supplies, making it possible to wait until a rescue could arrive (a typical mission would be about 500-days long anyway, because of the same requirements of orbital mechanics...) Also, missions can be designed to minimize these risks: While you can't send supplies _after_ the astronaut has left, you can send them before. In fact, the timing of transfer orbits and launch windows insures that pre-positioned supplies would have already reached the Martian surface before the astronaut left Earth: You can send vital equipment ahead and make sure it gets there safely before deciding to send the astronaut... >If later in the mission, namely on the way home. what is there available to >help them home.. Just about nothing: Any rescue would have to reach him _and_ match his velocity. That would require an essentially impossible amount of fuel. Frank Crary CU Boulder ------------------------------ Date: Sat, 20 Feb 1993 19:20:40 GMT From: Frank Crary Subject: Mars Rescue Mission, what if! Newsgroups: sci.space In article hrubin@pop.stat.purdue.edu (Herman Rubin) writes: >>Wierd question? What is the mission to Mars fails, and the astronauts are >>stranded, maybe not int he end, but early on. What steps would be done if >>anything to rescue them?? >Very little. The Scott expedition to the south pole died. Any frontier >is a dangerous place. However, the Shackelton expedition didn't, nor did Amendsen's: Risks can be minimized by carefull planning and having enough sense to give up and cut your losses, when serious problems come up... (More exactly, good judgement about when a solution can be improvised on the spot and when it can't.) >Would the astronauts have the mobility to get to the supplies? They wouldn't need much mobility: A resupply/resuce mission should be able to land within 250m of them (closer, if they have a radar transponder and meterological instruments so that the atmospheric conditions are well known...) Frank Crary CU Boulder ------------------------------ Date: 20 Feb 93 18:15:00 GMT From: Andrew Koenig Subject: McElwaine disciplined! Newsgroups: sci.skeptic,sci.space,sci.astro,sci.space.shuttle It always worries me when someone is stomped on because of what he says, even if what he says is unadulturated gibberish. Are we so thin-skinned that we can't just ignore stuff we don't want to see? Being suppressed doesn't make you Galileo, but there are an awful lot of crackpots out there who think it does. -- --Andrew Koenig ark@europa.att.com ------------------------------ Date: 20 Feb 93 23:15:37 GMT From: "Phil G. Fraering" Subject: McElwaine disciplined! (somewhat long) Newsgroups: sci.skeptic,sci.space,sci.astro,sci.space.shuttle cs000rjp@selway.umt.edu (Russell J. Pagenkopf) writes: >In article <24861@alice.att.com> ark@alice.UUCP () writes: >>It always worries me when someone is stomped on because of what he says, >>even if what he says is unadulturated gibberish. Are we so thin-skinned >>that we can't just ignore stuff we don't want to see? >* SOAPBOX ON * >I must agree with you Andrew. Just because *you* (newsgroups in >general) don't agree with what someone has to say doesn't mean you have the >right to CENSOR him/her. Yes, I agree that sometimes some of the posts can be ... Maybe it's about time a lot of these people learned about a newsreader called 'nn'. -- Phil Fraering |"...drag them, kicking and screaming, pgf@srl02.cacs.usl.edu|into the Century of the Fruitbat." - Terry Pratchett, _Reaper Man_ ------------------------------ Date: 20 Feb 1993 19:44:50 GMT From: CLAUDIO OLIVEIRA EGALON Subject: NASP (was Re: Canadian SSF effort ?? ) Newsgroups: sci.space > Aerospace Daily also reports that NASA research > on advanced subsonic and supersonic transport aircraft would > get a big increase under Clinton's budget plan, with $550 > million more programmed in fiscal years 1994-97, and another > $267 million scheduled for FY '98. What about NASP??? ------------------------------ Date: 20 Feb 93 18:44:05 GMT From: Pat Subject: Nobody cares about Fred? Newsgroups: sci.space In article hugh@huia.cosc.canterbury.ac.nz (Hugh Emberson) writes: |>>>>> On Thu, 18 Feb 1993 23:10:13 GMT, rbw3q@rayleigh.mech.Virginia.EDU (Brad Whitehurst) said: | |BW> In article <1993Feb18.193905.6405@iti.org> aws@iti.org (Allen W. Sherzer) writes: |>Some of the specific R&D projects I have worked on include: SeaFire |>Fire Control System (Navy), Integrated CNI Avionics (USAF), a Digital |>Map system I can't remember the name of (USAF), Pilot's Associate (DARPA/ |>USAF), Emergency Procedures Expert System (TI IR&D), Multi-Agent Planning |>(TI IR&D), Mission