Date: Sat, 12 Dec 92 05:00:13 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V15 #532 To: Space Digest Readers Precedence: bulk Space Digest Sat, 12 Dec 92 Volume 15 : Issue 532 Today's Topics: absolutely, positively overnight (2 msgs) Asteroid Toutatis Cassini Undergoes Intense Design Review (2 msgs) DC info (3 msgs) DC vs Shuttle capabilities (2 msgs) Goldin Speaks at JPL GRAVITY-NEUTRALIZING AIR/SPACECRAFT Koptev's visit to McD (was: DC info) Saturn history Spacehab on DC stationary orbits over the poles what the little bird told Henry 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: Thu, 10 Dec 1992 17:28:52 GMT From: Henry Spencer Subject: absolutely, positively overnight Newsgroups: sci.space In article jbh55289@uxa.cso.uiuc.edu (Josh 'K' Hopkins) writes: >I'm no expert on jet lag. It just seems like going from breakfast to a late >dinner in the time it takes to skim a good magazine would have to throw your >system off. Since jet lag is way off the subject... Actually, not entirely off the subject. The problem in jet lag is the timezone change from origin to destination. How long it takes to get there is, to a first approximation, irrelevant. Although the airlines often make some attempt to smooth the transition, you can think of the situation as staying on origin time until you step off the plane, at which point you suddenly have to shift to destination time. However, on closer examination, trip time is relevant... because a long fatiguing trip can only make the problem worse. The shorter the better. >... On the subject of expense, the Concorde seems a >good example. It's never been profitable enough to make anyone else want to >buy one and it's at least 1.5 orders of magnitude cheaper than I can see a DC >type vehicle being. So where's the motivation for passenger travel? (I assume we're talking about surface-to-surface travel, not surface-to-space, which is a very different market with a proven audience.) I don't see DC-1 as a surface-to-surface passenger vehicle to any great extent. Prices would be high enough that you'd get only the cost-is-no-object crowd: the really rich and the people whose time is really valuable. I suspect you could make money by buying a couple of DC-1s, going all out on luxury interiors, and running them on a charter basis. It doesn't seem a promising basis for regular scheduled service, though. On the other hand, note that the Concordes seldom have many empty seats. Their market niche may be limited, but they do make an operating profit. You might be able to run scheduled DC-1 service on one or two well-chosen routes. I'm sure that if certification were suitable and appropriate facilities were widespread, there'd be a few executive DC-1s bought. The Saudi royal family would surely buy one. And then there's Air Force One... -- "God willing... we shall return." | Henry Spencer @ U of Toronto Zoology -Gene Cernan, the Moon, Dec 1972 | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 10 Dec 92 12:01:11 From: Steinn Sigurdsson Subject: absolutely, positively overnight Newsgroups: sci.space In article henry@zoo.toronto.edu (Henry Spencer) writes: I'm sure that if certification were suitable and appropriate facilities were widespread, there'd be a few executive DC-1s bought. The Saudi royal family would surely buy one. And then there's Air Force One... I hate to raise this, but are there ICBM proliferation concerns over open marketing of DCs? After all, it should have O(100 ton) payload for IRBM ranges and multiton payload for ICBM ranges and it can be arranged to come down hypersonically with what 1200 ft targetting accuracy? | Steinn Sigurdsson |I saw two shooting stars last night | | Lick Observatory |I wished on them but they were only satellites | | steinly@lick.ucsc.edu |Is it wrong to wish on space hardware? | | "standard disclaimer" |I wish, I wish, I wish you'd care - B.B. 1983 | ------------------------------ Date: Thu, 10 Dec 1992 23:43:07 GMT From: Ron Baalke Subject: Asteroid Toutatis Newsgroups: sci.space,sci.astro From the "JPL Universe" December 4, 1992 Asteroid to make close Earth approach Dec. 8 One of the largest near-Earth objects, an asteroid named "Toutatis," will make a close Earth approach Dec. 8, said Dr. Donald Yeomans of JPL's Navigation Systems Section 314. The object, formally known as Asteroid 