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Space Forum / Shuttle / April 2007NASA Targets June Launch for Space Shuttle Atlantis
April 10, 2007 Allard Beutel Headquarters, Washington 202-358-4769 Kyle Herring Johnson Space Center, Houston 281-483-5111 RELEASE: 07-83 NASA TARGETS JUNE LAUNCH FOR SPACE SHUTTLE ATLANTIS WASHINGTON - NASA is targeting June 8 as the next possible launch opportunity for space shuttle Atlantis' STS-117 mission to the International Space Station. Tuesday's decision by agency management followed a meeting that reviewed the progress in repairing insulating foam on the shuttle's external fuel tank, which was damaged during a sudden hail storm Feb. 26 at NASA's Kennedy Space Center, Fla. That damage required engineers to repair approximately 2,660 sites on the tank. The meeting also included an assessment of using the repaired external tank for the STS-117 mission versus swapping to one that arrived last week from the manufacturing plant in New Orleans. Managers decided to finish repairs to Atlantis' current tank and use it for STS-117. The tank that arrived Friday will be prepared for space shuttle Endeavour's STS-118 mission to the space station and now is targeted for launch in August. "The workforce has done an amazing job of assessing and repairing the tank so far, but the sheer volume of repairs dictates moving the launch target to June," said Space Shuttle Program Manager Wayne Hale. June 8 is the opening of the next available launch window for Atlantis to go to the station. STS-117 Commander Rick Sturckow, Pilot Lee Archambault and mission specialists Jim Reilly, Patrick Forrester, Steven Swanson and John "Danny" Olivas will continue training at NASA's Johnson Space Center, Houston. During the 11-day mission, the astronauts will work with the station crew and ground teams to install a new, girder-like truss segment, unfold a new set of solar arrays and retract one array on the starboard side of the station. For more information about the STS-117 crew and mission, visit: http://www.nasa.gov/shuttle -end- On Apr 11, 1:00?pm, baa...@earthlink.net wrote: > April 10, 2007 > [quoted text clipped - 49 lines] > > -end- 2010 end date POOF GONE! > Endeavour's STS-118 mission to the space station and now is targeted > for launch in August. Unless the decision to extend the Shuttle's graveyard 2010 deadline has already been taken (secretly) NASA cannot afford to postpone launches by months. Wasnt 118 supposed to go in late June ? What would prevent NASA from launching Atlantis on june 8th and Endeavour at end of June ? John Doe <jdoe@doe.org> wrote in news:89322$461d7eca$cef8887a$28578 @TEKSAVVY.COM: >> Endeavour's STS-118 mission to the space station and now is targeted >> for launch in August. [quoted text clipped - 7 lines] > What would prevent NASA from launching Atlantis on june 8th and > Endeavour at end of June ? LON rescue flight capability. The next orbiter won't be ready in time to rescue 118 if Endeavour launches that early. That's the reality with a three orbiter fleet as long as LON capability is a program requirement.  SignatureJRF Reply-to address spam-proofed - to reply by E-mail, check "Organization" (I am not assimilated) and think one step ahead of IBM. > LON rescue flight capability. The next orbiter won't be ready in time to > rescue 118 if Endeavour launches that early. That's the reality with a > three orbiter fleet as long as LON capability is a program requirement. Would it be correct to state that unless the 2010 deadline is extended, the odds of being able to complete the station are now next to nil since there is no means to catch up on a delay ? (especially since the fleet will eventually drop to 2 orbiters). Are there realistic people at NASA that would know the odds of being able to make all missiosn before 2010 ? If the US government changes on January 17th 2009, would that be too late already to declare that the shuttle fleet, having been idle for longer than expected could safely complete the number of flights that had been allowed by the CAIB ? Or would that already be beyond the point of no return in terms of NASA contracts and already dismantling infrastructure to ensure the SHUTTLE can't fly beyond 2010 (isn't that what some people within NASA want to do ?) If ATV is succesful, would then be able to perhaps cut one of the ULF flights still on the roster ? Or are the logistics so tied to specific ships that it would not do any good ? >> LON rescue flight capability. The next orbiter won't be ready in time to >> rescue 118 if Endeavour launches that early. That's the reality with a [quoted text clipped - 21 lines] > flights still on the roster ? Or are the logistics so tied to specific > ships that it would not do any good ? Isn't there a fall-back plan to complete a more limited ISS? Or is it a case of finish it completely or it's useless? (Of course some might say it's useless anyway!) > >> LON rescue flight capability. The next orbiter won't be ready in time to > >> rescue 118 if Endeavour launches that early. That's the reality with a [quoted text clipped - 28 lines] > > - Show quoted text - actually the delays are great for nasa....... the latest schedule shows about a 5 year no manned US launcher....... too many lay poffs that way. way better to see delay after delay all necessary, then continue ISS till station complete or another accident ends the program. >> LON rescue flight capability. The next orbiter won't be ready in time >> to rescue 118 if Endeavour launches that early. That's the reality [quoted text clipped - 4 lines] > extended, the odds of being able to complete the station are now next > to nil since there is no means to catch up on a delay ? No. There is still some margin in the schedule. 118 slipped but not as much as 117. 