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NASA Studying Russian 12-month Plan
"jeff findley" wrote in message ... "Greg D. Moore \(Strider\)" writes: "jeff findley" wrote in message ... (dave schneider) writes: I didn't yet get the right google terms to find the answer to -- How many Mir astronauts were on 6 month missions? -- How many Mir astronauts were on 9 month missions? -- How many Mir astronauts were on 12-14 month missions? 20 longest human flights (descended order) http://space.kursknet.ru/cosmos/english/other/long.sht Note however, the American's aren't far behind. Shannon Lucid is in there at 188+ days. While true this was on a Mir mission, correct? The Russians were in control of Mir while the US was participating. Now ISS is (apparantly) being run by the US with the Russians participating. Yes, but I'm not sure what your point is. I was just offering a data point. Jeff -- Remove "no" and "spam" from email address to reply. If it says "This is not spam!", it's surely a lie. |
#92
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NASA Studying Russian 12-month Plan
"Derek Lyons" wrote in message ... "Greg D. Moore \(Strider\)" wrote: "bob haller" wrote in message Theres no reason a crew couldnt communicate often with their family. Other than risking the security of the sub. Keep in mind that hal regards PR and appearance far higher than actual performance. Well of course? As the idea was to basically "leave port and not be seen again until we get home" the more time you spend at com depth, the greater risk you have of exposing your position and what you're doing. Keep in mind that since SSBN's were configured to receive The Word 24/7, and that The Word was never sent, there was a great deal of unused bandwidth. My understanding is that at station depth the only real signal the SSBNs could get was the ELF (?) signal which was on the order of bits per second? i.e. it made a 300 baud modem look fast. So, assuming 30 bits/second, or roughly 4 ASCII characters/second. 240 characters per minute. Hm, yeah, I guess that's higher than I initially thought. Given the great deal of bandwidth unused, it was easy to send such messages to the boat. This was actually a measure to *increase* security. Even if you can't read someone's messages, knowing who is talking to who, and how much, and when, can give valuable indicators that Something is Up. (This is called traffic analysis, http://en.wikipedia.org/wiki/Traffic_analysis .) To prevent the black hats from deriving this information from the tempo and volume on the SSBN broadcast, the 'cast was kept going 24/7. Hmm, makes perfect sense. You can separate the wheat from the chaff, but presumably the enemy can't, so they never know if the actual content of the signal is changing. This doesn't of course apply to SSN's which weren't/aren't on 24/7 alert, and pick up their messages by coming to periscope depth at intervals and snagging their messages from SSIXS. Even then I'd think the ones on patrol would tend to stay hidden enough to track and surprise the enemy. Transmissions from a submarine are of course a great security risk, and are thus restricted. Obviously. Though I wouldn't be surprised if Bob thought this was somehow unfair to the families who couldn't hear from their loved ones on a daily basis. :-/ D. -- Touch-twice life. Eat. Drink. Laugh. |
#93
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NASA Studying Russian 12-month Plan
"Greg D. Moore \(Strider\)" wrote:
My understanding is that at station depth the only real signal the SSBNs could get was the ELF (?) signal which was on the order of bits per second? You assume our antennae and our hull are at the same depth, they aren't. Underway we stream a buoy above/behind the boat that carries our antennae. i.e. it made a 300 baud modem look fast. So, assuming 30 bits/second, or roughly 4 ASCII characters/second. 240 characters per minute. Hm, yeah, I guess that's higher than I initially thought. It wasn't ASCII, it was alphanumeric teletype code. 30 bits/sec = 6 chars/sec = 360 characters a minute. 360 chars/min *60mins/hour *24hours/day = 518,400 chars/day. Not much by 'modern' standards, but a half a meg of text is a substantial chunk. Even more when you consider a goodly number of the 'words' are actually abbreviations. D. -- Touch-twice life. Eat. Drink. Laugh. |
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NASA Studying Russian 12-month Plan
In article , derekl1963