4179, will pass by at about 3.6 million kilometers (2.2 million miles from Earth), said Yeomans. The asteroid passes Earth less than one degree above Earth's orbital plane every four years, making it an excellent object for study, he said. Toutatis' orbit takes it almost to the distance of Jupiter's orbit before the sun's gravitational attraction pulls it back. It will also make close Earth approaches in 1996 and 2000, and in 2004 will come as close as about four lunar distances, or less than a million miles. The asteroid, at 3.5 kilometers (two miles) diameter, is one of the largest to cross the Earth's orbit on a regular basis. Yeomans said the ground-based viewing conditions for infrared optical and radar observations just before, during and well after the close Earth passage will be excellent and he notes that astronomers in many areas of the world will simultaneously study the body, using several different techniques. The approach of Toutatis this year and the one in 2004 represent the two closest Earth passages of any known asteroid for the next 30 years, said Yeomans, head of JPL'S Near Earth Object Center. Toutatis was discovered Jan. 4, 1989, by astronomer Christian Pollas at Caussols, France, and was named after a Gallic deity who was protector of the tribe. ### ___ _____ ___ /_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov | | | | __ \ /| | | | Jet Propulsion Lab | ___| | | | |__) |/ | | |__ M/S 525-3684 Telos | The 3 things that children /___| | | | ___/ | |/__ /| Pasadena, CA 91109 | find the most fascinating: |_____|/ |_|/ |_____|/ | space, dinosaurs and ghosts. ------------------------------ Date: Thu, 10 Dec 1992 23:39:23 GMT From: Ron Baalke Subject: Cassini Undergoes Intense Design Review Newsgroups: sci.space,sci.astro,alt.sci.planetary From the "JPL Universe" December 4, 1992 Milestones, project-wide review in sight for Cassini By Franklin O'Donnell JPL's Saturn-bound Cassini mission is in the midst of passing several major milestones, with a critical project-wide review planned next week and recent reviews of the spacecraft's Titan probe and science payload. The critical design review, which will take an exhaustive look at the mission and all major spacecraft systems, is scheduled Dec. 8 at the Pasadena Hilton and Dec. 9-11 in JPL's von Karman Auditorium. The mission's Huygens Titan probe, meanwhile, was the topic of a system design review Oct. 12-16 at the Cannes, France, facility of Aerospatiale, which is building the probe for the European Space Agency. And plans among scientists whose instruments will ride on Cassini solidified this fall when NASA formally confirmed the mission's science payload. "All of the project's elements are moving forward very briskly," said Cassini Project Manager Dick Spehalski. "The critical design review will be an important step in the process of designing and building the spacecraft." Next week's meetings will include a comprehensive review of the project --spanning how it responds to science objectives, as well as Cassini mission design, orbiter systems, probe and launch-vehicle interface. In addition to JPL staff members, the review will include presentations by Dr. Hamid Hassan, ESA project manager for the Huygens probe, and Dr. Romeo Pernice of the Italian space agency, which is contributing Cassini's high-gain antenna. JPL Cassini Project Scientist Dr. Dennis Matson noted that science teams were very pleased by NASA's recent confirmation of the Cassini orbiter's 12 experiments. Another six fly on ESA's Huygens probe. Although the science instruments were tentatively selected in 1990, they were then subject to scrutiny during an "accommodation phase" during which the cost, weight and power needs of each experiment were carefully eyed. Matson credited JPL organizations with delivering "excellent packages" on plans for science instruments that were among the most challenging to bring in on a tight budget. JPL's Office of Space Science and Instruments is building the visual and infrared mapping spectrometer (VIMS) and the Titan radar mapper, while the Observational Systems Division is fabricating Cassini's optical cameras.Matson said science teams are now turning their attention to the ground system "and more detailed work on how we will go about flying this spacecraft." As for the Huygens probe, the