120 slipped but not as much as 118. The slips from 117 are pretty much absorbed by the time you get to 125. And if future slips occur, there are two contingency logistics flights at the end of the manifest (131/ULF-4 and 133/ULF-5) that could be cancelled, if need be, without impacting station assembly. > Are there realistic people at NASA that would know the odds of being > able to make all missiosn before 2010 ? No, there are no psychics or clairvoyants at NASA. > If the US government changes on January 17th 2009, The only way that would happen is a coup d'etat. Inauguration day is January 20. > would that be too > late already to declare that the shuttle fleet, having been idle for [quoted text clipped - 5 lines] > SHUTTLE can't fly beyond 2010 (isn't that what some people within NASA > want to do ?) The termination of contracts would make it very difficult to add new flights to the manifest. It would not be difficult to stretch the existing manifest past the end of FY2010. > If ATV is succesful, would then be able to perhaps cut one of the ULF > flights still on the roster ? Or are the logistics so tied to specific > ships that it would not do any good ? The logistics carriers on ULF-4 and 5 are external, and would not fit through the ATV hatches. They could be carried by ATV with modifications, but a better bet would be a modified HTV since the logistics carriers were designed to be handled by the SSRMS, and the SSRMS has better reach at the HTV than the ATV. SignatureJRF Reply-to address spam-proofed - to reply by E-mail, check "Organization" (I am not assimilated) and think one step ahead of IBM. >> If the US government changes on January 17th 2009, > >The only way that would happen is a coup d'etat. Don't give the Lefties any ideas, Jorge... They hate Bush so much they're not thinking straight as it is. Brian >> The only way that would happen is a coup d'etat. > > Don't give the Lefties any ideas, Jorge... They hate Bush so much > they're not thinking straight as it is. Many of us left-leaning centrists hate Bush for being an imbecilic draft-dodging hypocrite, hate his handlers for being evil, inept kleptocrats intent in crushing the middle class, and we're thinking quite clearly, thank you. :-) > Brian SignatureYou can run on for a long time, Sooner or later, God'll cut you down. ~Johnny Cash >>> If the US government changes on January 17th 2009, >> >>The only way that would happen is a coup d'etat. > > Don't give the Lefties any ideas, Jorge... They hate Bush so much > they're not thinking straight as it is. I think you need to up your meds Brian. Thanks for the nice generalization. Says a lot about your character. > Brian SignatureGreg Moore SQL Server DBA Consulting Remote and Onsite available! Email: sql (at) greenms.com http://www.greenms.com/sqlserver.html On Fri, 13 Apr 2007 20:37:40 GMT, "Greg D. Moore \(Strider\)" <mooregr_deleteth1s@greenms.com> wrote: >> Don't give the Lefties any ideas, Jorge... They hate Bush so much >> they're not thinking straight as it is. >Thanks for the nice generalization. Says a lot about your character. Hey, even Herb (whom I respect) is calling the Bush Administration "evil". I'm sorry if you're offended, but I call 'em as I see 'em: Lefties are blind with hatred of Bush. It makes the Right's 8-year vendetta against Bill "It depends on what the meaning of 'is' is" Clinton look like mild annoyance. At least Gingrich *spit!* and Co. let Clinton get a few things done. Nowadays, if Bush were to say the sky is blue, the Dems on Capitol Hill would grandstand before the cameras to say he's lying, demand the emails to find out who made up the lie about the sky being blue, and then cut off funds to NASA and NOAA until Bush admits the sky is not, in fact, blue. And half the country will applaud them for this brilliant demonstration of checks and balances in government. Okay, there might be a few Lefties who still think clearly and realize Bush & Co. are not evil, warmongering kleptomaniacs, but they appear to be in hiding. :-) Brian > Okay, there might be a few Lefties who still think clearly and realize > Bush & Co. are not evil, warmongering kleptomaniacs, but they appear > to be in hiding. :-) Well, warmongering is one thing, but screwing up Iraq is another. And we can't just bail out like we did with Vietnam. Vietnam had no oil or anything else of value... And the clowns running North Korea, Iran and Sudan know that our plate is full... > Hey, even Herb (whom I respect) is calling the Bush Administration > "evil". I'm sorry if you're offended, but I call 'em as I see 'em: > Lefties are blind with hatred of Bush. Let's be precise: I said his handlers are "evil, inept kleptocrats intent in crushing the middle class." :-) SignatureYou can run on for a long time, Sooner or later, God'll cut you down. ~Johnny Cash > > What would prevent NASA from launching Atlantis on june 8th and > > Endeavour at end of June ? > > LON rescue flight capability. The next orbiter won't be ready in time to > rescue 118 if Endeavour launches that early. That's the reality with a > three orbiter fleet as long as LON capability is a program requirement. Unfortunately, the requirement for a rescue flight also means we'll never see two shuttles in orbit at the same time. THAT would be a publicity stunt I'd love to watch. Op Thu, 12 Apr 2007 00:18:29 -0700, schreef Hyper: > Unfortunately, the requirement for a rescue flight also means we'll > never see two shuttles in orbit at the same time. Unless of course when a real rescue flight must be done. > THAT would be a publicity stunt I'd love to watch. Are you sure? > Op Thu, 12 Apr 2007 00:18:29 -0700, schreef Hyper: > [quoted text clipped - 6 lines] > > Are you sure? Ironically, the very capabilities that made the STS so attractive to begin with is leading to it's demise. I think