Planning Workstation (TI IR&D). |> |BW> Welll, Allen, I'm just a lowly mechanical engineer (hate those |BW> li'l electrons!!), but I would propose that there are some qualitative |BW> differences in forging a large, mechanical assembly out of steel, |BW> aluminum, and composites, compared to primarily software |BW> constructions. [...] | |Actually constructing large programs is not much different, if its |done properly. If its not done properly then the mess is a lot worse. | |There is a whole branch of computer science called "software |engineering" which aims to make the construction of large programs as |much like constructing a bridge as possible. > >Hugh I would argue, that it is easier to design large mechanical assemblies of steel, composites and aluminum and fabricate them to spec then to build large software programs. Engineering especially mechanical and civil are fields dating back to babylonian days. Most of the material interactions in a mechanical structure can be well understood and there are ASME/ ASTM/ ASCE/ PE standards regarding design and fabriacation. also finite element analysis gives a good understnading of real world behaviors prior to design. Then most structures have a solid testing program to verify performance. Computer systems suffer from poorly understood requirements, difficult planning and impossible test. most major systems involving software have had major software problems. the structure part tended to work better then the software part. ------------------------------ Date: Sat, 20 Feb 1993 17:55:15 GMT From: Bruce_Dunn@mindlink.bc.ca Subject: PEGASUS QUESTION Newsgroups: sci.space > Lawrence Curcio writes: > > Not to beat this to death, but regarding the marginal velocity supplied > by the B52: > > First, it was my impression that this was more than a couple of hundred > kph. Also, the altitude-for-velocity function is remarkably convex, once > one gets out of dense atmosphere. That is, there are increasing altitude > returns to marginal velocity, as velocity increases. Therefore, 600-1000 > kph more or less could make a difference in capability, IMHO. I don't think anyone is (seriously) suggesting "a couple of hundred kph", although one poster may have used this term dismissively. 200 kph is about 120 mph, which will be lower than the stall speed of any large plane used as a carrier. I suggested 200 m/s, which is 720 kph, or about 450 mph. This will vary however depending on the launch profile which is chosen. One approach is to fly as high as you can horizontally, maximizing speed, and dropping the rocket. The rocket must then do an aerodynamic or thrust vectored pullup to start climbing. An alternative is to dive the carrier vehicle, then pull the whole vehicle up into a steep climb before "lofting" the rocket. This gives a better launch angle, at the expense of velocity. Some proposals have included putting a rocket assist in the tail of the carrier vehicle to help the climb. Imagine a 747, whose engines normally generate something like 200,000 or 250,000 lbs thrust, augmented with an SSME with an atmospheric thrust of about 400,000 lbs thrust - now there's a high performance vehicle! -- Bruce Dunn Vancouver, Canada Bruce_Dunn@mindlink.bc.ca ------------------------------ Date: Sat, 20 Feb 1993 18:10:42 GMT From: Frank Crary Subject: Pressure fuel delivery, ideas regarding Newsgroups: sci.space In article henry@zoo.toronto.edu (Henry Spencer) writes: >>a. Transfer fuel from thin-walled main tank to theoretical smaller, thick-walled >> secondary tanks by *light* pressure-feeding. >>b. Close valve between main tank and secondary pressure tanks. >>c. Pressure-feed fuel from secondary pressure tanks... >This is a reciprocating pump of a slightly unusual type. Gas consumption >should not be significantly higher than for a straight pressure-fed system, >but it's not clear to me why it has much of an advantage over a reciprocating >pump powered by a turbine or something on that order. If the rocket is going to make several burns, the idea has some advantages: The fuel could be pumped slowly from the main tank to the pressurized tank, between burns. Since this wouldn't require much of a pumping rate, the pump could be substantially lighter than that of a normal rocket's pump. Frank Crary CU Boulder ------------------------------ Date: 20 Feb 93 22:43:39 GMT From: Josh Hopkins Subject: Reliable Source says Freedom Dead, Freedom II to be dev Newsgroups: sci.space C.O.EGALON@LARC.NASA.GOV (CLAUDIO OLIVEIRA EGALON) writes: >Do they already have a date for deployment of SSF II??? No. They don't even have