green light at the October meeting in France paved the way for work to proceed, leading up to hardware deliveries in 1996 and 1997, according to Herb Phillips, JPL's Huygens technical integration manager. In all, ESA will deliver three versions of the Huygens probe to the United States. The first, an engineering model to be used during Cassini integration in JPL's Spacecraft Assembly Facility, will arrive on-Lab in February 1996. A second copy of the probe, called the structural thermal pyro model, will be delivered at JPL in June 1996. This model will be used for environmental testing in the Space Simulator. The third copy of the probe -- the actual flight model -- will be delivered directly to Kennedy Space Center in May 1997 for integration with the spacecraft at the launch site. The Cassini orbiter will be built up in JPL's Spacecraft Assembly Facility between September 1995 and May 1996. It will then undergo tests through spring 1997, when it will be shipped to Florida to be prepared for its October 1997 launch. After flybys of Venus (twice), Earth and Jupiter as it loops around the sun to pick up energy, Cassini will arrive at Saturn in November 2004, beginning a four-year orbital tour of the ringed planet and its 18 moons. The Huygens probe will descend to the surface of Titan in June 2005. ### ___ _____ ___ /_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov | | | | __ \ /| | | | Jet Propulsion Lab | ___| | | | |__) |/ | | |__ M/S 525-3684 Telos | The 3 things that children /___| | | | ___/ | |/__ /| Pasadena, CA 91109 | find the most fascinating: |_____|/ |_|/ |_____|/ | space, dinosaurs and ghosts. ------------------------------ Date: Thu, 10 Dec 1992 17:40:01 GMT From: Steve Flanagan Subject: Cassini Undergoes Intense Design Review Newsgroups: sci.space,sci.astro,alt.sci.planetary I just want to point out a minor error in an otherwise informative post... > After flybys of Venus (twice), Earth and Jupiter as it loops >around the sun to pick up energy, Cassini will arrive at Saturn >in November 2004, beginning a four-year orbital tour of the >ringed planet and its 18 moons. The Huygens probe will descend to >the surface of Titan in June 2005. The November '04 arrival date would apply only if the Titan IV SRMU is not available at the time of launch. If we can launch on the SRMU, our arrival date is June 25, 2004. Steve Flanagan Cassini Mission Design Team stevef@awolf.jpl.nasa.gov Standard disclaimers apply, ------------------------------ Date: Thu, 10 Dec 1992 15:22:31 GMT From: Paul Dietz Subject: DC info Newsgroups: sci.space In article <1992Dec10.150355.21296@iti.org> aws@iti.org (Allen W. Sherzer) writes: > It is a separate engine which will be used for DC-Y if built. Some of the > RL-200 engines will have extendable nozzles and will be sustainer engines > for DCY and others will have non-extandable ones and will be used as > boosters. Except for the nozzles, they will be the same. Will all 8 engines be used for landing? If not, it may make sense (not in DC-Y, but in a subsequent generation of vehicles) to make the booster engines different; in particular, make them burn a hydrocarbon, not hydrogen. Fuels burned early in the flight should be dense rather than be optimized for high Isp, in order to increase thrust at liftoff, reduce fuel cost and to reduce the mass of the empty fuel tanks that must be lugged to orbit. Question about the RL-10: what intake pressure do its pumps require to avoid cavitation? Hudson emphasizes that reducing this pressure is important in designing an SSTO, as lower pressure tanks can be lighter. Paul F. Dietz dietz@cs.rochester.edu ------------------------------ Date: Thu, 10 Dec 1992 17:12:24 GMT From: Henry Spencer Subject: DC info Newsgroups: sci.space In article mike@starburst.umd.edu (Michael F. Santangelo) writes: > I'm real foggy from this description as to what the RL200 engine is >going to be. Is it a name for many RL10-A5's grouped together through >a common master nozzle of some form? Or is it a seperate engine system >used to augment the RL10-A5's on the latter DC systems during flight...? No, it's a new engine, with some RL10 design heritage, relying on bits and pieces that mostly have been tested already. Only DC-X (and the proposed DC-X' suborbital flyer) will use RL10s at all. It's an excellent engine, but