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Recent Posts
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General Discussion / Re: Skylab launch video and animation
« Last post by JayUtah on March 18, 2024, 01:33:48 PM »Actually now that I think about it, I'm not sure they did any aerodynamic testing on the shield at all. I recall that being a big part of the incident investigation afterward.
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General Discussion / Re: Skylab launch video and animation
« Last post by JayUtah on March 18, 2024, 10:13:08 AM »Unanticipated aerodynamic effects.
The shield was in fact very flimsy, because it didn't need to have much structural strength to perform its task on orbit. What most people don't realize is how the shield was meant to deploy. It was supposed to spring outward and form a larger cylinder than in the stowed-for-launch configuration (with foldouts to create the larger perimeter needed).
One of the fairings for the tunnels containing cabling and other conduits down the side of the payload created a shock wave that pulled the nearby leading edge of the shield away just enough for ram air to get underneath it. Once that happens, the shield is not nearly strong enough to withstand the slipstream.
The shield was made from 22-gauge aerospace aluminum, which makes it about twice as thick as an aluminum pie plate, or about twice as thick as your HVAC ductwork. For launch, it was held tight against the lab wall by its deployment mechanism. The aerodynamic test regime had not included protrusions such as fairings.
The shield was in fact very flimsy, because it didn't need to have much structural strength to perform its task on orbit. What most people don't realize is how the shield was meant to deploy. It was supposed to spring outward and form a larger cylinder than in the stowed-for-launch configuration (with foldouts to create the larger perimeter needed).
One of the fairings for the tunnels containing cabling and other conduits down the side of the payload created a shock wave that pulled the nearby leading edge of the shield away just enough for ram air to get underneath it. Once that happens, the shield is not nearly strong enough to withstand the slipstream.
The shield was made from 22-gauge aerospace aluminum, which makes it about twice as thick as an aluminum pie plate, or about twice as thick as your HVAC ductwork. For launch, it was held tight against the lab wall by its deployment mechanism. The aerodynamic test regime had not included protrusions such as fairings.
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General Discussion / Re: Apollo 11 video feed delay?
« Last post by Mag40 on March 18, 2024, 06:21:03 AM »65
General Discussion / Re: Apollo 11 video feed delay?
« Last post by David Ridlen on March 18, 2024, 05:51:00 AM »Sorta. He replies as if open to admitting to being wrong about fakery, remains civil, and at least partly admits when debunked.
I am defending the impossibility of faking artificial lighting in the Apollo visual record. He is mostly arguing how all photographic evidence can be faked one way or another.
He finds the video and 16mm footage more compelling to argue with, than any still images, since the camera and things move around, conceding that they cannot be post-composited. For the moment, he is ignoring what I consider the most compelling visual recording- 16mm Apollo 15 footage of EVA 2 (also EVA 3), between Station 6 and 6a- It cannot be miniature since uncut footage has astronauts walk in front of camera, and shows miles of evenly lit terrain with sharp, unidirectional shadows, where it is impossible to use or hide lights. I will return to that.
But after days of debate on this frame-rate point (among others), he has retreated to claiming NASA is at least lying about a live feed, but not that it proves anything one way or the other. But I know that if you dont debunk a particular detail they gather all wagons around that last hill. So I was looking for a bit more definitive info on the A11 feed delay.
I am defending the impossibility of faking artificial lighting in the Apollo visual record. He is mostly arguing how all photographic evidence can be faked one way or another.
He finds the video and 16mm footage more compelling to argue with, than any still images, since the camera and things move around, conceding that they cannot be post-composited. For the moment, he is ignoring what I consider the most compelling visual recording- 16mm Apollo 15 footage of EVA 2 (also EVA 3), between Station 6 and 6a- It cannot be miniature since uncut footage has astronauts walk in front of camera, and shows miles of evenly lit terrain with sharp, unidirectional shadows, where it is impossible to use or hide lights. I will return to that.
But after days of debate on this frame-rate point (among others), he has retreated to claiming NASA is at least lying about a live feed, but not that it proves anything one way or the other. But I know that if you dont debunk a particular detail they gather all wagons around that last hill. So I was looking for a bit more definitive info on the A11 feed delay.
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General Discussion / Re: Apollo 11 video feed delay?