the Shuttle is a classic example of how any system can become too complicated to manage effectively or efficiently. George > Ironically, the very capabilities that made the STS so attractive to begin > with is leading to it's demise. I think the Shuttle is a classic example > of how any system can become too complicated to manage effectively or > efficiently. This is an oversimplification. The design was compromised in many ways in order to keep development costs and schedule under control. While development costs were kept to reasonable levels, the resulting design was deficient in many areas. For example, the payload goal wasn't met. Over the years, several changes were made to increase payload (e.g. the ET redesigns). Unfortunately, many of the lessons learned have never led to redesigns to remove deficiencies. NASA really wanted to get rid of things like the SRB's and the hypergolic propellants, but never had enough budget to do so. At this point the shuttle is seen as a failure on many levels so NASA is retreating back to an Apollo like design for Orion. Unfortunately, they've also decided on building Ares I and V instead of using existing EELV's, which I think will turn out to be a big mistake in the long term. Jeff Signature"They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety" - B. Franklin, Bartlett's Familiar Quotations (1919) On Apr 12, 6:41 pm, "Jeff Findley" <jeff.find...@ugs.nojunk.com> wrote: > At this point the shuttle is seen as a failure on many levels so NASA is > retreating back to an Apollo like design for Orion. Unfortunately, they've > also decided on building Ares I and V instead of using existing EELV's, > which I think will turn out to be a big mistake in the long term. > > Jeff It's damn mindboggling. If they couldn't go with something like Shuttle C there was still the option of using existing hardware (a la Direct) and an EELV for crew capsules & ISS resuply. All the money pissed away on supposedly Shuttle derived hardware could have easily bought LRBs or maybe an OTV. > On Apr 12, 6:41 pm, "Jeff Findley" <jeff.find...@ugs.nojunk.com> > wrote: [quoted text clipped - 12 lines] > All the money pissed away on supposedly Shuttle derived hardware could > have easily bought LRBs or maybe an OTV. yeah pork at its worst, waste design money, then be tied to a dedicated low flight rate booster, that when it devlops a problem you grounded, that long term will cost more, better to go on existing expendables, and would of been flying sooner too. typical federal program waste, tossing our money to the politically connected:( >> Op Thu, 12 Apr 2007 00:18:29 -0700, schreef Hyper: >> [quoted text clipped - 11 lines] > of how any system can become too complicated to manage effectively or > efficiently. I agree. I think winged spacecraft are inherently bad for two reasons: 1. The termal protection is fragile and complex. 2. The weather requirements for ascent aborts and end of mission landing are too high I am a big fan of capsules for manned spacecraft. Send the big payloads up without people in a winged vehicle. Wasn't Challanger carrying a TDRS? Why risk life to send up a payload such as this? Danny Deger > George > 2. The weather requirements for ascent aborts and end of mission landing > are too high This isn't because it is a winged vehicle per say. It is because it is a reusable vehicle and the goal is to have it return and land gracefully on a runway, so you need good weather in/around any runway where that vehicle could land. If the shuttle were a disposable vehicle, they'd just eject the crew from it and let it burn up/fall into the ocean. > If the shuttle were a disposable vehicle, they'd just eject the crew > from it and let it burn up/fall into the ocean. Shuttle ORIGINALLY had crew in a escaped pod of sorts which was cut to save weight and $$$ thats why the challenger crew cabin remained largely intact, the heavier crew pod design never saw the extra support deleted, again to save $ I think shuttles would continue flying forever if they didnt KILL astronauts........... Killing people ultimately is killing the program >> If the shuttle were a disposable vehicle, they'd just eject the crew >> from it and let it burn up/fall into the ocean. [quoted text clipped - 3 lines] > largely intact, the heavier crew pod design never saw the extra > support deleted, again to save $ No. One plan out of MANY had an escape pod. > I think shuttles would continue flying forever if they didnt KILL > astronauts........... > > Killing people ultimately is killing the program SignatureGreg Moore SQL Server DBA Consulting Remote and Onsite available! Email: sql (at) greenms.com http://www.greenms.com/sqlserver.html > > Shuttle ORIGINALLY had crew in a escaped pod of sorts which was cut to > > save weight and $$$ thats why the challenger crew cabin remained > > largely intact, the heavier crew pod design never saw the extra > > support deleted, again to save $ > > No. One plan out of MANY had an escape pod. It was part of the original design specs and thats why the crew cabin held together after the challenger accident. WAY too many compromises were made with the shuttles:( If they had stuck with crew escape, liquid flyback boosters, and gotten rid of the hydrazine operating expense and risk would of greatly improved > > Shuttle ORIGINALLY had crew in a escaped pod of sorts which was cut to > > save weight and $$$ thats why the challenger crew cabin remained > > largely intact, the heavier crew pod design never saw the extra > > support deleted, again to save $ > > No. One plan out of MANY had an escape pod. It was part of the original design specs and thats why the crew cabin held together after the challenger accident. WHICH original design specs. Put up or shut up Bob. And no, the reason it held together after