a bit small for the full-scale DC-Y. -- "God willing... we shall return." | Henry Spencer @ U of Toronto Zoology -Gene Cernan, the Moon, Dec 1972 | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: Thu, 10 Dec 1992 17:54:43 GMT From: Henry Spencer Subject: DC info Newsgroups: sci.space In article roberts@cmr.ncsl.nist.gov (John Roberts) writes: >A static test sounds like a good idea. Would that include "full throttle"? I would assume so, but don't know for sure. >And do the operational plans for DC call for a system like that used >by the Russian spacecraft and the Saturn V, in which the spacecraft is >held down until thrust is sufficient for launch? I haven't seen details on the planned launch facilities for the "real" DCs. The hold-downs aren't absolutely necessary -- Thor did not use them and I don't think its descendant, Delta, does. The plus of hold-downs is that you get to find out whether the engines are running satisfactorily before committing to launch (especially on a craft which has all engines lit at takeoff). The minus is that you use precious fuel sitting there waiting for the hold-downs to be released, fuel that could be used to start the climb. For an SSTO, with limited fuel reserves and engine-out capability, I'd guess hold-downs are not worth the trouble. Better to handle troubles in flight than to waste fuel just in case. >-DC-X flies autonomously, not piloted from ground. Ground monitors system >-performance, initiates thrust termination > >Interesting approach. I suppose one motivation is to reduce the risk from >communications problems. Provided nothing goes wrong, automated piloting is clearly superior to human piloting -- it's more precise and less prone to error. Putting the automation on board rather than on the ground likewise makes sense. >A question - since it's an experimental design, will the DC-X have landing >gear sturdy enough to support its weight fully fueled, or will it have to >hover before landing on abort like the DC-1 is projected to do? Don't know for sure, but DC-X's fuel load is not that big -- max takeoff weight is only about double dry weight, unlike the real DCs where the disparity is a *lot* greater -- so I'd suspect its gear can hold it. >And if a >DC-X / DC-Y / DC-1 does for some reason land fully fueled, would the >spacecraft likely be destroyed, or would it just "crunch" the tail end >a little? If the latter, what would be the expected magnitude of the >repairs required? Again, not sure, but my guess would be that it would be a major repair job. Unless you were pretty lucky, most of the crunching would be done by the liquid hydrogen tank, which would probably have to be replaced, and that's half the vehicle. >So the DC-X, at least, will have a parachute... I don't believe the later DCs are planned to have them. DC-X can use the backup, because unlike the later ones it only has four engines. -- "God willing... we shall return." | Henry Spencer @ U of Toronto Zoology -Gene Cernan, the Moon, Dec 1972 | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: Thu, 10 Dec 1992 17:41:00 GMT From: Henry Spencer Subject: DC vs Shuttle capabilities Newsgroups: sci.space In article kentm@aix.rpi.edu (Michael V. Kent) writes: >>There appears to be no significant requirement to return large payloads. >>I can't think of anything larger than a Spacelab experiment rack that >>has to come down in one piece. > >I'd like to keep flying LDEF and EURECA (I know there are no plans for the >former, but is the structure still intact enough to refly, or did they >dissect it?). LDEF could be reflown. However, if you've got much cheaper transport for smaller objects, why bother? LDEF proper is a framework, a couple of shuttle grapple fixtures, and a combination nutation damper and passive stabilizer. The experiment trays are independent and self-contained. It wouldn't be difficult, time-consuming, or expensive to build a smaller version that could carry a dozen of the trays and would fit in a DC-1. Launching a few of those would be cheaper and better. That would also be closer to the original intent of LDEF. It wasn't supposed to be a one-shot. It was supposed to fly repeatedly, and to be a way of getting simple, cheap long-duration experiments into space with minimum hassle. The organizers had such high hopes for it... :-( >Here's a