#1
|
|||
|
|||
For Want Of A Bolt
My latest Fox column is up, in which I ruminate on the high cost of
satellites: http://www.foxnews.com/story/0,2933,97611,00.html -- simberg.interglobal.org * 310 372-7963 (CA) 307 739-1296 (Jackson Hole) interglobal space lines * 307 733-1715 (Fax) http://www.interglobal.org "Extraordinary launch vehicles require extraordinary markets..." Swap the first . and @ and throw out the ".trash" to email me. Here's my email address for autospammers: |
#3
|
|||
|
|||
For Want Of A Bolt
"Rand Simberg" wrote in message ... My latest Fox column is up, in which I ruminate on the high cost of satellites: http://www.foxnews.com/story/0,2933,97611,00.html I agree that launch costs are too high, satellites costs are too high and mass production would help. I have to disagree on one major point. Launch costs adjusted for inflation have been falling for years while the average price of satellites have not. Launch costs are only a small fraction of total costs. It is the satellites that are not changing to meet lower launch costs not high launch costs that keep the satellite costs high. |
#4
|
|||
|
|||
For Want Of A Bolt
On Thu, 18 Sep 2003 01:26:09 CST, in a place far, far away,
(Derek Lyons) made the phosphor on my monitor glow in such a way as to indicate that: (Rand Simberg) wrote: My latest Fox column is up, in which I ruminate on the high cost of satellites: http://www.foxnews.com/story/0,2933,97611,00.html From the article: "But that doesn't explain why similar systems designed for marine use (the ocean has extremely high positive pressures, and seawater is an extremely corrosive environment) can be built for orders of magnitude less." Please provide a cite of a marine system of the equivalent complexity and mission of the weather sat with a design lifetime of years or decades. (Or any marine system with those kinds of lifetime requirements.) You seem to miss the point. "Those lifetime requirements" are exactly the point. If it were cheap and easy to get to space, it wouldn't necessarily have those lifetime requirements. -- simberg.interglobal.org * 310 372-7963 (CA) 307 739-1296 (Jackson Hole) interglobal space lines * 307 733-1715 (Fax) http://www.interglobal.org "Extraordinary launch vehicles require extraordinary markets..." Swap the first . and @ and throw out the ".trash" to email me. Here's my email address for autospammers: |
#5
|
|||
|
|||
For Want Of A Bolt
h (Rand Simberg) wrote:
On Thu, 18 Sep 2003 01:26:09 CST, in a place far, far away, (Derek Lyons) made the phosphor on my monitor glow in such a way as to indicate that: (Rand Simberg) wrote: My latest Fox column is up, in which I ruminate on the high cost of satellites: http://www.foxnews.com/story/0,2933,97611,00.html From the article: "But that doesn't explain why similar systems designed for marine use (the ocean has extremely high positive pressures, and seawater is an extremely corrosive environment) can be built for orders of magnitude less." Please provide a cite of a marine system of the equivalent complexity and mission of the weather sat with a design lifetime of years or decades. (Or any marine system with those kinds of lifetime requirements.) You seem to miss the point. "Those lifetime requirements" are exactly the point. If it were cheap and easy to get to space, it wouldn't necessarily have those lifetime requirements. In other words, you have made a claim you are unwilling to back up. D. -- The STS-107 Columbia Loss FAQ can be found at the following URLs: Text-Only Version: http://www.io.com/~o_m/columbia_loss_faq.html Enhanced HTML Version: http://www.io.com/~o_m/columbia_loss_faq_x.html Corrections, comments, and additions should be e-mailed to , as well as posted to sci.space.history and sci.space.shuttle for discussion. |
#6
|
|||
|
|||
For Want Of A Bolt
On Fri, 19 Sep 2003 00:29:23 CST, in a place far, far away,
(Derek Lyons) made the phosphor on my monitor glow in such a way as to indicate that: Please provide a cite of a marine system of the equivalent complexity and mission of the weather sat with a design lifetime of years or decades. (Or any marine system with those kinds of lifetime requirements.) You seem to miss the point. "Those lifetime requirements" are exactly the point. If it were cheap and easy to get to space, it wouldn't necessarily have those lifetime requirements. In other words, you have made a claim you are unwilling to back up. rolling eyes -- simberg.interglobal.org * 310 372-7963 (CA) 307 739-1296 (Jackson Hole) interglobal space lines * 307 733-1715 (Fax) http://www.interglobal.org "Extraordinary launch vehicles require extraordinary markets..." Swap the first . and @ and throw out the ".trash" to email me. Here's my email address for autospammers: |
#7
|
|||
|
|||
For Want Of A Bolt
(Derek Lyons) wrote in message ...