@nospamyahoo.com says... Given the great deal of bandwidth unused, it was easy to send such messages to the boat. How much bandwidth was really required? A message of "uh-oh, attack the *******s according to plan CRM114" requires few bits, and if that message is delayed for 60 or 120 seconds, it doesn't make much difference. *Reliability* constraints are quite extreme, but I don't see high bandwidth as necessary. -- Kevin Willoughby lid Imagine that, a FROG ON-OFF switch, hardly the work for test pilots. -- Mike Collins |
#95
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NASA Studying Russian 12-month Plan
Obviously. Though I wouldn't be surprised if Bob thought this was somehow unfair to the families who couldn't hear from their loved ones on a daily basis. :-/ Actually I heard some exotic technology allowed increased communication. Today its mostly nmeaningless, who are we hiding from.??? HAVE A GREAT DAY! |
#96
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NASA Studying Russian 12-month Plan
fference. *Reliability* constraints are quite
extreme, but I don't see high bandwidth as necessary. -- What you do is send out a stready stream 24/7 some legit other filler to confuse the enemy HAVE A GREAT DAY! |
#97
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NASA Studying Russian 12-month Plan
Kevin Willoughby wrote:
In article , derekl1963 says... Given the great deal of bandwidth unused, it was easy to send such messages to the boat. How much bandwidth was really required? A message of "uh-oh, attack the *******s according to plan CRM114" requires few bits, and if that message is delayed for 60 or 120 seconds, it doesn't make much difference. In reality? Not very much. The problem however was twofold: We still needed a higher bandwidth channel to receive routine operational traffic, the frequencies available were limited by physics and international treaty, and we needed to hide exactly what was being communicated and when. (As I said in an earlier message, knowing who is talking to who, and when, and how much, is almost as valuable as knowing exactly what is being said.) The answer was to combine all possible uses onto one higher bandwith circuit. *Reliability* constraints are quite extreme, but I don't see high bandwidth as necessary. Indeed, high reliability and high connectivity are the twin principles that drive the design of the entire communications system. Not only are there multiple transmission sites for the main broadcast, there are backup methods of conveying the important stuff as well. However, as I point out above, the need for and availability of higher bandwith was driven both other issues than immediate tactical need. D. -- Touch-twice life. Eat. Drink. Laugh. |
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NASA Studying Russian 12-month Plan
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#99
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NASA Studying Russian 12-month Plan
In article , derekl1963
@nospamyahoo.com says... Kevin Willoughby wrote: *Reliability* constraints are quite extreme, but I don't see high bandwidth as necessary. Indeed, high reliability and high connectivity are the twin principles that drive the design of the entire communications system. Not only are there multiple transmission sites for the main broadcast, there are backup methods of conveying the important stuff as well. Is any of this publicly available? It would be quite a case-study in reliability engineering. -- Kevin Willoughby lid Imagine that, a FROG ON-OFF switch, hardly the work for test pilots. -- Mike Collins |
#100
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NASA Studying Russian 12-month Plan
Kevin Willoughby wrote:
In article , derekl1963 says... Kevin Willoughby wrote: *Reliability* constraints are quite extreme, but I don't see high bandwidth as necessary. Indeed, high reliability and high connectivity are the twin principles that drive the design of the entire communications system. Not only are there multiple transmission sites for the main broadcast, there are backup methods of conveying the important stuff as well. Is any of this publicly available? It would be quite a case-study in reliability engineering. The only public sources (which go beyond what I have written) of which I am aware are largely dated, and concentrate more on the politics than on the engineering. (I.E. mostly critical of the 'warfighting' of the Reagan era vice the dying remnants of 'wargasm' that proceeded them.) Those that don't fit that niche are of the 'gee-whiz Buck Rogers' variety. Also most of them concentrate mostly on the very different problems that the USAF faced. Spinardi ("From Polaris to Trident : The Development of US Fleet Ballistic Missile Technology") covers some of this if you can get a copy, and the best (only) technical work on the SSBN/FBM system. D. -- Touch-twice life. Eat. Drink. Laugh. |
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