I believe that a "batteries and gyros" commercial mission to HST would be the most cost effective approach to maintaining our optical capability.
Not with the dragon. It is ill-suited for such a task.
Quote from: Jim on 09/24/2012 06:37 pmNot with the dragon. It is ill-suited for such a task. Why?
Quote from: Arb on 09/24/2012 06:41 pmQuote from: Jim on 09/24/2012 06:37 pmNot with the dragon. It is ill-suited for such a task. Why?It is not made to handle EVA's
Quote from: jongoff on 09/24/2012 10:19 pmQuote from: Jim on 09/24/2012 07:43 pmQuote from: Arb on 09/24/2012 06:41 pmQuote from: Jim on 09/24/2012 06:37 pmNot with the dragon. It is ill-suited for such a task. Why?It is not made to handle EVA'sOf the EVA related capabilities that Dragon lacks, which do you think are the biggest deals? Some sort of airlock? An RMS? Handholds of some sort? or something else? Just curious, because I know some companies trying to solve some of those issues....~JonWell, either they need an airlock, or the avionics (and everything else in the cabin) need to be vacuum-rated.If they have an RMS, they can mitigate the need for handholds on the Dragon capsule by putting the EVA crew in RMS foot restraints. Handholds on the trunk would still be a good idea, I think.
Quote from: Jim on 09/24/2012 07:43 pmQuote from: Arb on 09/24/2012 06:41 pmQuote from: Jim on 09/24/2012 06:37 pmNot with the dragon. It is ill-suited for such a task. Why?It is not made to handle EVA'sOf the EVA related capabilities that Dragon lacks, which do you think are the biggest deals? Some sort of airlock? An RMS? Handholds of some sort? or something else? Just curious, because I know some companies trying to solve some of those issues....~Jon
It's not the orbit that will decay on Hubble first; it's the gyros. Hubble uses CMGs exclusively for pointing, and they are in theory triple-redundant. However, they already have lost one since the last servicing...And extented missions can mean different things. At the moment Hubble is fully funded to provide a lot of support to the astronomers who use it (including 50% of my time). It's not impossible that this will go away in the future, much like it already has for Kepler. If that happens, the desire in the community for a new UV/Optical telescope will be considerably louder.As far as replacement, NASA is exploring the option of launching one of the two donated NRO sats as a UV/Optical successor to Hubble (with the other as WFIRST). It's all very nebulous at the moment, but some recent (two weeks ago) talks on the subject are here: http://www.princeton.edu/astro/news-events/public-events/new-telescope-meeting/program/NEW-Telescope-Meeting-Sept-2012-Program.pdf The presentaions from Gehrels, Kruk, and Scowen are especially relevant. Note that Kruk brings up the idea of putting NRO/WFIRST at GSO (rather than SEL2) to allow servicing.
Quote from: Jorge on 09/24/2012 11:03 pmQuote from: jongoff on 09/24/2012 10:19 pmQuote from: Jim on 09/24/2012 07:43 pmQuote from: Arb on 09/24/2012 06:41 pmQuote from: Jim on 09/24/2012 06:37 pmNot with the dragon. It is ill-suited for such a task. Why?It is not made to handle EVA'sOf the EVA related capabilities that Dragon lacks, which do you think are the biggest deals? Some sort of airlock? An RMS? Handholds of some sort? or something else? Just curious, because I know some companies trying to solve some of those issues....~JonWell, either they need an airlock, or the avionics (and everything else in the cabin) need to be vacuum-rated.If they have an RMS, they can mitigate the need for handholds on the Dragon capsule by putting the EVA crew in RMS foot restraints. Handholds on the trunk would still be a good idea, I think.This is all true.The question is whether these capabilities would cost more than alternates, including building a new HST or some sort of robotic repair mission.
As I noted above, build a new one on the existing spec's. If the f9 can't handle it, then the FH will likely be on line by then. Currently there's no way of doing an EVA mission to the existing HST.Some of you seem hung up on a refurbishment mission whilst ignoring all the practical issues.Perhaps if you're so keen on it, you could work up a funding model along the following lines:Base HST escalate to today's dollars assuming no specification changes.LV costIntegration, handling, support, etc, costsTotal Cost of new unit versus- well, how much do you suppose a full up refurbishment mission will cost since we have no vehicle currently capable of undertaking it?
Quote from: beancounter on 09/25/2012 01:21 amAs I noted above, build a new one on the existing spec's. If the f9 can't handle it, then the FH will likely be on line by then. Currently there's no way of doing an EVA mission to the existing HST.Some of you seem hung up on a refurbishment mission whilst ignoring all the practical issues.Perhaps if you're so keen on it, you could work up a funding model along the following lines:Base HST escalate to today's dollars assuming no specification changes.LV costIntegration, handling, support, etc, costsTotal Cost of new unit versus- well, how much do you suppose a full up refurbishment mission will cost since we have no vehicle currently capable of undertaking it?The problem which I have learned on this site, is that the original suppliers likely no longer exist, or no parts are no longer available, which means re-design & re-certification (likely).One problem I thought of, of my thoughts on refurbishment, is that the SpaceX document (but it wouldn't matter which vehicle) shows a robotic arm for instrument replacement. That's fine, but you have to get those doors opened first, and then you have to close them; remember the fun they once had on an EVA? A manned EVA might be the better bet (still).
I guess a lot depends on how expensive a crew flight with Dragon actually ends up being. If it's closer to their current $130M for a cargo flight, then it could very well be possible to have some sort of an airlock module that you could bring up on the trunk,
Quote from: jongoff on 09/25/2012 12:16 amI guess a lot depends on how expensive a crew flight with Dragon actually ends up being. If it's closer to their current $130M for a cargo flight, then it could very well be possible to have some sort of an airlock module that you could bring up on the trunk, Herein lies the rub.An "airlock module" would have to mate with the Dragon via the nose docking adapter (as opposed to somehow attaching to the side hatch), and the nose docking adapter would be occupied by the Hubble docking system. The only way around this would be to stow the airlock module in the Dragon trunk, and then somehow re-position it to the front of Dragon, where it would then serve as the interface between Dragon and HST. The RMS required for all those maneuvers would be extremely expensive to develop.It would be much cheaper to vacuum-rate the Dragon interior avionics.
It would be much cheaper to vacuum-rate the Dragon interior avionics.
Herein lies the rub.An "airlock module" would have to mate with the Dragon via the nose docking adapter (as opposed to somehow attaching to the side hatch), and the nose docking adapter would be occupied by the Hubble docking system. The only way around this would be to stow the airlock module in the Dragon trunk, and then somehow re-position it to the front of Dragon, where it would then serve as the interface between Dragon and HST.
The RMS required for all those maneuvers would be extremely expensive to develop.It would be much cheaper to vacuum-rate the Dragon interior avionics.
Or put a hatch in the heat shield.PICA-X is a seamed ablative anyway... and that's assuming you actually want to throw away your airlock before reentry.. otherwise just add an egress hatch to the side of the Dragon and make the airlock internal.