tag:blogger.com,1999:blog-3673435362400368888.post4850024111306059795..comments2023-04-01T13:39:24.156-07:00Comments on RocketsAndSuch: Taking ChancesRocket Manhttp://www.blogger.com/profile/05109496878476775729noreply@blogger.comBlogger11125tag:blogger.com,1999:blog-3673435362400368888.post-42891894006635884882008-11-18T05:29:00.000-08:002008-11-18T05:29:00.000-08:00If these LOC numbers are true, then there should b...If these LOC numbers are true, then there should be at a bare minimum an immediate effort to qualify other hardware for getting Orion to orbit, and to speed up Dragon. Each time a shuttle was lost, we had 3 years' downtime. If we aren't going to meet the magical 1/1000 target (which I'll believe after several hundred successful missions) then it is really necessary to have Option B.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3673435362400368888.post-1295024092797412942008-11-18T04:57:00.000-08:002008-11-18T04:57:00.000-08:00What is really funny is that these calcs are based...What is really funny is that these calcs are based on a lot of very shaky assumptions. The LAS is a case in point. The present ARES LAS is enormously powerful and has to be to escape from a SRB flying right towards you due to the lack of thrust termination. The overall safety of such a system is clearly compromised as compared to a liquid booster system where you can stop thrusting and use a smaller, simpler LAS. However I've not seen any direct comparison of these two system concepts. ARES/Orion is heavily reliant on the LAS to address failure modes.<BR/><BR/>In a similar fashion the new damping systems on ARES have no direct flight experience and their reliability is a shot in the dark. You can of course approximate things but you are making gross assumptions about how this system is related to historical systems. The new J-2? is also a completely new engine with only minimal real carry-over from Apollo vintage hardware and it is being subjected to wholly new environments. <BR/><BR/>This means that the real reliability is not really knowable on the day of first flight. You have perturbed so many things that you are disconnected from prior demonstrated performance. You can brandish all sorts of numbers around but the real-world reliability is a guess.<BR/><BR/>This single argument should be sufficient to light the way towards the use of existing, flight proven EELV vehicles that have been shown to work as complete systems. Their reliability is demonstrated- not merely estimated. Furthermore their flight rates will be far higher than a NASA-only ARES vehicle and hence demonstrated reliability will climb at a far greater rate. By the time Orion becomes a payload on a Delta or Atlas those vehicle systems will have flown dozens of times. By the time Orion is headed for the Moon they will have flown hundreds of times- not a mere handful. <BR/><BR/>Those EELV's will have also flown missions that are far more demanding of vehicle systems than a single burn LEO launch. This represents a stress test of the vehicle from the perspective of Orion. This confers even greater confidence for the crewed launches.<BR/><BR/>There are hard paths and easy paths. Which one can we really afford?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3673435362400368888.post-43178897694043594012008-11-18T04:49:00.000-08:002008-11-18T04:49:00.000-08:00The key to 1 in 30 is getting the crew out of the ...The key to 1 in 30 is getting the crew out of the launch and entry spacesuits within 30 min. of landing. The 24 hour passive cooling capability was deleted for Ares weight. So now they must get out within 30 min. Not a simple task floating in the north Atlantic with injured or sick crew trying to get 6 people out of the suites, getting the snorkel up before the heat takes everyone out and some pass.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3673435362400368888.post-76999753694339831992008-11-17T19:48:00.000-08:002008-11-17T19:48:00.000-08:00Shuttle has backup systems piled upon backup syste...Shuttle has backup systems piled upon backup systems. I think most of Orion's backup systems got removed during one of the rounds of weight scrubbing, to be added back later if necessary. If the current numbers are 1:30, then I'd say they need to be added back.<BR/><BR/>This isn't going to be good for Orion's weight numbers - applying a patch in one place just springs a leak somewhere else.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3673435362400368888.post-74826384272117641202008-11-17T18:41:00.000-08:002008-11-17T18:41:00.000-08:00We don't lie! We bend data.Ares manager...We don't lie! We bend data.<BR/>Ares manager...Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3673435362400368888.post-24964486631511383462008-11-17T14:44:00.000-08:002008-11-17T14:44:00.000-08:00i'm hearing 1 in 30 for ISS missions, too. Unless ...i'm hearing 1 in 30 for ISS missions, too. Unless they lie about it...Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3673435362400368888.post-81926322129172207932008-11-17T09:27:00.000-08:002008-11-17T09:27:00.000-08:00Are you sure that isn't the LOC for the lunar miss...Are you sure that isn't the LOC for the lunar missions? I have seen that same number (1:30) for the Honeymooners flight ("to the Moon, Alice!"), but most recent Ares/Orion numbers (although not as recent as yours) are better than 1:1000.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3673435362400368888.post-78423208743411678082008-11-17T04:18:00.000-08:002008-11-17T04:18:00.000-08:00This continual moving of goalposts to preseve the ...This continual moving of goalposts to preseve the Chief Administrator's pet project has finally moved from black farce to felonious malfeasance. To deliberately reduce the safety of a design to such a low level is symptomatic a corporate culture more focussed on internal politics than the end product. <BR/><BR/>I feel that the time has come for wide-ranging bloodletting at NASA to clear out all of the Orion/Ares drones for whom even the lives of astronauts are not as important as being seen to be right. Give their jobs to people who actually care about what they are trying to do rather than just on drawing their next paycheque.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3673435362400368888.post-87633494353043354272008-11-16T20:56:00.000-08:002008-11-16T20:56:00.000-08:00I'm trying to think of reasons why Orion will be l...I'm trying to think of reasons why Orion will be less safe than the shuttle it's replacing. The fact that there's a crew escape system should at least make the ascent portion of the mission safer than shuttle. But there could always be risks on-orbit or during reentry that are worth noting. Orion won't be monostable, for instance. But I still believe that the capsule design should be inherently safer than the complex wonder known as shuttle.Mr. Xhttps://www.blogger.com/profile/08537371901494918449noreply@blogger.comtag:blogger.com,1999:blog-3673435362400368888.post-35741481706883917832008-11-16T14:50:00.000-08:002008-11-16T14:50:00.000-08:00The IG will do nothing (down boy, that’s a good do...The IG will do nothing (down boy, that’s a good dog). Pray for the crews, the Ares managers do not care.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3673435362400368888.post-58782860263212843252008-11-16T13:31:00.000-08:002008-11-16T13:31:00.000-08:00Echo, echoo, echooo....guess nobody's listenin'. ...Echo, echoo, echooo....guess nobody's listenin'. Want some cheese do go with your whine?Anonymousnoreply@blogger.com