question that just popped into my head: Would a modified Spacehab >(note the "h") module fit in the cargo bay of the Delta Clipper? I think it's too fat. I could be wrong. In any case, it needs more infrastructure than the DC cargo bay provides -- for example, it has no life support of its own. -- "God willing... we shall return." | Henry Spencer @ U of Toronto Zoology -Gene Cernan, the Moon, Dec 1972 | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: Thu, 10 Dec 1992 19:37:03 GMT From: Gary Coffman Subject: DC vs Shuttle capabilities Newsgroups: sci.space In article henry@zoo.toronto.edu (Henry Spencer) writes: >None of these things is really a fundamental problem. > >Large payloads can go up in pieces for in-orbit assembly. In fact, if >you believe Fairchild's old Leasecraft study, this approach is superior, >because plugging things together in orbit is easier than making absolutely >sure they won't come unplugged during ascent. Remember that NASA was quite >happy, in the beginning, with a much smaller shuttle design. Yeah, but I also remember how much harder in space assembly has turned out to be than was originally expected. Hopefully they'll get better at it with experience. I also know how hard it is to assemble and check out complex systems down here on the ground in shirtsleeves. Anything much beyond simple mating of standard modules in space is probably stretching things too far. Insert tab A in slot B often turns out to be an exercise in frustration down here with resort to a bigger hammer being common. In space it's hard to swing a hammer effectively. :-) I appreciate the ability to test and kickstart if necessary payloads in orbit. That's why I support manned space. But intricate assembly probably still belongs on the ground. >DC-1's cargo bay will easily hold more crew than the shuttle can carry. >DC-1 is not going to replace Shuttle+Spacelab -- it's too small and its >stay time in orbit is too short -- but it could easily service a space >station that would. Hauling Spacelab up and down all the time is >incredibly wasteful. From the vague descriptions I've seen, the cargo bay would seem to lack elementary things like an air lock. Does that mean that passengers would ride up in a spacesuit and debark to a station? That plus the short on orbit time seems to mandate an operating space station as destination. Now I like space stations, but we don't have one yet. Nor are we likely to have a functional one in the short timeframe until DC-1 is projected to be operational. Doing vacuum transfers of biological materials would seem tricky as well. With the crew cabin in the middle, docking with a station would seem very difficult. That's an interesting question anyway. How is docking with Freedom supposed to be handled? Gary ------------------------------ Date: Thu, 10 Dec 1992 23:40:46 GMT From: Ron Baalke Subject: Goldin Speaks at JPL Newsgroups: sci.space,sci.astro,alt.sci.planetary From the "JPL Universe" December 4, 1992 `Take creative risks,' Goldin tells von Karman audience By Karre Marino In a quick stop-over at JPL Nov. 25, NASA Administrator Daniel Goldin told an overflow crowd of JPL personnel in von Karman Auditorium of his concerns about the future of NASA missions, precipitated in part by the looming possibility of budget cuts as a new administration takes power. But he challenged his audience to be bold: "Use new technology, take creative risks. Let's work on advanced concepts and look to the future: whether that means composite structures, (very lightweight) cameras or other nations' space programs. But we have to put technology money where it has its biggest impact. We need to do better in terms of commercializing space. We've done better with privatization." Goldin said that analysis of the budget for NASA's Office of Space Science & Applications since 1987 "is cause for alarm" -- that NASA may be on the wrong path. "We're spending more and more money on operations and less on cutting-edge technology to plant the seeds for the next generation," he said. The number of scientific spacecraft on the books is too few, and "we're using old technology to survive." Goldin said he is concerned that at the university level, professors and students do not have the dollars to fund their research. In fact, the question of federal monies was raised often