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Light This Candle
I guess that it might be off-topic to this newsgroup G, but I'm a little
surprised that no one has talked about the recently released biography of Alan Shepard by Neal Thompson. I just finished it a couple of days ago, and was wondering what some of you think about it. Reading the back cover blurb, Homer Hickam says that although he thought he "knew pretty much everything about the history of the American space effort" he "learned something new" on "nearly every page of this fine book." After reading it I wonder how much I learned is true, based on some of the technical statements. For example on page 255 during the description of his Freedom 7 flight I "learned:" "Shepard then had to align the capsule at the precise angle so that the asbestos-covered bottom of the capsule would absorb the intense heat to come." Asbestos-covered????? "If he was off by just a degree or two, the capsule could be thrown dangerously far off course." True? The Mercury spacecraft didn't generate much lift did it? And, it doesn't seem to me that there would be very much to affect what was basically a ballistic trajectory. Then on page 328 we have: "The soul-searching, investigations, shake-ups, and restructuring that had occurred throughout NASA after the Apollo 1 disaster resulted in a completely redesigned Apollo capsule -- and a ridiculously huge new rocket. Apollo flights scheduled to begin in October of 1968 would be boosted from earth atop a Saturn 5 rocket, which Wernher von Braun had spent nearly a decade creating." I never new that the Saturn V hadn't been considered for Apollo before the fire, nor that Apollo 7 had used a Saturn V rather than a Saturn Ib!!!!! And on pp385-86 "Shepard was disgusted by the Challenger tragedy, which was caused by a faulty valve." Faulty valve????? I hope that the author got more right in his description of the personalities, but I wasn't impressed by his fact-checking on the technical details. Comments? |
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I finished the book a couple of weeks ago. Sure, it's full of historical and
technical inaccuracies and contains a lot of heresay, but I think Thompson was going for a character study, as in "what was Shepard really like." Everyone knows the "Smilin' Al versus the Icy Commander" duality, so he probably figured we needed to fill in the middle portions of Al's psyche. Reading it this way, and not as history, I found it to be a pretty good book. JW Whizzospace http://whizzospace.com ----== Posted via Newsfeed.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeed.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= 19 East/West-Coast Specialized Servers - Total Privacy via Encryption =--- |
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"John Whisenhunt" wrote:
I finished the book a couple of weeks ago. Sure, it's full of historical and technical inaccuracies and contains a lot of heresay, but I think Thompson was going for a character study, as in "what was Shepard really like." Everyone knows the "Smilin' Al versus the Icy Commander" duality, so he probably figured we needed to fill in the middle portions of Al's psyche. Reading it this way, and not as history, I found it to be a pretty good book. How do you know it's a reasonable illumination of this facet, when it's so filled with other inaccuracies? D. -- Touch-twice life. Eat. Drink. Laugh. |
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In article ,
Rick DeNatale wrote: "If he was off by just a degree or two, the capsule could be thrown dangerously far off course." True? The Mercury spacecraft didn't generate much lift did it? In fact, none. It was balanced to put the center of mass on the centerline, avoiding generating any lift... and if memory serves, reentry was normally done in a slow roll so that any residual lift would average to zero and the trajectory would be purely ballistic. And, it doesn't seem to me that there would be very much to affect what was basically a ballistic trajectory. Correct. For the orbital Mercury flights, the *retrofire* attitude had to be moderately precise to come down at the planned point -- although the nominal retrofire attitude was chosen mostly to minimize sensitivity to attitude errors -- but during reentry, the spacecraft was basically stable in only one position. The main attitude-control issue during reentry was damping out oscillations, and that was more for crew comfort than anything else. (Both Glenn and Carpenter ran out of attitude-control fuel midway through descent, and were none the worse for it.) Shepard did do a retrofire, with careful attitude control during it, but that was a rehearsal for the orbital flights rather than anything that mattered to his flight. It sounds like the writer did a bit of research but not as much as he should have; he didn't really grasp the differences between the suborbital and orbital flights. -- MOST launched 30 June; science observations running | Henry Spencer since Oct; first surprises seen; papers pending. | |
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Most noticable place I have seen this is on the Apollo 10 CM at the Science