Challenger was due to the fact that it has to be strong to be a pressure vessel. WAY too many compromises were made with the shuttles:( If they had stuck with crew escape, liquid flyback boosters, and gotten rid of the hydrazine operating expense and risk would of greatly improved SignatureGreg Moore SQL Server DBA Consulting Remote and Onsite available! Email: sql (at) greenms.com http://www.greenms.com/sqlserver.html "Greg D. Moore \(Strider\)" <mooregr_deleteth1s@greenms.com> wrote in news:QRRTh.21101$PL.12055@newsread4.news.pas.earthlink.net: >>> > Shuttle ORIGINALLY had crew in a escaped pod of sorts which was >>> > cut to save weight and $$$ thats why the challenger crew cabin [quoted text clipped - 10 lines] > And no, the reason it held together after Challenger was due to the > fact that it has to be strong to be a pressure vessel. Correct. Escape pods were among many crew escape concepts that the contractors studied as part of Phase B. None of them made it into the design specs. The Program Definition Document had a rapid egress requirement for the development flight tests, (Jenkins, 3rd ed, p 133) and the bailout pole became a program requirement after 51L, but that's it. SignatureJRF Reply-to address spam-proofed - to reply by E-mail, check "Organization" (I am not assimilated) and think one step ahead of IBM. On Apr 13, 3:00 pm, "hall...@aol.com" <hall...@aol.com> wrote: > > > Shuttle ORIGINALLY had crew in a escaped pod of sorts which was cut to > > > save weight and $$$ thats why the challenger crew cabin remained [quoted text clipped - 11 lines] > gotten rid of the hydrazine operating expense and risk would of > greatly improved The hell? Initially everyone assumed the crew was killed when Challenger broke up, the crew cabin with it. The cabin holding together shows how tough the damn thing is because if in orbit, it's the last thing you want getting breached. Of course the part of the vehicle where people are going to spend around two weeks in shirt-sleeves is going to be among the sturdiest. The only escape plans I ever heard of were for an Apollo-style capsule tucked away in the payload bay. And those loopy "rescue balls" from the 80's. -A.L. > I agree. I think winged spacecraft are inherently bad for two reasons: > > 1. The termal protection is fragile and complex. > 2. The weather requirements for ascent aborts and end of mission landing > are too high Not necessarily. Look at Dynasoar - nothing fragile about that baby. If used as people ferry, it makes sense to trade payload for safety. >> I agree. I think winged spacecraft are inherently bad for two reasons: >> [quoted text clipped - 4 lines] > Not necessarily. Look at Dynasoar - nothing fragile about that baby. > If used as people ferry, it makes sense to trade payload for safety. What is the design of its thermal protection? I am sure it high weather requirements for ascent abort and landing. Danny Deger > >> I agree. I think winged spacecraft are inherently bad for two reasons: > [quoted text clipped - 9 lines] > > Danny Deger Rene41 structure, graphite&zirconium dioxide nose and the bottom was molybdenum sheet. >> I agree. I think winged spacecraft are inherently bad for two reasons: >> [quoted text clipped - 4 lines] > Not necessarily. Look at Dynasoar - nothing fragile about that baby. > If used as people ferry, it makes sense to trade payload for safety. The TPS of Dynasoar wasn't necessarily durable. Since it was metallic, it had to be very thin. I'm sure Scott would have the details... Jeff Signature"They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety" - B. Franklin, Bartlett's Familiar Quotations (1919) > I agree. I think winged spacecraft are inherently bad for two reasons: > [quoted text clipped - 5 lines] > up without people in a winged vehicle. Wasn't Challanger carrying a TDRS? > Why risk life to send up a payload such as this? The reasons you state have little to do with whether a spacecraft is winged or not. They have a lot more to do with other things, like how dense the spacecraft is. How dense it is impacts the TPS requirements. The real weakness is the fragile TPS. By the way, the shuttle is very dense because it drops the lowest density part of a launch vehicle, which is the empty propellant tanks. It keeps the heavy SSME's. If you were designing a sensible reusable launch vehicle, you wouldn't throw away the tanks, which makes the TPS requirements lower. Jeff Signature"They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety" - B. Franklin, Bartlett's Familiar Quotations (1919) >By the way, the shuttle is very dense because it drops the lowest density >part of a launch vehicle, which is the empty propellant tanks. It keeps the >heavy SSME's. If you were designing a sensible reusable launch vehicle, you >wouldn't throw away the tanks, which makes the TPS requirements lower. Certainly in _developing_ a 'sensible' reusable launch vehicle, you'd keep the tanks. But when you got around to actually _designing_ the beast - you'd run into the same problems that caused NASA to back off from that scheme, and which remain unsolved. It's an open question whether they can be solved economically. D. SignatureTouch-twice life. Eat. Drink. Laugh. -Resolved: To be more temperate in my postings. Oct 5th, 2004 JDL fairwater@gmail.com (Derek Lyons) wrote: >Certainly in _developing_ a 'sensible' reusable launch vehicle, you'd >keep the tanks. But when you got around to actually _designing_ the >beast - you'd run into the same problems that caused NASA to back off >from that scheme, and which remain unsolved. > >It's an open question whether they can be solved economically. In 26 years, I've encountered hundreds of variations on "STS turned out to be a lemon because..." Usually followed by 1) Powerpoint handwaving about the True Design Breakthrough 