The delta-V, cargo mass, structural strain and control authority of such a tug would need investigating.
How big is the VASIMR engine? How big is the biggest ISS airlock?
Are some of the ISS crew members going to be trained in the skills needed to properly take apart the VASIMR engine?Are any of the labs properly equiped to deal with the potential environmental and other issues of taking apart the VASIMR engine in zero G?Where is the Internet reference that answers these types of questions about the VASIMR engine?
I'm glad to know that Cog_in_the_machine has the answers equal to his or her sarcasm. I always have questions.Cheers!
...if Shuttle becomes unavailable because of some accident or system failure, that is not a violation of US law. But if NASA shuts down STS before its crew-capable replacement is available, that is a violation of US law. That has yet to be addressed, at least as far as I am aware.
Quote from: MP99 on 08/23/2010 12:01 pmBTW, 51D - what is now covered by the "21st Century Spaceport" programme? I'd understood it was partly to setup infrastructure for commercial launchers, including a commercial HLV. Without a commercial HLV, what is that element of the budget expected to accomplish under the Senate's bill?cheers, MartinI would suggest that *that* part of the budget could be redirected to help offset the cost of 2xShuttle flights per year.
BTW, 51D - what is now covered by the "21st Century Spaceport" programme? I'd understood it was partly to setup infrastructure for commercial launchers, including a commercial HLV. Without a commercial HLV, what is that element of the budget expected to accomplish under the Senate's bill?cheers, Martin
from a dispassionate technical perspective those dreams look unrealistic.
Quote from: A_M_Swallow on 08/23/2010 05:46 pmThe delta-V, cargo mass, structural strain and control authority of such a tug would need investigating.I suspect all-axis translation would be a problem.
If Orion can provide "last mile" guidance and ISS docking for that cargo, up mass logistics problem would appear solved, rather nicely in fact.
Also, interesting comment at http://www.spacenews.com/civil/100820-nasa-ease-doubts-commercial-crew-support.html, that commercial launches would need to reimburse NASA for the cost of any NASA facilities used. Wouldn't that make it less likely they'd want to take advantage of the "21st Century" infrastructure?I can understand refurb'ing SLS-relevant infrastructure during the gap, when it will have minimal impact. For anything commercial, I'd have thought the operators might be happy to invest themselves, then recover the costs through launch services over some guaranteed number of launches? << To be honest, that's more of a question than a statement.cheers, Martin
Here's a wild idea: Has anyone ever looked into adding some kind of additional "workshop" module to ISS to support full utilization? It could be used for maintenance and tinkering with various experiments on-board (people have been asking about VaSIMR). Or, if it's got enough room, failed components could be investigated there in lieu of downmass opportunities. Of course, if those things couldn't squeeze into Dragon for a ride home that means it would have to be quite spacious itself, perhaps an inflatable with an oversized airlock?Long ago our space station was envisioned as an orbital assembly station. This could be a cool way to take one step in that direction. Maybe even have some on-orbit manufacturing and assembly experiments.
Quote from: clongton on 08/23/2010 12:21 pmQuote from: MP99 on 08/23/2010 12:01 pmBTW, 51D - what is now covered by the "21st Century Spaceport" programme? I'd understood it was partly to setup infrastructure for commercial launchers, including a commercial HLV. Without a commercial HLV, what is that element of the budget expected to accomplish under the Senate's bill?cheers, MartinI would suggest that *that* part of the budget could be redirected to help offset the cost of 2xShuttle flights per year.That was what I was edging towards, but to me this is by far the element of the bills that I least understand.Also, interesting comment at http://www.spacenews.com/civil/100820-nasa-ease-doubts-commercial-crew-support.html, that commercial launches would need to reimburse NASA for the cost of any NASA facilities used. Wouldn't that make it less likely they'd want to take advantage of the "21st Century" infrastructure?I can understand refurb'ing SLS-relevant infrastructure during the gap, when it will have minimal impact. For anything commercial, I'd have thought the operators might be happy to invest themselves, then recover the costs through launch services over some guaranteed number of launches? << To be honest, that's more of a question than a statement.cheers, Martin
Here's a wild idea: Has anyone ever looked into adding some kind of additional "workshop" module to ISS to support full utilization? It could be used for maintenance and tinkering with various experiments on-board (people have been asking about VaSIMR). Or, if it's got enough room, failed components could be investigated there in lieu of downmass opportunities. Of course, if those things couldn't squeeze into Dragon for a ride home that means it would have to be quite spacious itself, perhaps an inflatable with an oversized airlock?