Museum in London, UK. It's displayed in such a way as most of the heat shield is visible. Adam "OM" om@our_blessed_lady_mary_of_the_holy_NASA_researc h_facility.org wrote ...One clue as to whether or not a conical, rear-end-down capsule has any lift capabilites designed into it is to examine the heat shield after reentry. If the striations and scoring from the reentry heat do not appear to radiate from the dead center of the shield, then it's a sure sign the C/M is offset to induce lift during reentry. You'll see it dead center on Mercury heat shields, but obviously offset on Gemini. OM |
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On Fri, 07 May 2004 16:13:02 -0400, Rick DeNatale
wrote: True? The Mercury spacecraft didn't generate much lift did it? And, it doesn't seem to me that there would be very much to affect what was basically a ballistic trajectory. ....Correct. In order for the reentry to be a purely ballistic one, the Mercury capsule & heatshield were designed so that the the center of mass was smack dab right on on the middle of the heat shield. This would eliminate any lift characteristics from the shield durign reentry. In addition, there was a slow roll induced during reentry so that any lift that might still result would be averaged out and nulled. ....One clue as to whether or not a conical, rear-end-down capsule has any lift capabilites designed into it is to examine the heat shield after reentry. If the striations and scoring from the reentry heat do not appear to radiate from the dead center of the shield, then it's a sure sign the C/M is offset to induce lift during reentry. You'll see it dead center on Mercury heat shields, but obviously offset on Gemini. OM -- "No ******* ever won a war by dying for | http://www.io.com/~o_m his country. He won it by making the other | Sergeant-At-Arms poor dumb ******* die for his country." | Human O-Ring Society - General George S. Patton, Jr |
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On Sat, 8 May 2004 11:27:49 +0100, "adam bootle"
wrote: "OM" om@our_blessed_lady_mary_of_the_holy_NASA_researc h_facility.org wrote ...One clue as to whether or not a conical, rear-end-down capsule has any lift capabilites designed into it is to examine the heat shield after reentry. If the striations and scoring from the reentry heat do not appear to radiate from the dead center of the shield, then it's a sure sign the C/M is offset to induce lift during reentry. You'll see it dead center on Mercury heat shields, but obviously offset on Gemini. Most noticable place I have seen this is on the Apollo 10 CM at the Science Museum in London, UK. It's displayed in such a way as most of the heat shield is visible. ....One of the photos on my A17 page shows the striations, but not as clearly as it should. The Gemini ones on the Gordo Cooper's Used Spacecrafts page shows them better. One of the things I plan to do in the next few months is to take my Canon Digital Rebel down to Space Center Disney and redo quite a few of the photos from my disasterous trip pages. Of course, the only shots I still can't add are the mug shots of the two ghetto thugs who robbed me at gunpoint across the street from the Outpost. I'll just simply make up for that by including shots from inside the outpost this time. OM -- "No ******* ever won a war by dying for | http://www.io.com/~o_m his country. He won it by making the other | Sergeant-At-Arms poor dumb ******* die for his country." | Human O-Ring Society - General George S. Patton, Jr |
#9
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On Fri, 07 May 2004 22:14:33 -0400, Kevin Willoughby wrote:
In article , says... Asbestos-covered????? No. Beryllium. (Orbital Mercurys had a different heat shield.) Yes, I already knew that. "If he was off by just a degree or two, the capsule could be thrown dangerously far off course." True? Of course not. Ask Scott Carpenter. He was off by 30+ degrees. He landed a bit off course, but not dangerously so. He was also re-entering from orbit a significant difference from Shepard's ballistic trajectory, which was my point. Note that my question markes were intended to be rhetorical. |
#10
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On Sat, 08 May 2004 04:58:32 +0000, Henry Spencer wrote:
In article , Rick DeNatale wrote: And, it doesn't seem to me that there would be very much to affect what was basically a ballistic trajectory. Correct. For the orbital Mercury flights, the *retrofire* attitude had to be moderately precise to come down at the planned point -- although the nominal retrofire attitude was chosen mostly to minimize sensitivity to attitude errors -- but during reentry, the spacecraft was basically stable in only one position. Due to the spring-loaded destabilizing flap which was deployed at tower separation, and prevented a heatshield up aerodynamically stable mode. The flap also covered the forward (or probably more technically accurately aft) horizon sensor in the antenna cannister. It's one of those simple mechanical designs which showed up in early "rocket science." Another example I really like was the way that the nose fairing panels were secured in the Bumper-WAC, they were actually held together with something like sturdier versions of the hook fasteners used on gates, which where in the path of the WAC Corporal's fins When the WAC fired it just knocked them out of the way. I found some diagrams of this when I was searching in the NASM library and thought "what a cool design!" |
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