2) Grumbling about short-sighted bean-counters in Congress and OMB 3) Assertions that "of course it was doomed, government screws up everything it touches" The possibility that a "sensible reusable LV" (sensible in economic and operational as well as purely engineering terms) is really, really hard -- and will take a long time, many designs, and many many flights, no matter who pays for it -- seems too frightening for most to contemplate. Monte Davis http://montedavis.livejournal.com >fairwater@gmail.com (Derek Lyons) wrote: > [quoted text clipped - 14 lines] >3) Assertions that "of course it was doomed, government screws up >everything it touches" Agreed. It's all too often tacitly assumed that the approaches NASA didn't take are easy and simple. It simply doesn't register to many people that things like monolithic solids or integral tanks have significant problems of their very own. It's arguable whether NASA evaluated and weighted the advantages and disadvantages of the varied approaches properly - but it's outright lunacy to pretend the disadvantages and potholes on the roads not taken don't exist. >The possibility that a "sensible reusable LV" (sensible in economic >and operational as well as purely engineering terms) is really, really >hard -- and will take a long time, many designs, and many many >flights, no matter who pays for it -- seems too frightening for most >to contemplate. Agreed. Which is why I ended my post the way I did. D. SignatureTouch-twice life. Eat. Drink. Laugh. -Resolved: To be more temperate in my postings. Oct 5th, 2004 JDL >>By the way, the shuttle is very dense because it drops the lowest density >>part of a launch vehicle, which is the empty propellant tanks. It keeps [quoted text clipped - 7 lines] > beast - you'd run into the same problems that caused NASA to back off > from that scheme, and which remain unsolved. You mean the military requirements for a large payload bay and around 60k lbs payload? Or do you mean NASA's requiremnt to contain development costs and (somewhat needlessly) constrain the overall vehicle size? At one point, NASA wanted a fully reusable launch vehicle with liquid fueled engines. They certainly didn't move away from that desire because they thought it would make the reoccurring costs lower. > It's an open question whether they can be solved economically. True, it's not been done yet. But the physics involved does seem to favor keeping your empty tanks with your reentry vehicle if one of your design goals is lower TPS requirements than the shuttle. The reason the shuttle ET was designed with a propulsive tumble vent valve is because the designers did not want the ET to remain intact when it reentered. Jeff Signature"They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety" - B. Franklin, Bartlett's Familiar Quotations (1919) > True, it's not been done yet. But the physics involved does seem to favor > keeping your empty tanks with your reentry vehicle if one of your design [quoted text clipped - 3 lines] > is because the designers did not want the ET to remain intact when it > reentered. Titanium Tanks make it to the Earth's surface all the time, with no heat shield. A fast rolling Titanium ET could easily make it to a controlled landing (modifications required), with no heat shield. Keep the hot spot rolling around the entire tank. >> True, it's not been done yet. But the physics involved does seem to favor >> keeping your empty tanks with your reentry vehicle if one of your design [quoted text clipped - 6 lines] >Titanium Tanks make it to the Earth's surface all the time, with no heat >shield. No _formal_ heat shield, no. But in reality they are at least partly shielded by the structure they reside within for the early portions of reentry. D. SignatureTouch-twice life. Eat. Drink. Laugh. -Resolved: To be more temperate in my postings. Oct 5th, 2004 JDL >>> True, it's not been done yet. But the physics involved does seem to >>> favor keeping your empty tanks with your reentry vehicle if one of your [quoted text clipped - 10 lines] > shielded by the structure they reside within for the early portions of > reentry. Rolling the tank would be like a _formal_ heat shield. The hot spot on the tank soon finds itself in the coolest spot radiating the heat, then back to the hot spot. >>>Titanium Tanks make it to the Earth's surface all the time, with no heat >>>shield. [quoted text clipped - 6 lines] >tank soon finds itself in the coolest spot radiating the heat, then back to >the hot spot. ROTFLMAO. SignatureTouch-twice life. Eat. Drink. Laugh. -Resolved: To be more temperate in my postings. Oct 5th, 2004 JDL >>>>Titanium Tanks make it to the Earth's surface all the time, with no heat >>>>shield. [quoted text clipped - 8 lines] > > ROTFLMAO. lol, what's it called? I guess the BBQ heat shield, roast evenly until done (down). Don't stop, or rotate too slowly, you'll burn one side. > lol, what's it called? I guess the BBQ heat shield, roast evenly until > done > (down). Don't stop, or rotate too slowly, you'll burn one side. http://www.aiaa.org/content.cfm?pageid=406&gTable=mtgpaper&gID=66838 Click on the link to the "first page" and look what was proposed by the author of the above AIAA paper. Jeff Signature"They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety" - B. Franklin, Bartlett's Familiar Quotations (1919) >> lol, what's it called? I guess the BBQ heat shield, roast evenly until >> done [quoted text clipped - 4 lines] > Click on the link to the "first page" and look what was proposed by the > author of the above AIAA paper. Just did, http://adsabs.harvard.edu/cgi-bin/nph-basic_connect?qsearch=+Space+Shuttle+exter nal+tank+as+a+re-entry+module&version=1 here too, abstract only. Looks like it's $25 to read, or a trip to a good library to find out what he