Starting up new Shuttle production now would be ... the opposite of game-changing!
Also, interesting comment at http://www.spacenews.com/civil/100820-nasa-ease-doubts-commercial-crew-support.html
NASA officials had little to say about the thorny issue of indemnification, or shielding commercial launch service providers against catastrophic third-party liability claims.
Quote from: sdsdsfrom a dispassionate technical perspective those dreams look unrealistic.lol.... Yeah what the world needs now is a few hypergolic depots instead of the Space Shuttle!
...Long ago our space station was envisioned as an orbital assembly station...
Here we get this FY2011 announcement of a 21st Century launch complex, but when I read that NASA is expecting the commercial companies to come back to them with their needs, it makes it seem that it was just pork.
No viable. a. Astronauts are not real techniciansb. Spacecraft are full of bad propellants and pyros.c. Not enough air to waste in airlocks that larged. No spacecraft in the vicinity of the ISS
1. They are quite amenable and able to be trained for assembling large items in space, with the assitance of Canadarms and Robonauts built for the purpose.ii. This has not stopped the current work at all.c. If we're gonna work in space, we'll have to bring up sufficient O2, no matter what the future holds.IV. To quote Jed Clampett: "Every time we hear that bell, someone's at the door!" Every time the shuttle, a type of spacecraft, gets in the vicinity of the ISS, crew members ring the doorbell!
Quote from: MP99 on 08/23/2010 11:45 pmAlso, interesting comment at http://www.spacenews.com/civil/100820-nasa-ease-doubts-commercial-crew-support.html, that commercial launches would need to reimburse NASA for the cost of any NASA facilities used. Wouldn't that make it less likely they'd want to take advantage of the "21st Century" infrastructure?I can understand refurb'ing SLS-relevant infrastructure during the gap, when it will have minimal impact. For anything commercial, I'd have thought the operators might be happy to invest themselves, then recover the costs through launch services over some guaranteed number of launches? << To be honest, that's more of a question than a statement.cheers, MartinIf you watch the webcast, they meant that commercial companies could use NASA testing facilities, etc. But it wouldn't be free. They weren't talking about the launch pad and service tower costs. But if investments are made on LC-40, I imagine that the rent charged to SpaceX could also be increased. That's a good question.
It's quite interesting to read that some spaceflight supporters in Washington D.C. are still keeping alive the dream of a substantial extension to the Shuttle program! It seems this is now principally motivated by a desire to fully support ISS.While that kind of thinking may be politically viable, from a dispassionate technical perspective those dreams look unrealistic. Instead the reality seems to be that decisions made long ago have left ISS in a posture where its continuation is exposed to some risks, and no amount of funding now can mitigate those risks in a timely fashion.
Much is made of ISS dependence on Soyuz for crew rotation. Stand-down of Soyuz would put continued station operation at risk; it might also put crew safety at risk. However, the likelihood of a Soyuz stand-down is small, and the plan for retiring that risk is the development of commercial crew taxis.
Much is made of ISS dependence on Progress, HTV, ATV, and COTS for up-mass. None of these have the capability to carry certain large items (solar array blankets, rotary joint race rings, etc.) Losing the use of an item like that on orbit would curtail full use of ISS. However the risk of such a loss is low, the result of such a loss may be tolerable, and the eventual plan for retiring that risk is the development of SLS and a ISS-capable tug.
Much is made of ISS dependence on COTS for down-mass. The only COTS vehicle planned to provide any down-mass is Dragon, and Dragon cannot transport certain large items (ammonia pumps, for example). Bringing this type of failed component down for analysis would be helpful. However, full utilization of ISS does not require that large items be transported down; this capability would be an expensive convenience.
Even so, why is it difficult to extend Shuttle? The technical reasons commonly mentioned are: no available SRB components and a cold SRB production line; no available ET foam, and a nearly-cold ET production line; orbiters requiring maintenance with limited parts availability; crawler and crawler-way degradation and other deferred ground support maintenance. The non-technical reasons commonly mentioned are: no support from the Executive branch; strong resistance based on safety concerns from ASAP; uncertain Legislative support for funding; uncertain support from the general populace; uncertain support from other parts of NASA.
Commercial crew; Orion; LEO SLS; ISS-capable tug. This is where NASA is headed. Starting up new Shuttle production now would be ... the opposite of game-changing!