ApolloHoax.net
Apollo Discussions => The Reality of Apollo => Topic started by: raven on November 02, 2013, 01:03:37 AM
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All right, I have a bit of a question. I know that after Apollo 11 ,but before the J-class missions, they set up an S-band antenna on the lunar surface to transmit the colour TV signals. However, how did they transmit those (http://www.youtube.com/watch?v=YEEIJYrXn9s)missions (http://www.youtube.com/watch?v=IhXsjENGrk0) first steps than in colour?
I know I am missing something, but what?
Moreover, they didn't use such an antenna on the J-class missions but used the antenna on the rover I believe. But what of the video from before the rover was deployed, how was it transmitted?
I am sure there is an answer, but I don't know it, so I want to know what it is.
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All right, I have a bit of a question. I know that after Apollo 11 ,but before the J-class missions, they set up an S-band antenna on the lunar surface to transmit the colour TV signals. However, how did they transmit those (http://www.youtube.com/watch?v=YEEIJYrXn9s)missions (http://www.youtube.com/watch?v=IhXsjENGrk0) first steps than in colour?
I know I am missing something, but what?
Moreover, they didn't use such an antenna on the J-class missions but used the antenna on the rover I believe. But what of the video from before the rover was deployed, how was it transmitted?
I am sure there is an answer, but I don't know it, so I want to know what it is.
The first step wasn't in colour and it was a pretty crappy quality.
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Looks like colour to me, especially on the first.
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You're right, Apollos 12 and 14 deployed a "parasol" S-band antenna. Until it was set up, they used the smaller steerable S-band dish on the LM to send TV.
Apollo 15 also used the steerable until the rover was set up, the LCRU (Lunar Communications Relay Unit) was turned on and the camera moved from the LM to the rover. That's how we saw the rover being deployed.
A restraining pin on Apollo 16's steerable S-band antenna failed to release so there was no TV (and very scratchy audio through the omni antennas) until the rover was set up.
I forget whether Apollo 17 had video during the crew's initial descent to the surface.
The LM S-band transmitter had a 4-position antenna switch: Forward Omni, Aft Omni, Steerable, external (parasol). It could transmit either mode (PM/FM, with FM used for video) on any of the antennas and it would work if the link budget was adequate.
Apollo 11 also carried the parasol antenna but because of the short (2 hr) EVA they didn't want to spend time setting it up unless the TV picture quality through the steerable antenna was unacceptable. To give themselves the best chances for success, they arranged for the 64m Parkes radiotelescope in NSW Australia to receive TV, as famously (and not exactly accurately) depicted in the movie "The Dish". And of course it worked.
So the parasol antenna was actually not essential for TV. It really had two other purposes: to provide some extra margin if a large ground antenna were not available for some reason, and to let the LM conserve battery power by turning off its S-band power amplifier and running "barefoot" as we hams put it. This was the real reason it was used on Apollos 12 and 14; battery power was much more important given their longer stays, and of course they had the extra time needed during the EVAs to erect it.
The parasol antenna was almost not worth it. Its cable was so long, and the operating frequency so high, that (from memory) only 1/8 of the transmitter's power actually made it to the antenna; 7/8 was wasted as heat. I.e., the loss was 9 dB. In those days there was no choice because the S-band amplifier was too big to mount on the antenna. Today we could easily do that, and also operate on a much higher frequency band that could carry much more data with the same power. Or we could use an optical link as was recently demonstrated from the moon on the LADEE mission. Imagine the kind of TV coverage we could have now from a human lunar mission...
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Looks like colour to me, especially on the first.
It's not. But it's tough to tell given how colourless the Moon is.
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Looks like colour to me, especially on the first.
It's not. But it's tough to tell given how colourless the Moon is.
Apollo 12 and 14 were definitely colour throughout, even before the big parasol antenna was put up. You can clearly see the gold of the LM legs in that video, and the red stripes on Shepard's suit.
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The key was the camera. The camera itself was black and white, but the ones from Apollo 12 onwards had a filter wheel that rotated frames through the primary colours. On the ground, three frames were combined to produce colour.
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Dwight's really the go-to guy for this one, but I think that, as a result from data gathered on AS-11, they found that the steerable would handle enough bandwidth for color.
Pete Conrad's "Whopee!" was in color.
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The Apollo color camera used no more bandwidth than ordinary black-and-white broadcast TV, because that's what they used: an ordinary NTSC black-and-white camera. Color was provided by spinning a color wheel in front of the camera so that each successive field (1/60 sec) was in a separate color. The scheme was called field-sequential color.
The Apollo 11 lunar surface camera wasn't just black and white, it was also slow-scan at only 10 frames/sec and with fewer lines per frame.
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Thank you everyone for your replies. :)
Always neat to learn something new.
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One point regardsing possible color on the lunar surface for Apollo 11 was recounted in "Live TV From the Moon" (p. 131)
"A contingency plan submitted by Westinghouse contained a proposal and study to modify and adapt the slow scan black-and-white lunar TV camera to provide a color image. It consisted of a mechanical device placed over the TV camera lens it which was basically an external version of the color wheel in the color Westinghouse cameras. A reference black segment was incorporated on the wheel to allow calibration as the sequence started. Three quadrants of the primary colors red, green and blue were automatically moved into position when the starter sequence was started by the astronaut. The filters were moved by way of a spring loaded rotating wheel mechanism. Each filter would rotate into position resulting in a sequential color signal being sent via the slow scan TV camera to Earth. The movement and dwell time of each filter was 4.8 seconds with the end color, blue being the one the mechanism rested on until the rotation sequence was started again.