called the mode. > Just did, > http://adsabs.harvard.edu/cgi-bin/nph-basic_connect?qsearch=+Space+Shuttle+exter nal+tank+as+a+re-entry+module&version=1 [quoted text clipped - 3 lines] > he > called the mode. Yep. With AIAA papers, it's usually hard to tell what you're going to get without looking at the entire paper. It could have included a fairly in depth analysis by someone who knew what they were doing, or it could have been done by someone going for their Masters degree in engineering and on top of that they might have had a really bad professor sponsoring them. :-/ It's times like this I wish I were still back at Purdue where looking up this sort of thing was relatively quick and easy. You just had to know which of the dozens of libraries on campus would carry AIAA papers. :-) Jeff Signature"They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety" - B. Franklin, Bartlett's Familiar Quotations (1919) > >>>>Titanium Tanks make it to the Earth's surface all the time, with no heat > >>>>shield. [quoted text clipped - 13 lines] > > - Show quoted text - A tank coud end up in orbit, if say it didnt seperate for some reason. its a interesting disaster idea > The reason the shuttle ET was designed with a propulsive tumble vent valve > is because the designers did not want the ET to remain intact when it > reentered. I've always wondered what it would take to make an ET survive re-entry. Put some sort of stabilization on it, chute for landing? Would the existing SOFI work well enough as a ablative shield of some sort? Even as a demo it could be interesting. I mean the tank is sort of the epitome of what people describe as ideal for re-entry, very light but massive. > Jeff SignatureGreg Moore SQL Server DBA Consulting Remote and Onsite available! Email: sql (at) greenms.com http://www.greenms.com/sqlserver.html > I've always wondered what it would take to make an ET survive re-entry. > [quoted text clipped - 6 lines] > epitome of what people describe as ideal for re-entry, very light but > massive. I think you'd end up making it out of Titanium, didn't a large percentage of the Aluminum from Columbia burn up in the atmosphere. I think a better demo that would be interesting would be to take it to orbit. Let a little robot grind it up, put it in a thin steal container, then heat it up. Make a molten aluminum/lithium ball, then try to blow it into a huge hollow sphere as it cools. Like glass blowing, but with Aluminum. Could probably do it over and over again with the same aluminum until the proper technique is developed. A 50,000 lbs spherical habitat, doors and windows optional. If the Space Station drops down into a little bit lower orbit, they might get to the break even point. Where it cost nothing to take it the rest of the way to the Station. What was it Reagan said, something about free ETs in Orbit? >> I've always wondered what it would take to make an ET survive re-entry. >> [quoted text clipped - 10 lines] > of > the Aluminum from Columbia burn up in the atmosphere. You're totally missing the point! Since the ET is mostly empty space, much of its decelleration happens higher up in the atmosphere so the heating is a lot less than the very dense orbiter experiences. Jeff Signature"They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety" - B. Franklin, Bartlett's Familiar Quotations (1919) > You're totally missing the point! Since the ET is mostly empty space, > much of its decelleration happens higher up in the atmosphere so the > heating is a lot less than the very dense orbiter experiences. No, I didn't miss that point, but your both right. It would be fun demo too. Even without the parachute to see is a fast rolling stable ET would make it to splashdown. Maybe the SOFI would char and radiate enough to make it down? But I still thing it's just better to keep it up there and use it instead. I also doubt you missed that point. >> You're totally missing the point! Since the ET is mostly empty space, >> much of its decelleration happens higher up in the atmosphere so the [quoted text clipped - 10 lines] > I > also doubt you missed that point. The program is set to end after 2010. We'll see an ET in orbit when pigs fly! Jeff Signature"They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety" - B. Franklin, Bartlett's Familiar Quotations (1919) "Greg D. Moore \(Strider\)" <mooregr_deleteth1s@greenms.com> wrote: >I've always wondered what it would take to make an ET survive re-entry. >Put some sort of stabilization on it, chute for landing? > >Would the existing SOFI work well enough as a ablative shield of some sort? My gut feeling is no - not for a reentry from LEO. And even so - are the 'ridges' on the intertank structure 'tall enough' to disrupt the boundary layer? The extreme nose is less insulated - what happens to it? D. SignatureTouch-twice life. Eat. Drink. Laugh. -Resolved: To be more temperate in my postings. Oct 5th, 2004 JDL > "Greg D. Moore \(Strider\)" <mooregr_deleteth1s@greenms.com> wrote: >> [quoted text clipped - 9 lines] > enough' to disrupt the boundary layer? The extreme nose is less > insulated - what happens to it? Good questions. (Where's Mary or Henry when we need them? :-) I suspect a stock tank wouldn't cut it. But I wonder if you were willing to sacrifice a little payload, what changes you could make to make it worthwhile? I wonder if it was ever looked at. > D. >> "Greg D. Moore \(Strider\)" <mooregr_deleteth1s@greenms.com> wrote: >>> [quoted text clipped - 18 lines] > > I wonder if it was ever looked at. http://www.aiaa.org/content.cfm?pageid=406&gTable=mtgpaper&gID=66838 From the above page: The Space Shuttle external tank as a re-entry module KENT, S. (Aerojet Liquid Rocket Co., Sacramento, Calif.) AIAA-1979-888 In: Conference on Advanced Technology for Future Space Systems, Hampton, Va., May 