When it comes to Dragon 2 and its snazzy large-sized touchscreens -- how are these things able to stand up against the vibrations, shocks and stresses of space launch and re-entry? I'd imagine that such large thin screens (tablets?) would be particularly vulnerable to such forces.Are these primary control/viewing interfaces backed up by some kind of simpler and more rugged backup control scheme if they fail? Are these touchscreens the most modern choices available? Or could they one day give way to Augmented Reality (AR) projections on a spacesuit helmet visor?
Quote from: matthewkantar on 08/18/2018 07:16 pmQuote from: Roy_H on 08/18/2018 07:07 pmI don't see why the helium would be at ambient. I would expect it to be supper chilled, possibly below the LOX temperature and "warm up" to the LOX temp as it is being loaded.Do you not remember the Amos-6 F-9 exploding, destroying the pad, during a static fire? The cause is thought to be densified LOX, in the weave of the COPV, near its solidification point being frozen by colder Helium inside the COPV.MatthewIt was a little bit more complex. LOX permeated the carbon fiber overwrap and filled cavities caused by buckles in the liner. Than two things happened: the supercooled helium caused the LOX close to the liner to freeze and the growing pressure inside the helium bottles caused the liner to expand. The frozen oxygen could not escape the same way it got in and instead got pressed against the overwrap. That was either enough to ignite the overwrap or it caused some fibres to rip which triggered the ignition.By pressurizing the COPVs before they are submerged in LOX, they won't expand when the LOX gets loaded.
Quote from: Roy_H on 08/18/2018 07:07 pmI don't see why the helium would be at ambient. I would expect it to be supper chilled, possibly below the LOX temperature and "warm up" to the LOX temp as it is being loaded.Do you not remember the Amos-6 F-9 exploding, destroying the pad, during a static fire? The cause is thought to be densified LOX, in the weave of the COPV, near its solidification point being frozen by colder Helium inside the COPV.Matthew
I don't see why the helium would be at ambient. I would expect it to be supper chilled, possibly below the LOX temperature and "warm up" to the LOX temp as it is being loaded.
Back to Helium preloading ...Quote from: jpo234 on 08/18/2018 11:49 pm...Following the AMOS-6 loss, weren't the propellant loading procedures changed (taking longer) to mitigate the issue until a new COPV was fielded? And about the time of the first Block 5 flight, weren't the propellant loading times shortened, suggesting use of the new COPV design, and surprising everyone when it was revealed that the new COPV wouldn't fly until DM1?Is it possible that those quicker loading times were a result of implementing the Helium preloading procedure, where the COPVs are precharged to full pressure with ambient temperature Helium, and then topped off (filled the remaining 80% of the way) at constant pressure as the COPVs were chilled during LOX load?
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Quote from: Rondaz on 08/18/2018 06:40 amCOPVs, will be loaded with helium and verified to be in a stable configuration prior to astronaut arrival at the launch pad. The astronauts then will board the spacecraft about two hours before launchQuote from: Rondaz on 08/18/2018 06:40 amThis timeline is consistent with the fueling procedures SpaceX uses for its commercial resupply missions and satellite launches.COPVs being loaded with helium more than 2 hours before launch is new isn't it?
COPVs, will be loaded with helium and verified to be in a stable configuration prior to astronaut arrival at the launch pad. The astronauts then will board the spacecraft about two hours before launch
This timeline is consistent with the fueling procedures SpaceX uses for its commercial resupply missions and satellite launches.
SpaceX gears up for Crew Dragon’s first recovery with a giant inflatable cushionBy Eric RalphPosted on August 19, 2018Paired with observations and comments from sources familiar with the company, all signs seem to indicate that SpaceX is planning to recover their first Crew Dragon spacecraft with a giant inflatable cushion, to be towed a hundred or so miles off the coast of California by one of the company’s Port of LA-stationed recovery vessels.
Another fine product from the nonsense factory.
Quote from: nacnud on 08/20/2018 08:57 amAnother fine product from the nonsense factory. It's not quite ridiculous...
Quote from: clongton on 08/19/2018 02:39 pmQuote from: sanman on 08/19/2018 02:53 amIs there any scope for Augmented Reality micro-projection onto the Spacesuit helmet visor? This technology seems to be coming into availability for the consumer market, so why couldn't such a concept be useful for space applications as well?Augmented Reality micro-projection onto the helmet visor is not going to happen. It's unnecessarily complex, prohibitively expensive, inefficient for what is needed, and a waste of time because the suit is only worn during ascent and descent. During those periods the crew may as well be asleep for all the good that would do because the spacecraft is totally automated - which means that no human intervention is ever required - ever. Every possible contingency that in the past would have required a crewmember to do something is now handled by triple-redundant computer control faster than the ability of a human to even think. By the time any crew member even realized that there was some action needed the avionics package would have already identified the problem, analysed all possible reactions, made the appropriate selection and executed the command. The only thing a human being could do after that would be to screw it up. There is nothing - nothing - that visor displays could add to that. Truth be known the only real detail the crew actually needs to know is that the computer is on and functioning. Other than that, relax and enjoy the ride.rah rah but no...really noall that is kind of accurate as long as well the script is followed..when it doesnt...well they had a Dragon that required a lot of human intervention to stop from being space junk.it will happen again...
Quote from: sanman on 08/19/2018 02:53 amIs there any scope for Augmented Reality micro-projection onto the Spacesuit helmet visor? This technology seems to be coming into availability for the consumer market, so why couldn't such a concept be useful for space applications as well?Augmented Reality micro-projection onto the helmet visor is not going to happen. It's unnecessarily complex, prohibitively expensive, inefficient for what is needed, and a waste of time because the suit is only worn during ascent and descent. During those periods the crew may as well be asleep for all the good that would do because the spacecraft is totally automated - which means that no human intervention is ever required - ever. Every possible contingency that in the past would have required a crewmember to do something is now handled by triple-redundant computer control faster than the ability of a human to even think. By the time any crew member even realized that there was some action needed the avionics package would have already identified the problem, analysed all possible reactions, made the appropriate selection and executed the command. The only thing a human being could do after that would be to screw it up. There is nothing - nothing - that visor displays could add to that. Truth be known the only real detail the crew actually needs to know is that the computer is on and functioning. Other than that, relax and enjoy the ride.
Is there any scope for Augmented Reality micro-projection onto the Spacesuit helmet visor? This technology seems to be coming into availability for the consumer market, so why couldn't such a concept be useful for space applications as well?
I contend that if there is any chance of missing a Dragon 2 returning from an operational mission, then NASA will want to see how well the DM1 capsule performs splashing down following reentry. Yes, they've done splashdown and recovery tests with capsule mock-ups, but that's not the same as testing the performance of a just reentered production capsule.Color me skeptical.
I think it more likely that it is for fairing drop tests.