dlbres10@pc.usl.edu (Fraering Philip) (11/06/90)
Ugh! here you go, I don't know the best way to prune this: In article <1990Nov3.194451.11017@engin.umich.edu> sheppard@caen.engin.umich.edu (Ken Sheppardson) writes: > aws@ITI.ORG ("Allen W. Sherzer") writes: > >In article <44053@eerie.acsu.Buffalo.EDU> you write: > > > >>On Freedom, everything is simply installed inside the modules before launch. > > > >At the Midwest Space Development Conference two weeks ago an engineer > >on Freedom implied that the modules had to be assembled in orbit. They > >are too big/heavy to fit on a single Shuttle flight. However, I didn't > >get a chance to ask him if my understanding was correct. > I believe a the current US Hab/Lab modules are too heavy to launch > fully outfitted using the current shuttle. From what I gather, the stripped modules run into problems with the shuttle senter-of-gravity limits. Phil
aws@ITI.ORG ("Allen W. Sherzer") (11/06/90)
In article <DLBRES10.90Nov5112553@pc.usl.edu>: >> I believe a the current US Hab/Lab modules are too heavy to launch >> fully outfitted using the current shuttle. >From what I gather, the stripped modules run into problems with >the shuttle senter-of-gravity limits. So how do they plan to launch them? BTW, anybody know when and where they are doing integration testing of Freedom? Allen -- +---------------------------------------------------------------------------+ |Allen W. Sherzer| I had a guaranteed military sale with ED-209. Renovation | | aws@iti.org | programs, spare parts for 25 years. Who cares if it | | | works or not? - Dick Jones, VP OCP Security Concepts |
crad@polari.UUCP (Charles Radley) (11/06/90)
+BTW, anybody know when and where they are doing integration testing
+of Freedom?
-
As far as I can tell, Freedom will never be completly integrated on
the ground. Some pretty big chunks of it will be integrated at a
new purpose built McDonnell Douglas facility adjacent to Johnson
Space Center, Houston.
That facility will be used for itnegrating the cargo for each
flight. Each flight's integrated cargo will be flown direct to
Kennedy where it will be installed into its shuttle.
As for when.....well, my hardware will be sent there in 1993.aws@ITI.ORG ("Allen W. Sherzer") (11/06/90)
In article <2667@polari.UUCP>: >As far as I can tell, Freedom will never be completly integrated on >the ground. You are going to take a first of its kind system the size of Freedom and do its first integration *AND* integration testing is space? And you think LLNL is risky? Doesn't that scare the hell out of you? (It would me). Allen -- +---------------------------------------------------------------------------+ |Allen W. Sherzer| I had a guaranteed military sale with ED-209. Renovation | | aws@iti.org | programs, spare parts for 25 years. Who cares if it | | | works or not? - Dick Jones, VP OCP Security Concepts |
otto@tukki.jyu.fi (Otto J. Makela) (11/08/90)
In article <9011041952.AA17871@iti.org> aws@ITI.ORG ("Allen W. Sherzer") writes:
[...]
After final testing, the entire Earth Station is deflated and packed
into a Delta or Titan derived HLV and launched. The crew follows on
a Delta, Atlas, or the Shuttle. They inflate the station and dock.
Question: what would the crew go up in, if not the Shuttle ? I was under
the impression that the Apollo capsules were the last crew transport
devices built before the Shuttle became available. Would some be
(re)built for this purpose only ? Sounds expensive...