8-10, 1979, Technical Papers. (A79-34701 14-12) New York, American Institute of Aeronautics and Astronautics, Inc., 1979, p. 159-164. If you click on the link to the "first page" of the PDF, you'll find that stabilization of the orientation of the tank (so that it's got its "side" facing the direction of flight) and rotation of the tank to reduce the stagnation heating (by approximately a factor of two) are proposed as methods of reducing entry heating. This is only an AIAA paper, but it does show that someone was thinking about this in the 70's. Jeff Signature"They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety" - B. Franklin, Bartlett's Familiar Quotations (1919) >>> "Greg D. Moore \(Strider\)" <mooregr_deleteth1s@greenms.com> wrote: >>>> [quoted text clipped - 40 lines] > This is only an AIAA paper, but it does show that someone was thinking > about this in the 70's. Yep, that looks exactly like what I was talking about, a BBQ heat shield. I guess you have to read the whole paper to see if he named it. It looks like it has your answer, 50% reduction in max temperature, good bye Aluminum, hello Titanium. >> This is only an AIAA paper, but it does show that someone was thinking >> about this in the 70's. [quoted text clipped - 5 lines] > it has your answer, 50% reduction in max temperature, good bye Aluminum, > hello Titanium. I don't have the paper myself, but that first page said the assumption was made that the tank material was duraluminum. I have no idea how the current AlLi material compares to duraluminum. The main thing to note is the orientation of the tank for reentry. That's a lot of frontal area for an object that weighs about 34,000 kg. I believe the orbiter landing mass is something like 104,000 kg max. The ET has about 1/3 of the mass but what looks like (more or less) a similar frontal area facing the direction of motion (i.e. the bottom of the orbiter). In other words, the ET will decelerate faster, higher up in the atmosphere, so the reentry heating should be a lot less than on the orbiter. Jeff Signature"They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety" - B. Franklin, Bartlett's Familiar Quotations (1919) >>> This is only an AIAA paper, but it does show that someone was thinking >>> about this in the 70's. [quoted text clipped - 20 lines] > atmosphere, so the reentry heating should be a lot less than on the > orbiter. He even has the Roll rotation right, like a baseball, to get a little bit of lift to stay up high. It still has the same amount of energy to dissipate. During the initial part of entry, the heat rate may not be very large, but the temperatures are extreme. Stick your hand out in the flow, it won't be blown back (no dynamic pressure), but will roast. Parts of Columbia began coming off quite early. I wonder if he ran the case to maximize the temperature drop, an extreme roll rate. You got 25 buck that you don't care about? I'll mail your copy back after reading it. >In other words, the ET will decelerate faster, higher up in the atmosphere, >so the reentry heating should be a lot less than on the orbiter. IIRC the tradeoff for lower peak heating is a much longer heating period - there's still a considerable amount of energy to dissipate. D. SignatureTouch-twice life. Eat. Drink. Laugh. -Resolved: To be more temperate in my postings. Oct 5th, 2004 JDL > IIRC the tradeoff for lower peak heating is a much longer heating > period - there's still a considerable amount of energy to dissipate. The ET will not take longer to reenter than the orbiter. It should take less time. Duration of reentry is a function of the L/D ratio, not the ballistic coefficient (mass/area). The latter controls the altitude at which the reentry is performed, though. Pauk >>In other words, the ET will decelerate faster, higher up in the atmosphere, >>so the reentry heating should be a lot less than on the orbiter. > > IIRC the tradeoff for lower peak heating is a much longer heating > period - there's still a considerable amount of energy to dissipate. Let that energy heat up the residual hydrogen in the tank and vent this through valves to achieve a kind of film cooling, protecting the surface and carrying the heat away... Jochem Signature"A designer knows he has arrived at perfection not when there is no longer anything to add, but when there is no longer anything to take away." - Antoine de Saint-Exupery >If you click on the link to the "first page" of the PDF, you'll find that >stabilization of the orientation of the tank (so that it's got its "side" >facing the direction of flight) and rotation of the tank to reduce the >stagnation heating (by approximately a factor of two) are proposed as >methods of reducing entry heating. The various and sundry bits of hardware on the Orbiter side are going to cause problems. Ditto the ridged surface of the intertank structure. It would be interesting to see if those were addressed. Another unanswered question whether a factor of two reduction of stagnation temperature is sufficient to bring stagnation temperature within the range that the SOFI will withstand. (Both of this assume that the method will actually work.) D. SignatureTouch-twice life. Eat. Drink. Laugh. -Resolved: To be more temperate in my postings. Oct 5th, 2004 JDL >This is only an AIAA paper, but it does show that someone was thinking about >this in the 70's. > >Jeff My library at work has it in PDF! I wouldn't hang my hat on this paper. A few highlights (pardon the poor OCR spacing): Under "Assumptions and Their Consequences" The model used i n t h i s analysis was assumed to be a perfectly smooth cylinder. The SSET is far from smooth; numerous pipes and s t r u t s form protrubances likely to experience heating far in excess o f t h e s t a g n a t i o n region heating. It is possible