Incidentally, regarding repairing the hole; assuming there's not significant damage belowdecks, wouldn't slapping a bit over-sized steel plate atop the hole (It'd protrude above deck level, but only by its thickness) and welding it in place be good enough? Especially if there are time constraints?
Quote from: CJ on 03/10/2016 01:27 amIncidentally, regarding repairing the hole; assuming there's not significant damage belowdecks, wouldn't slapping a bit over-sized steel plate atop the hole (It'd protrude above deck level, but only by its thickness) and welding it in place be good enough? Especially if there are time constraints? I expect that depends on what the lease agreement says. Informed speculation holds that these are leased vessels, not purchased, and that they will someday perhaps be returned. It may say that they have to be repaired before returning, or repaired whenever damage happens (in case the return happens early, eto) so a patch like that might be OK for a while, or might be OK forever, or might not be OK at all.
Thread 3 for the ASDS Fleet.Thread 1:http://forum.nasaspaceflight.com/index.php?topic=36140.0Thread 2:http://forum.nasaspaceflight.com/index.php?topic=36326.0
I've been giving some thought to the hole in the deck. I'm not worried it holed the hill bottom too, because the ASDS was most likely ballasted (so there would have been water between the deck and hull bottom).
However... We've seen what LOX and RP1 do when they combine during other hard landings. Now, imagine that happening INSIDE the hull. I hope it didn't.
edit: note that it was Kabloona that started the initial thread and he's been active thorough all of this. A fact that Elon recognized when he named the phenomenon that happens when a rocket falls over as "kaboom".
Quote from: Lar on 03/10/2016 01:31 amQuote from: CJ on 03/10/2016 01:27 amIncidentally, regarding repairing the hole; assuming there's not significant damage belowdecks, wouldn't slapping a bit over-sized steel plate atop the hole (It'd protrude above deck level, but only by its thickness) and welding it in place be good enough? Especially if there are time constraints? I expect that depends on what the lease agreement says. Informed speculation holds that these are leased vessels, not purchased, and that they will someday perhaps be returned. It may say that they have to be repaired before returning, or repaired whenever damage happens (in case the return happens early, eto) so a patch like that might be OK for a while, or might be OK forever, or might not be OK at all.Also kinda depends on when they'll need OCISLY to sail again, in terms of how quick-and-dirty the fix has to be. As I just inquired in the CSR-8 discussion thread, if they try an RTLS on that flight, we may not have a need for OCISLY for a couple of months or more.
Elon Musk @elonmuskRocket landed hard on the droneship. Didn't expect this one to work (v hot reentry), but next flight has a good chance.
Falcon 9 uses an open hydraulic system that has a separate tank of RP-1 (which is used as the hydraulic fluid) pressurized by Nitrogen near the interstage, which, after use, drains down back into the main RP-1 tank for "reuse" by the engines. There are a variety of reasons that SpaceX made decisions to use this design:
I believe a skilled welder could have the deck in like new condition in a day or two. Replacing the damaged equipment will take longer.
Quote from: CJ on 03/10/2016 01:27 amIncidentally, regarding repairing the hole; assuming there's not significant damage belowdecks, wouldn't slapping a bit over-sized steel plate atop the hole (It'd protrude above deck level, but only by its thickness) and welding it in place be good enough? Especially if there are time constraints? I expect that depends on what the lease agreement says. Informed speculation holds that these are leased vessels, not purchased, and that they will someday perhaps be returned. The agreement may say that significant damages have to be repaired before returning, or repaired whenever damage happens (in case the return happens early, etc.) so a patch like that might be OK for a while, or might be OK forever, or might not be OK at all because they want a real repair with replacement at the normal seams, not patching....
Quote from: CJ on 03/10/2016 01:27 amHowever... We've seen what LOX and RP1 do when they combine during other hard landings. Now, imagine that happening INSIDE the hull. I hope it didn't. Well, there's no evidence from the photo that it did. One would also assume the ballast water to be relatively RP1-free, otherwise they wouldn't be pumping it over the side..