--
/* * * Otto J. Makela <otto@jyu.fi> * * * * * * * * * * * * * * * * * * */
/* Phone: +358 41 613 847, BBS: +358 41 211 562 (CCITT, Bell 24/12/300) */
/* Mail: Kauppakatu 1 B 18, SF-40100 Jyvaskyla, Finland, EUROPE */
/* * * Computers Rule 01001111 01001011 * * * * * * * * * * * * * * * * */eempa@iceman.jcu.oz (M Parigi) (11/08/90)
What are the repairment proposals for damage due to space debris for the LLNL inflatable space station. Would the material tend to tear due to the pressure differential once a small rip was instigated (fail catastrophically, much like an ALOHA airliner did some time ago, ripping its top off) like most plastics, composites would; or would it tend to retain strength around the hole like (unfatigued) metal, for the proposed material of the inflatable station. What is the material being proposed? Marco Parigi. Electrical and Computer Engineering James Cook University N.Q. (They had nothing to do with it)
aws@ITI.ORG ("Allen W. Sherzer") (11/08/90)
In article <1221@iceman.jcu.oz> Marco Parigi writes: >What are the repairment proposals for damage due to space debris for the >LLNL inflatable space station. I don't know the details but provisions have been made. There is an outer bubble around each module pressurized to 2.5 PSI. If this is punctured, it will have no effect on the areas where people are. If it deflates, I assume they would go EVA and fix it. Space debris would need to go through the external shield, the outer kevlar envelope and the inner kevlar envelope before it could put people in danger. Also remember that since the station is inflatable the envelopes will absorb shock before puncturing, like a tire on your car. >Would the material tend to tear due to the >pressure differential once a small rip was instigated (fail catastrophically, >much like an ALOHA airliner did some time ago, ripping its top off) This is covered in the ILC report I quoted. Provisions are made to make sure that any rip does not become too large. Remember that this company has built large inflatable aerospace structures in the past. These are not new problems. Allen -- +---------------------------------------------------------------------------+ |Allen W. Sherzer| I had a guaranteed military sale with ED-209. Renovation | | aws@iti.org | programs, spare parts for 25 years. Who cares if it | | | works or not? - Dick Jones, VP OCP Security Concepts |
gary@ke4zv.UUCP (Gary Coffman) (11/09/90)
In article <9011081333.AA24041@iti.org> aws@ITI.ORG ("Allen W. Sherzer") writes: >Space debris would need to go through the external shield, the outer kevlar >envelope and the inner kevlar envelope before it could put people in danger. >Also remember that since the station is inflatable the envelopes will absorb >shock before puncturing, like a tire on your car. At the expected relative velocities of the blimp and space debris, the impact would vaporize the fabric not bounce off. Gary
3001crad@ucsbuxa.ucsb.edu (Charles Frank Radley) (11/13/90)
Since LLNL is a large lightweight structure it will be subject to high drag, compared with, say Freedom. This means more reboosting, more propellant (already a problem on Freedom), and higher engine duty cycles. Is there any way they can make it smaller ? There are practical problems with spinning a station. Need to despin every time EVA is needed, expensive on propellant/power. Structure must carry centrifugal loads, makes it heavier. Reboost thrusters must be gimballed, Freedom is gravity gradient stabilised, so reboost thrusters always point in the right direction, 3-axis (non-spinning) control allows direction to be fine tuned. In practice the station will need a spun section attached to a despun section. Crew transfer between the two is tricky. EVA transfer hazardous. And designing a leak-free IVA tunnel with slip rings and airtight bearings is at least a few hundred $M. Plus lots of lost sleep worrying about when the thing will seize or rupture, sometime it WILL do one or the other, or both.