throughout Goldin's speech: "As we compete for increasingly fewer dollars -- dollars we share with the National Institutes of Health, the Department of Housing and Urban Development, paying off the national debt -- NASA sees a smaller share of the federal pot. Some of those funds are being diverted from NASA. "Maybe we have to do a better job informing the public why we're vital, why our budget shouldn't be trimmed. We also have to tell Congress the whole truth." If a budget is set for $1.4 billion, he said, "we shouldn't come back and ask for another $70 million to cover software costs. Let's be up front and tell them exactly how much we need." The administrator also noted that President-elect Bill Clinton expects a windfall from government-funded technology, which must one day be used in the private sector to create more jobs. "We should be a test bed of technology, bringing in people from a variety of industries," he said. Goldin also discussed the possibility of working more closely with other nations, and other space programs. For example, "The Russians want to work with us." Their military program may be under the knife, he noted, "but they won't give up on their space program. This is a great opportunity to reach out on an international basis and have scientists (from different countries) work together. We could build more payloads here and fly them internationally, or fly payloads of other countries on our spacecraft." While NASA certainly has concerns about the future, the talk was not all gloom and doom. Goldin cited a number of programs that offer great hope: Mission to Planet Earth, Discovery, Space Station Freedom. And throughout his address, he frequently challenged JPL staffers to be creative, to submit their ideas to management, to ensure that NASA engenders a successful marriage of science and technology. "NASA and JPL can have great impact in lifting the spirits of the nation and the economy if we take risks and use cutting-edge technology. We can't be afraid to fail." And while JPL is meeting Goldin's challenges, the administrator will be busy making changes at the top: he plans to cut out the layers of red tape. "The paperwork has become a burden to scientists. We're going to fix that," he said. "We want to spend our money and energy on technology." ### ___ _____ ___ /_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov | | | | __ \ /| | | | Jet Propulsion Lab | ___| | | | |__) |/ | | |__ M/S 525-3684 Telos | The 3 things that children /___| | | | ___/ | |/__ /| Pasadena, CA 91109 | find the most fascinating: |_____|/ |_|/ |_____|/ | space, dinosaurs and ghosts. ------------------------------ Date: Thu, 10 Dec 1992 17:21:17 GMT From: Harald Hanche-Olsen Subject: GRAVITY-NEUTRALIZING AIR/SPACECRAFT Newsgroups: sci.math,sci.skeptic,sci.space (This is my third attempt at posting this. If our local NNTP host won't accept it this time, then so be it.) Why did you post to sci.math? > Gravity-NEUTRALIZING Air/Spacecraft > or ZERO/REDUCED-Gravity Chamber I think sci.skeptic might be more appropriate. Sci.skeptic readers, if you want to flatten this scurry over to sci.math and read the referenced article. I find it very entertaining. (What is this program that sci.skeptic folks use to compute a bogosity index (or whatever they call it))? > NASA should build an experimental spacecraft based on > U.S. Patent #3,626,605 Oh, what the heck -- I'll crosspost to sci.space too. Followup to sci.skeptic and sci.space, please... - Harald ------------------------------ Date: Thu, 10 Dec 1992 16:17:03 GMT From: "Allen W. Sherzer" Subject: Koptev's visit to McD (was: DC info) Newsgroups: sci.space In article <1992Dec10.152231.8279@cs.rochester.edu> dietz@cs.rochester.edu (Paul Dietz) writes: >Will all 8 engines be used for landing? Not as part of a normal landing. Although in an emergency the pilot may be looking hard for thrust wherever it can be gotten and to hell with ISP. >If not, it may make sense >(not in DC-Y, but in a subsequent generation of vehicles) to make the >booster engines different; in particular, make them burn a >hydrocarbon, not hydrogen. Funny you should mention that. The head of the Russian space program (Koptev) was in LA last week visiting McDonnell Douglas. He met with the head of the DC effort and they talked quite a bit about using the Russian