Quote from: FinalFrontier on 07/21/2012 08:14 pmQuote from: Robotbeat on 07/21/2012 08:11 pmQuote from: FinalFrontier on 07/21/2012 08:08 pmQuote from: Robotbeat on 07/21/2012 08:03 pmQuote from: FinalFrontier on 07/21/2012 07:54 pmQuote from: dsmillman on 07/19/2012 03:46 pmEach Solar Array Wing (SAW) has been classified as an ORU. The question is how would we get a new SAW to ISS now. Can Dragon hold a SAW in its unpressurized section? It is likely that the P6 SAW's will have to be replaced if the ISS is to be operated through 2028. So what will be done?Two options.Launch on F9 v 1.1, use orbital bus based on dragon to get it to ISS.Or.Launch on Delta IV, use centaur common upper stage (which would be operating by then) as the orb bus, as it will be designed with more flexibility toward long duration missions in mind. Doubt one would fit in the dragon trunk, and if it did it would probably be too heavy. But flying one on an EELV class vehicle on its own with a simple orbital bus is no problem. Or unpressurized Cygnus.Antares have enough boost for that? A SAW is only like 2400 pounds. Should be good enough, at least the "enhanced" version.Are you including the truss array as well?It occurs to me that ultimately the "preferred" method of replacing these might be to simply build new truss segments for each one and replace all the gear in a modular fashion. Just disconnect umbilical and undock the four interlock pins. Might be easier then trying to replace individual components like the arrays themselves on the truss. That's why I was thinking it would probably be good to include quite a bit of margin weight wise. If you replace the whole truss:A) Where will you relocate the ELCs, EPs, and AMS?B) Center of gravity changes, as I recall when P3/P4 (or was it S3/S4) was being installed the CMGs started overloading as it was being moved from shuttle to install position. That is one reason why all of the Port trusses were not assembled all at once, instead they were assembled Starboard-Port-Starboard-Port et cetera. Spin-stablization is probably not a good option given the size and potential restrictions on power, fuel, CMGs, Arm use, et cetera, but I lack the details on such limits.C) Without a shuttle around, how will you stabilize the ISS while you swap the trusses out (inner trusses would be a major problem to swap out)?
Quote from: Robotbeat on 07/21/2012 08:11 pmQuote from: FinalFrontier on 07/21/2012 08:08 pmQuote from: Robotbeat on 07/21/2012 08:03 pmQuote from: FinalFrontier on 07/21/2012 07:54 pmQuote from: dsmillman on 07/19/2012 03:46 pmEach Solar Array Wing (SAW) has been classified as an ORU. The question is how would we get a new SAW to ISS now. Can Dragon hold a SAW in its unpressurized section? It is likely that the P6 SAW's will have to be replaced if the ISS is to be operated through 2028. So what will be done?Two options.Launch on F9 v 1.1, use orbital bus based on dragon to get it to ISS.Or.Launch on Delta IV, use centaur common upper stage (which would be operating by then) as the orb bus, as it will be designed with more flexibility toward long duration missions in mind. Doubt one would fit in the dragon trunk, and if it did it would probably be too heavy. But flying one on an EELV class vehicle on its own with a simple orbital bus is no problem. Or unpressurized Cygnus.Antares have enough boost for that? A SAW is only like 2400 pounds. Should be good enough, at least the "enhanced" version.Are you including the truss array as well?It occurs to me that ultimately the "preferred" method of replacing these might be to simply build new truss segments for each one and replace all the gear in a modular fashion. Just disconnect umbilical and undock the four interlock pins. Might be easier then trying to replace individual components like the arrays themselves on the truss. That's why I was thinking it would probably be good to include quite a bit of margin weight wise.
Quote from: FinalFrontier on 07/21/2012 08:08 pmQuote from: Robotbeat on 07/21/2012 08:03 pmQuote from: FinalFrontier on 07/21/2012 07:54 pmQuote from: dsmillman on 07/19/2012 03:46 pmEach Solar Array Wing (SAW) has been classified as an ORU. The question is how would we get a new SAW to ISS now. Can Dragon hold a SAW in its unpressurized section? It is likely that the P6 SAW's will have to be replaced if the ISS is to be operated through 2028. So what will be done?Two options.Launch on F9 v 1.1, use orbital bus based on dragon to get it to ISS.Or.Launch on Delta IV, use centaur common upper stage (which would be operating by then) as the orb bus, as it will be designed with more flexibility toward long duration missions in mind. Doubt one would fit in the dragon trunk, and if it did it would probably be too heavy. But flying one on an EELV class vehicle on its own with a simple orbital bus is no problem. Or unpressurized Cygnus.Antares have enough boost for that? A SAW is only like 2400 pounds. Should be good enough, at least the "enhanced" version.
