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Author
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Topic: Apollo S-band antenna on the lunar surface
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Explorer1
Member Posts: 180
From: Los Angeles, CA, USA
Registered: Apr 2019
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posted 04-08-2020 04:57 AM
  
On Apollo 12, Pete Conrad and Alan Bean erected a high gain dish antenna at their landing site. I believe this was done for the television camera but the sensor in the camera was damaged and so there were no television images. A similar antenna was erected during the Apollo 14 mission, and no doubt one would have been erected on the Apollo 13 mission as well. I don't recall ever seeing such an antenna erected on the Apollo 15, 16 and 17 missions. Is this correct? And also, such an antenna was suppose to be erected on Apollo 11, but they never did it. Why did they cancel deploying the antenna and was the cancellation far enough in advance that the antenna was not stored aboard the lunar module? How much did that affect the television transmissions that were received on Earth of the crew at the landing site? |
Space Cadet Carl
Member Posts: 225
From: Lake Orion, Michigan
Registered: Feb 2006
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posted 04-08-2020 05:47 AM
You asked several great questions. The one thing I do know is the small, pointable dish on the Lunar Rover had a small alignment sight installed on it, and that small dish provided what seemed to be ample enough gain to deliver a great color TV signal back to Earth. Also, I believe Apollo 15, 16 and 17 used the largest 120 foot diameter ground station dishes we had to receive signals. The earlier landings like Apollo 11 used smaller dishes, like the 85 foot dish at Goldstone, California. |
Jim Behling
Member Posts: 1488
From: Cape Canaveral, FL
Registered: Mar 2010
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posted 04-08-2020 07:03 AM
quote:
Originally posted by Explorer1:
I don't recall ever seeing such an antenna erected on the Apollo 15, 16 and 17 missions. Is this correct?
The rover antenna took its place.Apollo 11 had too short of time to use it and the decision was after it was stowed. It's obvious that there wasn't an effect. |
nasamad
Member Posts: 2141
From: Essex, UK
Registered: Jul 2001
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posted 04-08-2020 11:10 AM
The "One Small Step" page of the Apollo 11 Lunar Surface Journal discusses the decision not to deploy the high gain antenna during the EVA. Armstrong - "We wanted to make sure the picture was adequate so that we didn't have to take the time to unpack that (S-band) antenna and unfold it. It was pretty good size. I'd say it's maybe eight feet across."This was the S-Band antenna that was deployed on 12 and 14. On Apollo 11, it was stowed in LM Quad I to the right of the ladder. Journal Contributor Bill Wood writes, "The plan was to only ask for deployment of the erectable S-band antenna if the signal through the LM high-gain antenna was not good enough. The decision to carry the dish was made several months before the mission when there was concern that it might not be possible to handle the EVA through the Goldstone DSS-14 antenna due to a conflict with an on-going DSN (Deep Space Network) mission. However, that proved not to be a limitation. Of course, if the EVA occurred over Spain or if either DSS-14 nor Parkes was available, the erectable dish would have been used. Neil Armstrong was aware of this and made a point to check the received TV quality so he would know whether or not he would need to unstow the dish. |
Explorer1
Member Posts: 180
From: Los Angeles, CA, USA
Registered: Apr 2019
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posted 04-09-2020 08:03 AM
I really appreciate all of these great responses. Thank you. | |
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