RD-710 tripropellent engine. I think Bruce Dunn posted a good analysis of what could be built with that engine while still preserving the simplicity of the basic DC design. If the RD-710 is reliable enough it could be an excellent addition. BTW, when the briefing began, Koptev apparantly said that their studies indicated that SSTO couldn't be done with today't technology and that a reusable two stage vehicle was the way to go. After the briefing, he had done a 180 and said he believes that DCY could work. Allen -- +---------------------------------------------------------------------------+ | Allen W. Sherzer | "A great man is one who does nothing but leaves | | aws@iti.org | nothing undone" | +----------------------135 DAYS TO FIRST FLIGHT OF DCX----------------------+ ------------------------------ Date: Thu, 10 Dec 1992 17:31:00 GMT From: Henry Spencer Subject: Saturn history Newsgroups: sci.space In article prb@access.digex.com (Pat) writes: >>The first Saturn I flew on 27 Oct 1961, actually. > >So if the Saturn I was ready in 61, why didn't they use it for >Gemini? The test flights needed to make it ready (by von Braun's standards) covered the next several years. For one thing, the first few flights had no upper stage and were incapable of making orbit. -- "God willing... we shall return." | Henry Spencer @ U of Toronto Zoology -Gene Cernan, the Moon, Dec 1972 | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: Thu, 10 Dec 1992 17:29:23 GMT From: Josh 'K' Hopkins Subject: Spacehab on DC Newsgroups: sci.space kentm@aix.rpi.edu (Michael V. Kent) writes: >I'd like to keep flying LDEF and EURECA (I know there are no plans for the >former, but is the structure still intact enough to refly, or did they >dissect it?). I don't know off hand whether the structure itself is still reusable but I think it was originally designed to be. Besides, LDEF doesn't need a single active system so it ought to be trivial to build a new one if necessary. By the way, there's been some significant discussion of not flying EURECA again either. I don't know what the current situation is or whether it will change. >Here's a question that just popped into my head: Would a modified Spacehab >(note the "h") module fit in the cargo bay of the Delta Clipper? Dimension wise I believe it would (assuming DC-1 is built and follows projected dimensions). However, given the number of modifications you'd need for power and access and so on it may be more efficient to design a new one around the new launcher. However, since baseline proposals don't have Delta Clipper capable of orbiting for more that a few days it may not be useful to orbit a Space(l/h)ab type payload unless the launcher is redesigned too. -- Josh Hopkins jbh55289@uxa.cso.uiuc.edu Ho^3 !=L ------------------------------ Date: Thu, 10 Dec 1992 16:16:33 GMT From: "James B. Reed" Subject: stationary orbits over the poles Newsgroups: sci.space In article , 18084TM@msu.edu (Tom) writes: |> For the poles, forget about tethers. What you want is some kind of giant |> charged ring that you use sunlight to spin, creating a force from the |> magnetic field of the Earth that balances gravity... Yeah, but what happens next time the Earth's magnetic field reverses? :-) :-) ------------------------------ Date: Thu, 10 Dec 1992 19:20:26 GMT From: Gary Coffman Subject: what the little bird told Henry Newsgroups: sci.space In article henry@zoo.toronto.edu (Henry Spencer) writes: >In article pgf@srl03.cacs.usl.edu ("Phil G. Fraering") writes: >>BUT: if the main place where NASP materials seem to be being used is >>the heat shielding, and its re-entry temperature is lower than the >>shuttle's, wouldn't shuttle re-entry materials be just as useful? > >They'd probably work as well, but there is a durability problem. Having >to inspect every last damned tile is the last thing you want to do for a >vehicle that's supposed to have rapid turnaround. They're also heavy as I recall, something you don't need in a SSTO. I appreciated the summary you gave earlier, Henry. It looks like they have a better test program planned than what has been outlined here before. I still think their schedule is extremely optimistic and success oriented, but we'll see. Gary ------------------------------ End of Space Digest Volume 15 : Issue 532 ------------------------------