This color sequence would be reconstituted on the ground via a Polaroid camera with a color filter placed over its lens. A decoder system was put in place to match the ground color wheel with the
appropriate incoming color. The three color frames would then be exposed on top of one another in the Polaroid camera with the resulting photograph being a full colour image! This mechanical system was devised as a back up to the color film cameras in case of malfunction, or in a worst case scenario, if the astronauts became stranded on the moon, they could at least return immediate color images of the surface features. Despite having a weight of only 1.5 pounds, the idea was never adopted by NASA."
A pity that was never incorporated in the mission plan to at least send immediate color images back to an eager viewing public. Regarding plans for color TV on the lunar surface, this is from pages 161 to 162:
"The mission of Apollo 12, although being the second lunar landing, was also one that contained a number of “firsts”. Building upon the achievements of Apollo 11, the mission was to attempt a more scientific assignment, aided by the pinpoint landing at Surveyor crater, the site where the unmanned Surveyor III probe had landed in 1967. Realising the potential for generating huge public interest in the moonwalks, a color TV camera became one of the new things to appear on the mission plans. George Low in a June 26 memo to Sam Phillips announced that there was hurried research into the feasibility of implementing a color television camera into the lunar surface items for the Apollo 12 landing. He mentioned that even from a color camera, the black-and-white image was notably of better quality. He cautioned however, that at such a late date, “…it would be best not to plan on using this system for a September Apollo 12 flight.” However, if the flight moved to a November launch date, the camera was ready to fly. With two lunar EVAs planned, the use of a color TV camera was a bold step in showing the world just how the surface of the moon looked, live and in color.
A series of tests were performed on October 19, 1969 to evaluate whether the LM communication could handle the color signal without any hindrance to its communications system. The tests were carried out via the Merritt Island Facility and relayed to the Manned Spaceflight Center in Houston where appraisal was made of the S-Band signal in its lunar surface EVA configuration. The conclusion was not optimistic for the color TV camera. Despite revealing no adverse effects on the entire data package contained in the transmitted S-Band signal, there was notable picture
disturbance caused internally by the camera. A pattern of horizontal lines which were a by-product of the color wheel motor and the 100 foot long video cable, which would be connected to the camera as it was activated for the first time, were evident on the images, rendering the quality completely unacceptable. The recommendation was made for a series of filters to minimize the annoying lines, and to assist in better overall signal quality. With the possibility of not having color television beamed from the lunar surface, urgent modifications were recommended to the TV camera to eliminate the problem
of the horizontal line interference as quickly as possible."
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I sure wish we could go back to the moon with modern cameras and digital communications...
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Don't you mean Area 51? Oh. Wait...
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Cool! I wonder if it would have used the low frame rate but high res mode for the Apollo 11 colour slide show?
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Yep that is exactly what it was intended for. It could have worked in the 320 line mode as well, but was predominantly for backup in case the color hassleblads failed.
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Yep that is exactly what it was intended for. It could have worked in the 320 line mode as well, but was predominantly for backup in case the color hassleblads failed.
Heh, I just love some of the surprisingly low-tech solutions that Apollo had. It's really too bad that the slow scan tapes were lost, as they really show significantly better detail and contrast, but the kinescope did its job.
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This is the document regarding the adapter - just like you say, very low tech but very effective.
https://dl.dropboxusercontent.com/u/4960558/A11_color_test.pdf
The top color picture is from the adapter method and the bottom is a regular 35mm reference color photo.
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This is the document regarding the adapter - just like you say, very low tech but very effective.
https://dl.dropboxusercontent.com/u/4960558/A11_color_test.pdf
The top color picture is from the adapter method and the bottom is a regular 35mm reference color photo.
Not bad given the circumstances, and if the choice was that or nothing . . .
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Sure, not bad for stills. It's when things move that stuff starts getting weird.
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Sure, not bad for stills. It's when things move that stuff starts getting weird.
True that, though fast enough movement could also do weird to the sequential colour camera that was used as well.
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And there, raven, is the very reason why I started researching "Live TV From the Moon" and "Live TV From Orbit": I could not get my head around how they got color from the lunar surface, and why the images looked confetti-like during fast motion.
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And there, raven, is the very reason why I started researching "Live TV From the Moon" and "Live TV From Orbit": I could not get my head around how they got color from the lunar surface, and why the images looked confetti-like during fast motion.
As I said to a conspiracy theorist (Kartraceone) who complained that I had an answer to everything, "That's because there is an answer!"
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Yes, every question has an answer. The problem with the CT's is that the answers aren't what, as Steve Shives said, in their "f***ing warped, dark, paranoid, broken psyche" think they are.
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Imagine, if you will, the day a CT/HB listens to your explanation and calmly says, "Hey, you know that is an entirely plausible explanation which makes alot more sense than anything I've read from a consiparcy believer to date!"
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Perhaps I am just cynical, but I imagine world peace will come first.
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And with that note, an LP from 1959 called "How to Speak Hip" by Del Close and John Brent is worth picking up. Hilarious if you can dig it without becomming a juice-head, man!
http://en.wikipedia.org/wiki/How_to_Speak_Hip
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Buying a record to learn to speak hip is just so square.