aws@ITI.ORG ("Allen W. Sherzer") (11/13/90)
In article <7154@hub.ucsb.edu>: >Since LLNL is a large lightweight structure it will be subject to high drag, >compared with, say Freedom. This means more reboosting, more propellant Already included in their budgets. They will use (from memory) 3T a year of fuel for this. An alternative they are looking at is a 10KW ion engine which will reduce fuel demand by ~80%. > (already a problem on Freedom), and higher engine duty cycles. Is there any > way they can make it smaller ? An inflatable station could be made smaller for 0G however if they are to maintain artificial gravity, it is about as small as they can get. It's not clear which has more life cycle cost. Crew can be left on a spinning station for a year with no problems. An inflatable station used as a Freedom replacement could be smaller and run at 0G if desired. >There are practical problems with spinning a station. Need to despin every >time EVA is needed, expensive on propellant/power. Nope. The airlock module doesn't rotate. >Structure must carry centrifugal loads, makes it heavier. Already calculated (see the ILC Dover report). Stresses are welll within the strength of the materials used. >Reboost thrusters must be gimballed, Or reboost partially whenever the thrusters point the right way. Either way, this has been considered. >In practice the station will need a spun section attached to a despun >section. As I said, already in there. The airlock is at 0G. >Crew transfer between the two is tricky. EVA transfer hazardous. >And designing a leak-free IVA tunnel with slip rings and airtight bearings is >at least a few hundred $M. Already included in the cost. This has been anticipated, designed, and included in weight as well as cost budgets. >Plus lots of lost sleep worrying about when the >thing will seize or rupture, sometime it WILL do one or the other, or both. If it fails, the access ports closes and locks. There may be a slight drop in pressure in the central core but that would be it. The two ends of the station would also be out of contact with each other until it was fixed. There would be no loss of either sleep or life. Allen -- +---------------------------------------------------------------------------+ |Allen W. Sherzer| I had a guaranteed military sale with ED-209. Renovation | | aws@iti.org | programs, spare parts for 25 years. Who cares if it | | | works or not? - Dick Jones, VP OCP Security Concepts |
jmck@norge.Eng.Sun.COM (John McKernan) (11/14/90)
aws@ITI.ORG ("Allen W. Sherzer") writes: >An inflatable station could be made smaller for 0G however if they are >to maintain artificial gravity, it is about as small as they can get. It's >not clear which has more life cycle cost. Crew can be left on a spinning >station for a year with no problems. >+---------------------------------------------------------------------------+ >|Allen W. Sherzer| I had a guaranteed military sale with ED-209. Renovation | Soviet crews have stayed in orbit for over a year. They have demonstrated that with advanced exercise machinery and lots of exercise it is possbile to return to the Earth after a year in a 0g environment and completely recover. John L. McKernan. jmck@sun.com Disclaimer: These are my opinions but, shockingly enough, not necessarily Sun's -------------------------------------------------------------------------------
aws@ITI.ORG ("Allen W. Sherzer") (11/14/90)
In article <2687@exodus.Eng.Sun.COM>: >> [LLNL Earth Station will require fewer crew changes because >> they provide artificial G] >Soviet crews have stayed in orbit for over a year. They have demonstrated >that with advanced exercise machinery and lots of exercise it is possbile >to return to the Earth after a year in a 0g environment and completely >recover. True but they don't do it as a matter of routine. In a staion with artificial gravity crew endurance is not limited by microgravity. All things being equal a crew in the LLNL Earth Station will not need to be rotated as often as Freedom. Since it will cost several hundred million $$ to do a rotation, this is a major consideration. Allen -- +---------------------------------------------------------------------------+ |Allen W. Sherzer| I had a guaranteed military sale with ED-209. Renovation | | aws@iti.org | programs, spare parts for 25 years. Who cares if it | | | works or not? - Dick Jones, VP OCP Security Concepts |
aws@ITI.ORG ("Allen W. Sherzer") (11/15/90)
