Quote from: mme on 12/05/2018 07:04 pmI would wait for a real analysis of the first stage that will hence forth be named "Bob."I like that name.Personally, I don't see this stage flying again regardless of what Musk says, at least not as a whole unit. Maybe the tankage and interstage could be reused, but the rest will probably be scrapped and tested to see the effects of salt-water corrosion on flown hardware.
I would wait for a real analysis of the first stage that will hence forth be named "Bob."
So how long until they ask about the landing at the post launch press conference?(Drinking game, take a shot everytime they ask about it)
There she blows..
Quote from: StuffOfInterest on 12/05/2018 06:57 pmQuote from: ugordan on 12/05/2018 06:36 pmQuote from: StuffOfInterest on 12/05/2018 06:33 pmI wonder if the control software could be modified so that when a fin freezes the fin on the opposite side can be placed in a position to dampen the action of the first one and then let the two other grids fins do all the work? There wouldn't be as much control but if it can avoid a roll then there may be enough to get the booster down.How do you propose to do that if all the fins are powered by the single pump?Ouch. I thought originally it was independent pumps but I guess it is one pump driving all four actuators. Definitely nothing that can be done there without a redundant string.Except for ejecting/blasting off all the grid fins. Which, of course introduce new failure modes nobody needs.
Quote from: ugordan on 12/05/2018 06:36 pmQuote from: StuffOfInterest on 12/05/2018 06:33 pmI wonder if the control software could be modified so that when a fin freezes the fin on the opposite side can be placed in a position to dampen the action of the first one and then let the two other grids fins do all the work? There wouldn't be as much control but if it can avoid a roll then there may be enough to get the booster down.How do you propose to do that if all the fins are powered by the single pump?Ouch. I thought originally it was independent pumps but I guess it is one pump driving all four actuators. Definitely nothing that can be done there without a redundant string.
Quote from: StuffOfInterest on 12/05/2018 06:33 pmI wonder if the control software could be modified so that when a fin freezes the fin on the opposite side can be placed in a position to dampen the action of the first one and then let the two other grids fins do all the work? There wouldn't be as much control but if it can avoid a roll then there may be enough to get the booster down.How do you propose to do that if all the fins are powered by the single pump?
I wonder if the control software could be modified so that when a fin freezes the fin on the opposite side can be placed in a position to dampen the action of the first one and then let the two other grids fins do all the work? There wouldn't be as much control but if it can avoid a roll then there may be enough to get the booster down.
The grid fins will flay again, since they are extremely expensive and it takes forever to make them IIRC.
Quote from: Oersted on 12/05/2018 07:04 pmIf a stuck grid fin caused the roll I would say that the slowdown in speed had more to do with stopping the roll than any transfer of momentum from the leg deployment. At slow speed the reaction control thrusters could counteract the aerodynamic forces.Nope. With the legs extended the "wider momentum" makes it much harder for the RCS fins to affect roll. This is another reason why the legs are deployed at the last second. Sure, lower speed helps in that it makes the stuck grid fins less effective, but note the timing of the leg deploy and the slowdown of the roll. It's all from the legs.
If a stuck grid fin caused the roll I would say that the slowdown in speed had more to do with stopping the roll than any transfer of momentum from the leg deployment. At slow speed the reaction control thrusters could counteract the aerodynamic forces.
Quote from: Ronsmytheiii on 12/05/2018 07:13 pmSo how long until they ask about the landing at the post launch press conference?(Drinking game, take a shot everytime they ask about it)First question, guaranteed...
Quote from: kevinof on 12/05/2018 07:00 pmThere she blows..Wow! Can a large enough ship get in that close to shore to recover the booster?
Any chance of a successful landing had the ditch order not been given? Landing looks close to nominal. Yes, on the the Ocean but still.....
Quote from: edzieba on 12/05/2018 06:45 pmDoes Falcon still have independent gas-generator nozzle actuation for the centre Merlin, or was that dumped in the move to the octaweb?Dumped, on the first stage it was only ever available on the Falcon 1.
Does Falcon still have independent gas-generator nozzle actuation for the centre Merlin, or was that dumped in the move to the octaweb?
Go quest just left port from the info on the Port Canaveral ship tracker.
I would wonder if the engineers might talk Musk out of adding a redundant pump if they can just make the one more robust. I seems like understanding and fixing the issue is better than redundancy for a non-mission critical system.
Quote from: DanielW on 12/05/2018 06:51 pmI would wonder if the engineers might talk Musk out of adding a redundant pump if they can just make the one more robust. I seems like understanding and fixing the issue is better than redundancy for a non-mission critical system.I wouldn't take any of Elon's tweets about the stage too seriously just yet.The stage just landed, they didn't even look at it, nobody had time to fully analyze anything yet.These are off the cuff responses, actual decisions will happen after thorough analysis and time to think.As a general rule, don't take his tweets too seriously, especially when he's tweeting so close to the event that he obviously did not have the time to fully think it thru.edit: fix typo
At what point when you don't have complete control of your rocket flying back toward land does range safety kick in? While i'm sure they are happy they got their rocket back (albeit a little wet) I expect we will need to be asking some questions about whether the automated flight termination system worked as it was designed - and if it did - who didn't trigger a manual termination and why not? Dangerous as hell.