« Last post by Zakalwe on March 18, 2024, 05:06:36 AM »So he's not questioning that the events took place as seen, just that it took a bit longer to process?
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General Discussion / Apollo 11 video feed delay?
« Last post by David Ridlen on March 18, 2024, 12:21:33 AM »Does anyone know where specifics are about how long the Apollo 11 video frame conversion process took? An Apollo denier with some video experience is insisting it would have taken hours to process, preventing a live feed. Offhand, I dont find precise info about how long the scan rate conversion (10 fps to NTSC) took to record and send. The best I can find is this- https://www.parkes.atnf.csiro.au/news_events/apollo11/The_Apollo11_SSTV_Tapes_Search.pdf but it does not say how long the conversion process took.
The denier's most recent claim is:
"...The TV signal had to have a significant delay in relation to the communication because the speed of recording on the hard disk and on the tape is limited by the speed of reading, writing and the speed of rotation of the disk and tape. Considering that the hard disk was returning the signal for rebroadcasting and scanning, it is clear that the minimum delay of the TV signal is 3 hours in relation to communication. Even if they managed to spin the hard drive at the speed of light and execute the whole process at the speed of light, the delay would be at least 20 frames every second. So definitely someone had to synchronize the communication and the video recording, and given that the communication was already in the live program of many televisions, it is logical that the televisions had to do that work. Assuming they knew exactly how long the delay was, they could do it in two ways. The first is to slow down the tone until the TV image reaches the communication and the second is to speed up the image. Since it is not visible in the live broadcast that they slowed down the tone, it remains that they could only slow down the image. All televisions that broadcast live broadcasts had to synchronize at the same time. Now there is another problem, and that is that they had to record all the video material first, and only then synchronize it, again all at the same time. So NASA and the TV stations that broadcast the live broadcast lied."
Thanks!
The denier's most recent claim is:
"...The TV signal had to have a significant delay in relation to the communication because the speed of recording on the hard disk and on the tape is limited by the speed of reading, writing and the speed of rotation of the disk and tape. Considering that the hard disk was returning the signal for rebroadcasting and scanning, it is clear that the minimum delay of the TV signal is 3 hours in relation to communication. Even if they managed to spin the hard drive at the speed of light and execute the whole process at the speed of light, the delay would be at least 20 frames every second. So definitely someone had to synchronize the communication and the video recording, and given that the communication was already in the live program of many televisions, it is logical that the televisions had to do that work. Assuming they knew exactly how long the delay was, they could do it in two ways. The first is to slow down the tone until the TV image reaches the communication and the second is to speed up the image. Since it is not visible in the live broadcast that they slowed down the tone, it remains that they could only slow down the image. All televisions that broadcast live broadcasts had to synchronize at the same time. Now there is another problem, and that is that they had to record all the video material first, and only then synchronize it, again all at the same time. So NASA and the TV stations that broadcast the live broadcast lied."
Thanks!
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General Discussion / Re: Skylab launch video and animation
« Last post by bknight on March 16, 2024, 11:50:13 AM »When the micrometeoroid shield and other structures detached from the payload during ascent, they damaged the linear shaped charge used to separate the interstage. The damage created a discontinuity in the explosive material. Because only one detonator was provided, the charge only progressed as far as the discontinuity. Ordinarily it would race all the way around the vehicle in a tiny fraction of a second. For this reason, any time these days we use the same separation method, we provide a detonator at each end of the charge. But more often we use mechanical designs that require only one small detonator that fails the mechanical attachment uniformly.Did they ever determine why the shield detached?
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Announcements / Re: New web hosting and down time.
« Last post by Ranb on March 12, 2024, 11:30:08 PM »Working fine, thanks.
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General Discussion / Re: Skylab launch video and animation
« Last post by JayUtah on March 11, 2024, 10:22:16 AM »When the micrometeoroid shield and other structures detached from the payload during ascent, they damaged the linear shaped charge used to separate the interstage. The damage created a discontinuity in the explosive material. Because only one detonator was provided, the charge only progressed as far as the discontinuity. Ordinarily it would race all the way around the vehicle in a tiny fraction of a second. For this reason, any time these days we use the same separation method, we provide a detonator at each end of the charge. But more often we use mechanical designs that require only one small detonator that fails the mechanical attachment uniformly.