In article <2732@polari.UUCP>: >>Since LLNL is a large lightweight structure it will be subject to high drag, >+Already included in their budgets. They will use (from memory) 3T a year >+of fuel for this. An alternativ+e they are looking at is a 10KW ion engine >The 3T/yr sounds comparable to Freedom, which is much heavier. Weight is a >precious commodity, and budgeting extra propellant to allow for >high drag is inefficient. Better to reduce the drag. If the LLNL Great Exploration plan is enacted, this will not be a problem. The Earth Station will be next to several hundred tons of fuel. A few years after launch, the lunar base will begin returning fuel from the moon. These guys will have fuel coming out of their ears. However, if they are using the same amount of fuel as Freedom then there shouldn't be a problem. >Also increases risk. The LLNL will decay faster than Freedom if its untried >ferry craft becomes grounded. First of all, since you don't know the Earth Station orbit, I don't see how you can make that claim. Second of all, who cares if the ferry becomes grounded? Since the Earth Station provides artificial gravity the crew can stay up for arbitrary amounts of time. We send up fuel/consumables on ELV's (at less cost than the Shuttle) and wait it out. >Ion engines are a high cost item apparently not included in their baseline >price. Correct. It is just an example of their constant attention to potential cost reductions. >> (already a problem on Freedom), and higher engine duty cycles. Is there any >> way they can make it smaller ? >+An inflatable station could be made smaller for 0G however if they are >+to maintain artificial grav+ity, it is about as small as they can get. It's >Sounds like an inherent disadvantage for stations with artifical gravity. To me it is an advantage. They provide a great lab for researching any level of gravity from 0 to 1G. Crews can stay up longer periods and cut billions of $$ from lifetime logistics costs. >That is not the point. Any material can carry any load, if it has big >enough cross section. It is a question of how heavy it has to be to get low >enough stress. Structure carrying centrifugal loads is heavier than >structure which does not. As I said, it is all calculated in (see the ILC report). > Why exactly do LLNL want to spin the thing anyway ? I have already said: more research can be conducted and crews/equipment can be qualified for the moon and Mars. It also allows crews to stay up longer which saves billions in lifecycle cost. >I cannot see any advantage where crews are rotated every 90 days. Why am I not suprised that a Freedom engineer doesn't think saving money is a good reason to do something? :-) >And half the fun for the astronauts is the zero-gee.... They aren't there to have fun. However, there is a zero gee module in the Earth Station. They can have fun there. >>In practice the station will need a spun section attached to a despun >>section. >+As I said, already in there. The airlock is at 0G. >I would still want to despin the station for EVA which could be fairly often. And they don't. >Cannot risk losing an astronaut. Then don't send them up. >Or else LLNL will have to give all their EVA >crew Manouevering Units; Why? Allen -- +---------------------------------------------------------------------------+ |Allen W. Sherzer| I had a guaranteed military sale with ED-209. Renovation | | aws@iti.org | programs, spare parts for 25 years. Who cares if it | | | works or not? - Dick Jones, VP OCP Security Concepts |
jwm@wdl76.wdl.fac.com (Jon W Meyer) (11/15/90)
crad@polari.UUCP (Charles Radley) writes: >13140 >Article 13140 (72 more) in sci.space: > >>Since LLNL is a large lightweight structure it will be subject to high drag, >>compared with, say Freedom. This means more reboosting, more propellant >+Already included in their budgets. They will use (from memory) 3T a year >+of fuel for this. An alternativ+e they are looking at is a 10KW ion engine >+which will reduce fuel demand by ~80%. >- >The 3T/yr sounds comparable to Freedom, which is much heavier. Weight is a >precious commodity, and budgeting extra propellant to allow for >high drag is inefficient. Better to reduce the drag. Just speculation, but although the lighter station is more susceptable to drag, wouldn't the lighter weight also be a benefit? What I'm talking about is that it will take less fuel to accelerate a lighter station X meters per second than it would to accelerate the heavier station by the same amount. Perhaps these effects could balance each other, leading to comparable fuel budgets for the two stations? Comments? Jon
eempa@iceman.jcu.oz (M Parigi) (11/15/90)
> In article <2732@polari.UUCP>: In article <9011142140.AA02302@iti.org>, aws@ITI.ORG ("Allen W. Sherzer") writes: > > >>In practice the station will need a spun section attached to a despun > >>section. > >+As I said, already in there. The airlock is at 0G. > > >I would still want to despin the station for EVA which could be fairly often. > > And they don't. > Allen I don't know about you, but if I were an astronaut doing an EVA to fix a section of the rotating platform (from damage by space flotsam) and had to get out to the 1 g region, I would first have to spin my body, climb down the rotating station hanging on to it for dear life, with the whole universe and earth rotating at 4 times per second above your head, with an uncomfortable suit on, I certainly wouldn't be in any mood to do any work! I think if the kevlar shell did get damaged, the only way to get a human on the outside of the spinning section would be to have it despun! Have you thought about this, Allen? Marco, JCUNQ, oz. Disclaimer: I admit it, this isn't in my university's best interests.