Quote from: Wolfram66 on 03/10/2016 02:58 amFalcon 9 uses an open hydraulic system that has a separate tank of RP-1 (which is used as the hydraulic fluid) pressurized by Nitrogen near the interstage, which, after use, drains down back into the main RP-1 tank for "reuse" by the engines. There are a variety of reasons that SpaceX made decisions to use this design:I don't think its been established that the hydraulic fluid being used is fuel. I don't think its been established that the expended fluid goes into the main fuel tank. These have been speculated as likely and seem so but I don't think its been proven. Or am I wrong?
Quote from: Lar on 03/10/2016 01:31 amQuote from: CJ on 03/10/2016 01:27 amIncidentally, regarding repairing the hole; assuming there's not significant damage belowdecks, wouldn't slapping a bit over-sized steel plate atop the hole (It'd protrude above deck level, but only by its thickness) and welding it in place be good enough? Especially if there are time constraints? I expect that depends on what the lease agreement says. Informed speculation holds that these are leased vessels, not purchased, and that they will someday perhaps be returned. The agreement may say that significant damages have to be repaired before returning, or repaired whenever damage happens (in case the return happens early, etc.) so a patch like that might be OK for a while, or might be OK forever, or might not be OK at all because they want a real repair with replacement at the normal seams, not patching....I've never dealt with a maritime lease, but I've dealt with all sorts of commercial building leases. *IF* there's a similarity, a temporary repair would be okay for a while under most, especially if it's needed to avoid any downtime. The caveats would be that the temp repair does not risk further damage, and meets codes. On the other hand, most commercial building owners would not be okay with the lessee firing enormous rockets at it.
Quote from: CameronD on 03/10/2016 01:35 amQuote from: CJ on 03/10/2016 01:27 amHowever... We've seen what LOX and RP1 do when they combine during other hard landings. Now, imagine that happening INSIDE the hull. I hope it didn't. Well, there's no evidence from the photo that it did. One would also assume the ballast water to be relatively RP1-free, otherwise they wouldn't be pumping it over the side.. Good point; pumping water over the side is indeed a pretty clear indication of no contamination. You also raised an excellent point regarding stratifying inspectors when it comes to fixing the hole. I darkly suspect that'll take much longer than the actual repairs.
Quote from: OxCartMark on 03/10/2016 03:15 amQuote from: Wolfram66 on 03/10/2016 02:58 amFalcon 9 uses an open hydraulic system that has a separate tank of RP-1 (which is used as the hydraulic fluid) pressurized by Nitrogen near the interstage, which, after use, drains down back into the main RP-1 tank for "reuse" by the engines. There are a variety of reasons that SpaceX made decisions to use this design:I don't think its been established that the hydraulic fluid being used is fuel. I don't think its been established that the expended fluid goes into the main fuel tank. These have been speculated as likely and seem so but I don't think its been proven. Or am I wrong?Wolfram66 is stating all this as facts.Either its complete and detailed speculation without any statement to that effect ...or Wolfram66 is in a position to know and to discuss it in a public thread.I certainly hope it's the latter as this is precisely the kind of details I want to learn about and understand.PS If SpaceX is using fuel that gets dumped into the fuel tank, why wouldn't they pressurized with Helium?There is a large supply of He and it's the gas already being used to pressurize the fuel.Is it because they need an even higher pressure, because the hydraulic actuators would be powered by the differential pressure, and the fuel tank drain is itself pressurized?
I doubt you'd use RP-1 if you're using a separate reservoir.
Falcon 9 uses an open hydraulic system that has a separate tank of RP-1 (which is used as the hydraulic fluid) pressurized by Nitrogen near the interstage, which, after use, drains down back into the main RP-1 tank for "reuse" by the engines.
...Incidentally, regarding repairing the hole; assuming there's not significant damage belowdecks, wouldn't slapping a bit over-sized steel plate atop the hole (It'd protrude above deck level, but only by its thickness) and welding it in place be good enough? Especially if there are time constraints?