Quote from: Robotbeat on 07/21/2012 08:03 pmQuote from: FinalFrontier on 07/21/2012 07:54 pmQuote from: dsmillman on 07/19/2012 03:46 pmEach Solar Array Wing (SAW) has been classified as an ORU. The question is how would we get a new SAW to ISS now. Can Dragon hold a SAW in its unpressurized section? It is likely that the P6 SAW's will have to be replaced if the ISS is to be operated through 2028. So what will be done?Two options.Launch on F9 v 1.1, use orbital bus based on dragon to get it to ISS.Or.Launch on Delta IV, use centaur common upper stage (which would be operating by then) as the orb bus, as it will be designed with more flexibility toward long duration missions in mind. Doubt one would fit in the dragon trunk, and if it did it would probably be too heavy. But flying one on an EELV class vehicle on its own with a simple orbital bus is no problem. Or unpressurized Cygnus.Antares have enough boost for that?
Quote from: FinalFrontier on 07/21/2012 07:54 pmQuote from: dsmillman on 07/19/2012 03:46 pmEach Solar Array Wing (SAW) has been classified as an ORU. The question is how would we get a new SAW to ISS now. Can Dragon hold a SAW in its unpressurized section? It is likely that the P6 SAW's will have to be replaced if the ISS is to be operated through 2028. So what will be done?Two options.Launch on F9 v 1.1, use orbital bus based on dragon to get it to ISS.Or.Launch on Delta IV, use centaur common upper stage (which would be operating by then) as the orb bus, as it will be designed with more flexibility toward long duration missions in mind. Doubt one would fit in the dragon trunk, and if it did it would probably be too heavy. But flying one on an EELV class vehicle on its own with a simple orbital bus is no problem. Or unpressurized Cygnus.
Quote from: dsmillman on 07/19/2012 03:46 pmEach Solar Array Wing (SAW) has been classified as an ORU. The question is how would we get a new SAW to ISS now. Can Dragon hold a SAW in its unpressurized section? It is likely that the P6 SAW's will have to be replaced if the ISS is to be operated through 2028. So what will be done?Two options.Launch on F9 v 1.1, use orbital bus based on dragon to get it to ISS.Or.Launch on Delta IV, use centaur common upper stage (which would be operating by then) as the orb bus, as it will be designed with more flexibility toward long duration missions in mind. Doubt one would fit in the dragon trunk, and if it did it would probably be too heavy. But flying one on an EELV class vehicle on its own with a simple orbital bus is no problem.
Each Solar Array Wing (SAW) has been classified as an ORU. The question is how would we get a new SAW to ISS now. Can Dragon hold a SAW in its unpressurized section? It is likely that the P6 SAW's will have to be replaced if the ISS is to be operated through 2028. So what will be done?
Quote from: Go4TLI on 07/20/2012 09:02 pmI recommend and endorse a nuclear reactorNo way. Too close to earth. If you must use a reactor in space put it high enough that it won't return in a few years without rebost.
I recommend and endorse a nuclear reactor
Quote from: pathfinder_01 on 07/20/2012 11:04 pmQuote from: Go4TLI on 07/20/2012 09:02 pmI recommend and endorse a nuclear reactorNo way. Too close to earth. If you must use a reactor in space put it high enough that it won't return in a few years without rebost. Ahh, thank you. While I was very much joking with my response this kind of statement goes a long way as to why we are at times limited in our capabilities.
There is no reason to replace the trusses
Good post OldAtlas_Eguy maybe you can address these questions.What about mico meteorite damage to the panels? Is there an on going review of the condition of the panels?
The major concern about power is the batteries which have a average life of just 6.5 years. There are 4 sets of 38 batteries with each battery weighing 375lb. It would take 2 Dragon flights complete external weight capability to do a single battery set replacement.
Quote from: oldAtlas_Eguy on 07/22/2012 05:12 pmThe major concern about power is the batteries which have a average life of just 6.5 years. There are 4 sets of 38 batteries with each battery weighing 375lb. It would take 2 Dragon flights complete external weight capability to do a single battery set replacement.Isn't it 48 battery ORUs total, with each ORU weighing ~375lb? (24 battery sets, each consisting of 2 battery ORUs. Each ORU contains 38 individual Ni/H2 cells, each of which is relatively small and light.)
24 BCDU's each weighing 100kg. The earlier 38 value is for the individual cells in a BCDU.
Average battery life for who? Most all forms of batteries can go for 15 years or more at 90% original capacity if someone with the brains of a lemur controls their operation.
Why fixate on trading services?
Quote from: Jim on 07/22/2012 07:27 pmWhy fixate on trading services? surprised, you should be smart enough for this. The ATV SM for Orion should have been killed a year ago. http://forum.nasaspaceflight.com/index.php?topic=27029.390