crad@polari.UUCP (Charles Radley) (11/15/90)
+All things being equal a crew in the LLNL Earth Station will +not need to be rotated as often as Freedom. Since it will cost +several hundred million $$ to do a rotation, this is a major +consideration. - US Law allows radiation dose up to 3 rem per calendar quarter for any worker (29 CFR 1910.96 (b)) provided the lifetime dose is not exceeded. LLNL is presumably governed by AEC and/or DOE and State of California radiation regulations which may be different, probably more stringent. This may determine rotation times, rather than 0-g, and would negate the benefit of artifical G. If 90 days is the limit, no point in spinning the station. The Soviets operate at lower altitudes than Freedom is planning, so their radiation exposure is less. Plus they probably allow a higher accumulated dose than US. Going off-line, this will be my last post until ca 27 Nov, flamethrowers please note. I shall return O<~
jmaynard@thesis1.hsch.utexas.edu (Jay Maynard) (11/15/90)
In article <1250@iceman.jcu.oz> eempa@iceman.jcu.oz (M Parigi) writes: > I don't know about you, but if I were an astronaut doing an EVA to fix >a section of the rotating platform (from damage by space flotsam) and had to >get out to the 1 g region, I would first have to spin my body, climb down >the rotating station hanging on to it for dear life, with the whole universe >and earth rotating at 4 times per second above your head, with an uncomfortable >suit on, I certainly wouldn't be in any mood to do any work! I think if the >kevlar shell did get damaged, the only way to get a human on the outside of >the spinning section would be to have it despun! > Have you thought about this, Allen? ...For a literary treatment of just such a subject, see Heinlein's short story, "Ordeal in Space," in _The Past Through Tomorrow_. After reading that, you wouldn't get _me_ out to the end of LLNL's spinning hot dog on the outside... -- Jay Maynard, EMT-P, K5ZC, PP-ASEL | Never ascribe to malice that which can jmaynard@thesis1.hsch.utexas.edu | adequately be explained by stupidity. "With design like this, who needs bugs?" - Boyd Roberts
henry@zoo.toronto.edu (Henry Spencer) (11/15/90)
In article <1990Nov14.223219.17751@wdl1.wdl.fac.com> jwm@wdl76.wdl.fac.com (Jon W Meyer) writes: >Just speculation, but although the lighter station is more susceptable to >drag, wouldn't the lighter weight also be a benefit? What I'm talking >about is that it will take less fuel to accelerate a lighter station >X meters per second than it would to accelerate the heavier station by >the same amount. Perhaps these effects could balance each other... It turns out that the mass of the station is entirely irrelevant, to a good first approximation, to the reboost fuel requirements. A heavier station needs more fuel to reboost but needs it less often. The requirement is that the thrust of the reboost engines, averaged over the period between reboosts, equal the average air-drag forces. Said forces are influenced heavily by frontal area and somewhat by shape but not at all by mass. Other things being equal -- which they probably aren't -- the LLNL station will probably need somewhat more reboost fuel because it is bigger. However, I dimly recall that it is meant for a somewhat higher altitude, which will help. Its spin will also help; Fred, in a gravity-gradient orientation, would always be broadside-on to the "slipstream", while the LLNL station will spend much of its time at an angle. -- "I don't *want* to be normal!" | Henry Spencer at U of Toronto Zoology "Not to worry." | henry@zoo.toronto.edu utzoo!henry