any money. Just wait a few months and see what happens. -- Josh Hopkins jbh55289@uxa.cso.uiuc.edu You only live once. But if you live it right, once is enough. In memoria, WDH ------------------------------ Date: Sat, 20 Feb 1993 17:53:23 GMT From: tomas o munoz 283-4072 Subject: Reliable Source says Freedom Dead, Freedom II to be developed Newsgroups: sci.space In article <1m3pe3INNsng@access.digex.com>, prb@access.digex.com (Pat) writes: |> |> SO if we re-do SSF , how should we do it. |> |> Are trusses inherently more costly and problematic? |> certainly it allows larger growth. |> |> Should we look at something made from ETclusters along |> with Pre-built modules and inflatable zones? I feel that a total scrapping of the current work is very irresponsible. The SSF program is currently undergoing its CDR for flights MB1 - MB7 and UF1. At the end of this CDR around the end of summer beginning of fall, the design will be ~90% done. This is a huge milestone. Despite the bad press, a lot of good, sound work has already been done. |> Should we look at higher altitudes and and steeper inclination orbits? |> |> If we went to 48?? degrees, we could still launch from KSC |> yet also get Russian access for not a lot of cost? I concur here. The only things that would have to be worked out is the resupply/return capability and the logistics between US & CIS. |> I do like the idea of a 4.8 billion dollar go |> certainly that's a much more do-able and defendable figure. NASA can do two things to save a lot of money and still have a station with the current schedules and work: 1. Only build up to MTC [MB7 - first 8 flights] and delay/scrap everything after that. This would leave the station with a fully functional laboratory, a node, & ability to grow. 2. Only build the first two flights and use an EDO/LDO Shuttle as its laboratory. This configuration provides power for EDO/LDO orbiter stays, and provides prop to maintain altitude. Now, if the object of Clinton's redesign is to scrap the "Republican" station and put up a distinctly "Democrat" station, well then the cost issue is not about doing the right thing. -- ======================================================================== Tom Munoz | munoz@sweetpea.jsc.nasa.gov Thought for the day [plagiarized from someone else]: Engineers think equations are an approximation of reality. Physicists think reality is an approximation of the equations. Mathematicians never make the connection. ======================================================================== ------------------------------ Date: Sat, 20 Feb 1993 22:07:37 GMT From: Joe Cain Subject: Rocketeer Newsgroups: sci.space I wanted to illustrate something simple about rocketry to my planetary geology class (there is a chapter in our text "Exploring the Solar System: Space Travel" which includes a small section on Rocket propulsion with nothing informative except that each solid booster for the Shuttle has a thrust of 11,790,000 Newtons. I thought I might consider the olde Buck Rogers or Rocketeer back packs and let them compute how much fuel would have to be expended to keep a 100 kg payload hovering. e.g. 80 kg person and maybe 30 kg backpack. In order to do this I need to have a reasonable figure for what maybe a relative jet velocity might be. I have seen figures from 2000 to 5000 m/sec. Assuming say the 1950's idea of running something on alcohol (burned not ingested) what is a reasonable exhaust velocity? Alternately, I have seen a demo of an experimental flight unit, James Bond variety. What velocities are usual for such modern "man rated" devices? The expression I would be using would be a = v mdot/m where a is acceleration, v the exaust speed relative to the rocket, mdot the decrease of mass per time, and m the instantaneous mass being accelerated. Is this too simple? I assume we can show that to get more than an extra g over gravity you would burn all the fuel you can carry in a very few minutes. Now if you had a VERY bright flashlight... Joseph Cain cain@geomag.gly.fsu.edu cain@fsu.bitnet scri::cain (904) 644-4014 FAX (904) 644-4214 or -0098 ------------------------------ Date: 20 Feb 1993 14:11:01 -0500 From: Pat Subject: Sabatier Reactors. Newsgroups: sci.space In article <1993Feb18.202336.2373@ke4zv.uucp> gary@ke4zv.UUCP (Gary Coffman) writes: |In article <1m0kfnINNrfm@access.digex.com> prb@access.digex.com (Pat) writes: |>In article <1lrtf3INN82e@phantom.gatech.edu> matthew@phantom.gatech.edu (Matthew DeLuca) writes: |>|In article <1lrqqbINN63m@access.digex.com> prb@access.digex.com (Pat) writes: |>|>In article henry@zoo.toronto.edu (Henry Spencer) writes: |>| |>|>|In fact, you could |>|>|*probably* fuel an empty Centaur from residual propellants in the shuttle's |>|>|own external tank, and dispense with the fuel dump. [...] | |Yeah, except we'd use that fuel getting the ET into orbit, and we'd have |to design and install scavenging pumps in the ET to get to the fuel in |micro-G, etc. The ET isn't designed to supply fuel except under acceleration. Then we should be doing flight test programs to qualify and design pumps that could do exactly this. IF Shuttle is this great workshop then why cant we install some compressors and some refrigerators into it to recover residual propellants.? I have a workshop in my back yard, I don't have to spend billions of dollars sticking a 1 hp air compressor in there. The ET isn't designed to do lots of things but clever engineers have lots of plans to use them for other things. Come on gary. you dont think, the idea is impossible, so we should be doing it. we need to have the hardware base in place for futture projects. aOh and according to wingo, the shuttle doesn't use any extra propellant keeping the ET attached going up. Dennis, correct me if i am misquoting you. | |>|>If people are going to defend the shuttle as this marvelous |>|>workshop, then i suggest we see it do some real workshop |>|>type activities. Refueling satellites is a very reasonable |>|>mission, and it seems beyond the shuttles capacity. |>| |>|Read what he wrote. It's not that the Shuttle is incapable of doing it, it's |>|that NASA doesn't want to try it. Two different things entirely. |>| |>|(Do note, however, that "modest unknowns" is Spencer-speak for "we're |>|clueless"; it's not just a matter of hooking up a pump and pumping away. |>|We should learn to do it, though...we have to sooner or later.) |>|-- |>|Matthew DeLuca |> |>I agree. I don't see any reason why it couldn't be tried, |>but NASA is constitutionally unable to do such basic experiments. | |No, NASA is just terrified that if they did it Allen Sherzer would |scream in his best McElvane speak that the Evil NASA spent a BILLION |dollars to duplicate what any gas station in the SOVIET UNION could |do for pennies. And that it was all a PLOT to kill SSTO. | Red Herring artgument gary. and it stinks like a fish. Besides, fuel transfer technology especialy of Cryogenics is a must do for the DC-1 project. The DC-1-OTV and LLM both require in orbit fueling. IF Shuttle picked up the developement cost it's only help the DC-1's case. Besides Do you really mean to say that all those high government officials are afraid of little old alan? |>All those people who glorify NASA should push to see Shuttle |>used for such basic technology research studies. | |NASA is a government agency, so by definition it is already glorified, |however, they are doing basic research. The Drop Physics Module on |a recent flight was designed to find out how liquids behave in micro-G. That's an apples and oranges argument gary. playing with a couple cc's of water and glycerine on sticks is as far from pumping hundreds of pounds of LH2/LOX as breeding chickens and doing DNA recombinant experiments. We need to know how to move large quantities of fuel through hoses, valves, pumps, compressors and refrigerators in vacuum, in orbit. Many brute force assumptions (WE call them engineering assumptions) can be made to model the actual physics. while it may be elegant to know the behavior of a drop on a stick (Surface tension effects) it's maybe not relevant due to scaling factors in bathtub quantities. Engineering developement is oftentimes very different from theoretical physics studies. look at theoretical mechanics. it's only now we have the math to accurately describe solitons and catenaries. but bridges were built for centuries before then. IF we used your reasoning, it's only now we would build the brooklyn bridge. |That's applicable to any liquid transfer system that may be designed. |They also did an experiment to refuel a satellite's thrusters on one If i understand, they did a simulation using nitrogen gas. and it's nice, but they only did one or two experiments in 60 missions. Sherzer is right on when he says every! shuttle misison should have carreid a couple of suits and had the astronauts out there playing with hardware in vacuum. They should have been carying small tank systems up there and practiced setting up fueling lines and pumping and transferring liquid nitrogen, oxygen and hydrogen. And the EDO pallet is nice, but it's a passive system. what about pumps and refrigerators. ? |flight. The extended duration