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MSNBC (JimO) on value of 'big door' on ISS
On Sat, 08 Jul 2006 22:01:46 -0400, John Doe wrote:
HTV isn't the only alternative. Out of the six finalists for NASA's Commercial Orbital Transportation Services (COTS) program, four have released at least some details on how their spacecraft will attach to ISS - and all four (Rocketplane Kistler K-1, SpaceX Dragon, Spacehab Apex, and t/Space CxV) have chosen the CBM. OK, that looks great. But In reality, since we're not even sure that CEV will ever get off the ground, why would anyone bet their life on those neat little ideas floating around ? Because if nothing else, the Russians will still happily carry our astronauts up to ISS for a nominal fee. Of course, if CEV is cancelled and Shuttle retires, you can be your bottom dollar that fee will rise substantially... And when could such neat little ideas materialise ? Any chance they would be in production and fully operational by the time the shuttle is retired ? If SpaceX gets the Falcon 1 flying in the next year or so and can move on to Falcon 9, they'd have a sporting chance. Are there any chances of HTV flying by 2010 ? Maybe if launched on an Atlas 5 or Delta IV. Brian |
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MSNBC (JimO) on value of 'big door' on ISS
Brian Thorn wrote in
: On Sat, 08 Jul 2006 22:43:30 -0500, "Jorge R. Frank" wrote: Are there any chances of HTV flying by 2010 ? It depends on whether JAXA gets serious about developing the H-IIB. The H- IIA lacks the performance to carry an HTV to orbit. Weren't there stories a while ago about LockMart or Boeing license-building (or joint building) HTV as part of the COTS proposal? I remember the rumors, yes. But it appears that if they did propose that, they didn't make the first cut. -- JRF Reply-to address spam-proofed - to reply by E-mail, check "Organization" (I am not assimilated) and think one step ahead of IBM. |
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MSNBC (JimO) on value of 'big door' on ISS
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MSNBC (JimO) on value of 'big door' on ISS
In article ,
Brian Thorn wrote: That's what the shuttle *should* have done, instead of using the CBM interface only for the separate MPLMs. Why? There doesn't seem to be much room in the Shuttle's crew cabin for Station racks, which means they'd still have to use the MPLMs to haul them back and forth. For any substantial amount of cargo, you need to put a cargo carrier of some kind in the cargo bay. But it, the connecting tunnels, the docking assembly, etc., could all have been designed with the larger hatch from the start. In fact, if dim memory serves, that *was* the plan for SSF: there was to be no docking, only berthing(*), and the CBM was *the* interface. (* For those having trouble remembering the difference: with docking you slam into the station, preferably in a more-or-less controlled manner :-), while with berthing, you stop a few meters away, and the station arm grabs you and maneuvers you in, under positive control at whatever speed is convenient. ) In that case, why bother with the expense of a new Shuttle airlock, new shuttle docking tunnels, etc., when you can just berth the MPLM and move cargo directly? There's *some* advantage in moving a cargo module over to the station, because it permits loading and unloading to be done at leisure during normal station operations, instead of in a brief frenzy during a shuttle visit. But it's still sensible to use the big hatch in all new hardware, for the extra flexibility. Turn it around: given that at the beginning of the planning, there *was* no previous shuttle docking tunnel etc. -- the shuttle had never had an orbital destination that was pressurized -- why would you bother using anything but the big hatch? -- spsystems.net is temporarily off the air; | Henry Spencer mail to henry at zoo.utoronto.ca instead. | |
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MSNBC (JimO) on value of 'big door' on ISS
In article ,
Derek Lyons wrote: ...in production and fully operational by the time the shuttle is retired ? Several of them think they could do just that, if adequately and promptly funded. That's a common line in any business. Whether it accurately reflects reality is a matter open to question. True. On the other hand, there is nothing fundamentally unreasonable about it. Fund at least two of them well, with a healthy bonus for being first to meet certain milestones, and I think it's likely to come true. (If you fund only one, it's much iffier -- there's more incentive for him to just make excuses for running late instead of sweating to catch up, and more of a chance of picking the one who really was over-optimistic.) -- spsystems.net is temporarily off the air; | Henry Spencer mail to henry at zoo.utoronto.ca instead. | |
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MSNBC (JimO) on value of 'big door' on ISS
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MSNBC (JimO) on value of 'big door' on ISS
On Sun, 9 Jul 2006 19:06:13 -0500, Henry Spencer wrote
(in article ): In fact, if dim memory serves, that *was* the plan for SSF: there was to be no docking, only berthing(*), and the CBM was *the* interface. (* For those having trouble remembering the difference: with docking you slam into the station, preferably in a more-or-less controlled manner :-), while with berthing, you stop a few meters away, and the station arm grabs you and maneuvers you in, under positive control at whatever speed is convenient. ) SSF was baselined for CBMs between all pressurized station segments and two PMAs for orbiter docking from at least Phase B forward if not Phase A. So, as far back as at least 1990 there was no plan to use CBMs for physically connecting an orbiter to the station proper. Plans were ALWAYS to use PLMs (Pressurized Logistics Modules) and later MPLMs (originally denoting Mini-PLM) for bulk and outsized cargo transfer. -- Herb "Everything is controlled by a small evil group to which, unfortunately, no one we know belongs." ~Anonymous |
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MSNBC (JimO) on value of 'big door' on ISS
Herb Schaltegger wrote in
.com: As far as MSFC, Boeing and the rest of SSF Work Package 1 was concerned, there was never a design baseline involving a shuttle berthing to the SSF pressurized elements except for PMAs. Bulk cargo was always intended to be transfered via PLMs/MPLMs. On reflection I think you're correct - even back in the days when the shuttle was going to berth to SSF, they weren't going to use CBMs for the job. I also dimly recall the acronym wasn't always PMA; I thought it was Pressurized Berthing Adapter (PBA) at the beginning. Ah, found it, no longer on NASA Watch, but cached thanks to Google: http://www.google.com/search? q=cache:wBTnZc9pVlQJ:http://www.nasawatch.com/iss/12.02.9...nce.html+site: www.nasawatch.com+pressurized+berthing+adapter&hl= en&gl=us&ct=clnk&cd=1 (I also stand by my statements regarding APAS-89, regardless of what it was replacing...) -- JRF Reply-to address spam-proofed - to reply by E-mail, check "Organization" (I am not assimilated) and think one step ahead of IBM. |
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MSNBC (JimO) on value of 'big door' on ISS
"Jorge R. Frank" wrote in message ... And let us not forget why that changed: for the Shuttle-Mir program, NASA needed to adopt the Russian APAS-89 docking system. Once that was done, it was cheaper to just keep using that for ISS rather than the still- undeveloped SSF shuttle berthing interface. It looked like a good decision back when it looked like APAS-89 was going to become an ISS universal standard for Soyuz, Progress, and ATV as well. After the Russians abandoned APAS-89 and reverted to probe-and-drogue it looks markedly less so. So, the US was bitten because the Russians essentially made the same decision to drop a new system in favor for an older system due to cost. ;-) Jeff -- "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) |
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