h (Rand Simberg) wrote: "But that doesn't explain why similar systems designed for marine use (the ocean has extremely high positive pressures, and seawater is an extremely corrosive environment) can be built for orders of magnitude less." Please provide a cite of a marine system of the equivalent complexity and mission of the weather sat with a design lifetime of years or decades. (Or any marine system with those kinds of lifetime requirements.) Transatlantic cables come close. Before fiber optics, these had repeaters every few km. Since they were in series, ALL of the repeaters must work. If I remember correctly, they were designed so the cable as a whole had a 20 year lifetime. Using good old conservative engineering, the even made this work with vacuum tubes(!). Needless to say this was one of the first applications of transistors. Lou Scheffer |
#8
|
|||
|
|||
For Want Of A Bolt
(Derek Lyons) wrote in message ...
h (Rand Simberg) wrote: "But that doesn't explain why similar systems designed for marine use (the ocean has extremely high positive pressures, and seawater is an extremely corrosive environment) can be built for orders of magnitude less." Please provide a cite of a marine system of the equivalent complexity and mission of the weather sat with a design lifetime of years or decades. (Or any marine system with those kinds of lifetime requirements.) Here is from an article describing using an old cable (no longer economical) for seismic research in mid-ocean (it provides power and communication). http://www.terrapub.co.jp/journals/E...2/50110913.pdf This particular cable was from Guam to Japan and built in 1964. The cut the cable, dredged up one end, then spliced in a seismometer and extra cable, then dredged up the other end and connected them. It's easier than space, but still non-trivial. "The cable length between two adjacent repeaters is 37.08 km (20 nautical miles). A repeater comprises dual sets of vacuums tube amplifiers, because vacuum tubes were the most reliable electronic devices in early 60 s when the system was designed. The first question was on remaining life of the cable system because the official life of the system was 25 years. The design lives of repeaters and equalizers, however, were roughly more than 50 years and the estimated lives of submarine cables were more than the lives of the electronics (Dodeman, personal communication). " Lou Scheffer |
#9
|
|||
|
|||
For Want Of A Bolt
(Lou Scheffer) wrote in message om...
(Derek Lyons) wrote in message ... h (Rand Simberg) wrote: "But that doesn't explain why similar systems designed for marine use [...] can be built for orders of magnitude less." Please provide a cite of a marine system of the equivalent complexity and mission of the weather sat with a design lifetime of years or decades. (Or any marine system with those kinds of lifetime requirements.) Transatlantic cables come close. Before fiber optics, these had repeaters every few km. Since they were in series, ALL of the repeaters must work. If I remember correctly, they were designed so the cable as a whole had a 20 year lifetime. Using good old conservative engineering, the even made this work with vacuum tubes(!). Needless to say this was one of the first applications of transistors. Oops - this was NOT one of the first uses of transistors. Another article states that they were still built with vacuum tubes in 1964, 10 years after transistors were used for other applications, since transistors were not yet proven to be more reliable. In retrospect this makes perfect sense - any reliability conscious field will not rush to adapt new technology, no matter how promising, if the old technology is working at least OK. Lou Scheffer |
#10
|
|||
|
|||
For Want Of A Bolt
In article ,
Lou Scheffer wrote: Transatlantic cables... Oops - this was NOT one of the first uses of transistors. Another article states that they were still built with vacuum tubes in 1964, 10 years after transistors were used for other applications, since transistors were not yet proven to be more reliable. In retrospect this makes perfect sense - any reliability conscious field will not rush to adapt new technology, no matter how promising, if the old technology is working at least OK. I'm told that the component-qualification rules for undersea-cable repeaters make space-qualification procedures look amateurish. -- MOST launched 1015 EDT 30 June, separated 1046, | Henry Spencer first ground-station pass 1651, all nominal! | |
Thread Tools | |
Display Modes | |
|
|