t h a t f a i l u r e o f t h e tank could r e s u l t from s t r u c t u r a l weakening caused by the d i s i n t e - g r a t i o n of an appendage experiencing highly l o c a l i z e d heating. Only f u r t h e r study w i l l r e v e a l t h e f u l l extent o f the problem, i f indeed there is a problem. Even i f the assumption of a smooth surface for the SSET is i n e r r o r , and it looks unlikely t h a t an i r r e g u l a r external tank could survive re-entry, a l l is not l o s t . I n situat i o n s such as these, it is well advised engineering p r a c t i s e to make r e a l i t y conform to the analysis model and make t h e s u r f a c e o f t h e SSET smooth. This could be e a s i l y accomplished during t h e i n - o r b i t r e t r o f i t o f t h e tank. A spray-on foam i n s u l a t i o n could be applied by a t e l e o p e r a t o r device while payload is being loaded i n t o t h e t a n k. Under "Towards the Future" A s is t h e conclusion of most f e a s i - b i l i t y s t u d i e s , f u r t h e r study is recommended. It may be economically i n f e a s i b l e t o r e - e n t e r payload i n the otherwise u s e l e s s e x t e r n a l tank because of the high i n d i r e c t c o s t s of recovery. If t h i s is t h e case, t h e r e is one f i n a l j u s t i f i c a t i o n f o r ree n t e r i n g t h e e x t e r n a l tank; consider t h e money to be made from t u r n i n g r e - e n t e r e d SSET's i n t o r a t h e r unique r e s t a u r a n t s . If people a r e w i l l i n g t o e a t i n o l d r a i l r o a d c a r s , p o t e n t i a l space e n t r e p r e n e u r s could make q u i t e a business o u t o f s e a t i n g hungry d i n e r s i n t h e i n s i d e s of what was once t r a v e l l i n g a t Mach t h i r t y ! Who, besides the people reading these groups, want to eat is a resturant that has flown at Mach 30? --Rolf > Who, besides the people reading these groups, want to eat is a > restaurant that has flown at Mach 30? lol, looks like he got it right to me. Restaurant, Swimming pool, 3-D Basketball court, Garden module, LEO Commodities Futures Market ... Why turn a 500 Million dollar tank in LEO back into a 4 Million dollar tank on the ground? Add a parachute, and the tank is negative sitting back on the ground, real quick. > > Who, besides the people reading these groups, want to eat is a > > restaurant that has flown at Mach 30? [quoted text clipped - 5 lines] > on the ground? Add a parachute, and the tank is negative sitting back on > the ground, real quick. except as a exhibit, a flown tank would be a tourist attraction, with it mated to a real orbiter, and 2 flown SRBs >Who, besides the people reading these groups, want to eat is a >resturant that has flown at Mach 30? Not only that - but the fad for eating in converted railroad cars in long dead. D. SignatureTouch-twice life. Eat. Drink. Laugh. -Resolved: To be more temperate in my postings. Oct 5th, 2004 JDL "Greg D. Moore \(Strider\)" <mooregr_deleteth1s@greenms.com> wrote: >But I wonder if you were willing to sacrifice a little payload, what changes >you could make to make it worthwhile? None. I.E. the tanks are cheap enough that they aren't worth the expense of recovery. D. SignatureTouch-twice life. Eat. Drink. Laugh. -Resolved: To be more temperate in my postings. Oct 5th, 2004 JDL > "Greg D. Moore \(Strider\)" <mooregr_deleteth1s@greenms.com> wrote: > [quoted text clipped - 6 lines] > I.E. the tanks are cheap enough that they aren't worth the expense of > recovery. Right, assuming it's a purely commercial venture, which you know the Shuttle isn't. I'm talking about more as a research project. (but as I recall the tank was generally the single lost incremental cost in shuttle flights...) > D. SignatureGreg Moore SQL Server DBA Consulting Remote and Onsite available! Email: sql (at) greenms.com http://www.greenms.com/sqlserver.html >>>By the way, the shuttle is very dense because it drops the lowest density >>>part of a launch vehicle, which is the empty propellant tanks. It keeps [quoted text clipped - 8 lines] >You mean the military requirements for a large payload bay and around 60k >lbs payload? Eventually you are going to want that same cargo bay and payload, whether you are DoD or not. (Especially if your goal is to reduce costs.) >Or do you mean NASA's requiremnt to contain development costs >and (somewhat needlessly) constrain the overall vehicle size? Every real world vehicle is going to have fiscal and infrastructure limits. That's the nature of real world engineering. >At one point, NASA wanted a fully reusable launch vehicle with liquid fueled >engines. They certainly didn't move away from that desire because they thought >it would make the reoccurring costs lower. >> It's an open question whether they can be solved economically. > >True, it's not been done yet. I said nothing about whether it's been done yet. >But the physics involved does seem to favor keeping your empty tanks with your >reentry vehicle if one of your design goals is lower TPS requirements than the >shuttle. Design goals are easy to meet on paper. It's somewhat harder to reconcile conflicting design goals (and an internal tank shuttle has a number of conflicts with other reasonable design goals). >The reason the shuttle ET was designed with a propulsive tumble vent valve >is because the designers did not want the ET to remain intact when it >reentered. A half truth at best. Said valve also provides separation impulse and more predictable aerodynamics at entry interface (I.E. a predictable trajectory). Any additional effect in ensuring breakup is (I suspect) a bonus. D. SignatureTouch-twice life. Eat. Drink. Laugh. -Resolved: To be more temperate in my postings. Oct 5th, 2004 JDL |
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