orbiter will have cryogenics stored on |a pallet in the bay. Etc. Remember that if NASA didn't have a zero |risk attitude, they'd just carry a fueled Centaur in the bay like they |originally planned. | |Gary And this is exactly the problem. If NASA was willing to take risks, they'd carry the centaur, they'd have an EVA program, THey'd be ou;there doing experiments on ET refueling and recycling. But no they don't because they are afraid. Afraid of risk, afraid of political pressure. they have their budget and they have their glorious manned space program and everyone is happy and cozy and nothing is changing. Gary, Do you have a problem with risk? your business is based on risk. people build things and then you test them. if the designers were so perfect, we wouldn't need testing shops like yours. pat ------------------------------ Date: Sat, 20 Feb 93 18:47:49 GMT From: Dean Adams Subject: Spy Sats (Was: Are Landsat Satellites receivable?) Newsgroups: sci.space martin@space.ualberta.ca (Martin Connors) writes: >henry@zoo.toronto.edu (Henry Spencer) writes: >> We could tell you, but then we'd have to kill you. :-) That phrase rings a bell.. >> Nobody who knows is going to be able to talk about it in public. The >> very *name* of the National Reconnaissance Office was classified until >> quite recently Which was a pretty ridiculous situation to say the least. >> The diffraction limit will make it impossible to do better than a few >> centimeters with visible-light optics that fit in current launcher >> payload shrouds. Yep... I have not seen many serious estimates beyond about the 6" range. >OK I will confess why I posted this. I saw Patriot Games (video) the >other days and found the portrayal of CIA operations using satellites >unrealistic to say the least. Actually, I thought they had most of the basic stuff down pretty well... although some was certainly exaggerated at least a bit. Advanced KH-11 birds are supposed to have "near real time" imaging capability, but that probably does not translate into the continuous view they portrayed. The BIGGEST error however was that their operation was at NIGHT, and these satellites are normally placed into sun-synchronous polar orbits to optimize their daylight coverage. I do not believe they have a significant nighttime imaging capability. >I heard through the grapevine that there was an instance of imaging >individual tiles on the Space Shuttle, which is likely possible from >a mountain site with guide star techniques to correct atmospheric effects. >But what would be routinely visible to a spy sat looking down? That report has been around a while... DoD's GROUND based tracking assets were certainly used and perhaps even one of their airborne platforms, but it may just be the press jumping to conclusions to think any satellites were involved. KH-11 orbits are not all that much higher than the shuttle, which would make an intercept pretty tight, and besides the optics are obviously optimized for resolving ground targets. ------------------------------ Date: 20 Feb 93 19:31:45 GMT From: CLAUDIO OLIVEIRA EGALON Subject: SSTO/DC-X in the Media.. Newsgroups: sci.space I have been reading that SDIO's funding will be cut and I was wondering is it going to affect DC-X??? C.O.EGALON@LARC.NASA.GOV ------------------------------ Date: Sat, 20 Feb 1993 18:26:58 GMT From: Frank Crary Subject: Titan or Bust! (Saturn Moon)... Newsgroups: sci.space In article <1993Feb20.021150.11662@ke4zv.uucp> gary@ke4zv.UUCP (Gary Coffman) writes: >>...I couldn't >>bare the thought of pinning my entire career on a single spacecraft >>that has (I can't emphasize this enough) *SEVEN* years in which >>to breakdown before I see any data. >The outer solar system is a *big* place. Nuclear rockets might make >it a little smaller, but anyone intending to work with outer planet >data just has to have more patience than you exhibit. And, unfortunately, >more stable funding than our space program exhibits. Even using chemical rockets, a transfer orbit to Saturn shouldn't take more than five years. (The outer solar system is big, but not quite that big.) I think Cassini is using another series of Earth and Venus flybys like Galileo (I have no idea why: I'd think a direct launch on a Titan IV would be possible...) If more advanced propulsion (nuclear thermal or nuclear electric) were available, I'd expect the transfer time to drop below three years (or the payload to increase dramatically, which ever you prefer...) Frank Crary CU Boulder ------------------------------ End of Space Digest Volume 16 : Issue 211 ------------------------------