A Space & astronomy forum. SpaceBanter.com

Go Back   Home » SpaceBanter.com forum » Space Science » History
Site Map Home Authors List Search Today's Posts Mark Forums Read Web Partners

LM Rendezvous Radar



 
 
Thread Tools Display Modes
  #1  
Old September 4th 12, 05:19 PM posted to sci.space.history
David Lesher
external usenet poster
 
Posts: 198
Default LM Rendezvous Radar

So the LM had a rendezvous radar & the CSM a transponder. I never
really grokked why.

The LM was under insane weight limits, they were shaving heads off
bolts, etc. Why was the heavy radar on it, and not the CSM?

I know that in theory the LM was supposed to find & dock with a
passive CSM but:

a) Why was that ISTR that Plan B has the CSM docking with the LM
if it/its crew was unable to take the lead. The probe was in the
CSM hatch, could be removed by the CSM pilot, etc.

b) Even normally, I'd think that a telemetry scheme so that the LM
got radar data via existing paths would have weighed far less.

c) And with one radar, there'd have been no 1201's.....




--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433
  #2  
Old September 4th 12, 07:29 PM posted to sci.space.history
Jan Philips
external usenet poster
 
Posts: 54
Default LM Rendezvous Radar

On Tue, 4 Sep 2012 16:19:52 +0000 (UTC), David Lesher
wrote:

c) And with one radar, there'd have been no 1201's.....


I think Buzz said that he left the rendezvous radar on when it was
supposed to be off.
  #3  
Old September 4th 12, 08:03 PM posted to sci.space.history
Greg \(Strider\) Moore
external usenet poster
 
Posts: 790
Default LM Rendezvous Radar

"David Lesher" wrote in message ...

So the LM had a rendezvous radar & the CSM a transponder. I never
really grokked why.

The LM was under insane weight limits, they were shaving heads off
bolts, etc. Why was the heavy radar on it, and not the CSM?

I know that in theory the LM was supposed to find & dock with a
passive CSM but:


Completely guessing:

It simplifies the search problem. They had a pretty good idea of where the
CSM was, but not necessarily where the LM would be.

And they probably had the electronics perform double-duty with the landing
radar.



a) Why was that ISTR that Plan B has the CSM docking with the LM
if it/its crew was unable to take the lead. The probe was in the
CSM hatch, could be removed by the CSM pilot, etc.

b) Even normally, I'd think that a telemetry scheme so that the LM
got radar data via existing paths would have weighed far less.

c) And with one radar, there'd have been no 1201's.....





--
Greg D. Moore http://greenmountainsoftware.wordpress.com/
CEO QuiCR: Quick, Crowdsourced Responses. http://www.quicr.net

  #4  
Old September 4th 12, 08:42 PM posted to sci.space.history
David Lesher
external usenet poster
 
Posts: 198
Default LM Rendezvous Radar

"Greg \(Strider\) Moore" writes:

The LM was under insane weight limits, they were shaving heads off
bolts, etc. Why was the heavy radar on it, and not the CSM?


Completely guessing:


It simplifies the search problem. They had a pretty good idea of where the
CSM was, but not necessarily where the LM would be.


And they probably had the electronics perform double-duty with the landing
radar.


No on the 2nd part.... See http://www.hq.nasa.gov/alsj/alsj-LMRadars.html
--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433
  #5  
Old September 8th 12, 02:54 AM posted to sci.space.history
Obviousman
external usenet poster
 
Posts: 67
Default LM Rendezvous Radar

The radar was on, as per the checklist. It was left on in case of an abort.

The most accurate description of what happened with the alarms and the
radar is he

http://www.doneyles.com/LM/Tales.html

On 5/09/2012 04:29, Jan Philips wrote:
On Tue, 4 Sep 2012 16:19:52 +0000 (UTC), David Lesher
wrote:

c) And with one radar, there'd have been no 1201's.....


I think Buzz said that he left the rendezvous radar on when it was
supposed to be off.


  #6  
Old September 8th 12, 03:12 AM posted to sci.space.history
Jan Philips
external usenet poster
 
Posts: 54
Default LM Rendezvous Radar

On Sat, 08 Sep 2012 11:54:23 +1000, Obviousman
wrote:

The radar was on, as per the checklist. It was left on in case of an abort.


Hmm. A couple of weeks ago I saw an interview with Buzz in which he
said that the rendezvous radar was on when it didn't need to be. He
said that he wanted to have it on in case of an abort, implying that
it was not standard.
  #7  
Old September 8th 12, 04:39 AM posted to sci.space.history
Jan Philips
external usenet poster
 
Posts: 54
Default LM Rendezvous Radar

On Sat, 08 Sep 2012 11:54:23 +1000, Obviousman
wrote:

The radar was on, as per the checklist. It was left on in case of an abort.


Why didn't the 1202 and 1201 alarms happen on Apollo 10?
  #8  
Old September 8th 12, 03:11 PM posted to sci.space.history
Jan Philips
external usenet poster
 
Posts: 54
Default LM Rendezvous Radar

On Sat, 08 Sep 2012 11:54:23 +1000, Obviousman
wrote:

The radar was on, as per the checklist. It was left on in case of an abort.


"How Apollo Flew to the Moon", page 253 says "The program alarms were
caused by a procedureal error that had left the rendezvous radar in a
mode that sent false information to the computer."

It isn't exactly clear to me whether the astronauts made an error
following the procedures, or the list of procedures was wrong. But it
sounds to me like they made an error following the procedures.
  #9  
Old September 10th 12, 02:14 PM posted to sci.space.history
GordonD
external usenet poster
 
Posts: 151
Default LM Rendezvous Radar

"Jan Philips" wrote in message
...
On Sat, 08 Sep 2012 11:54:23 +1000, Obviousman
wrote:

The radar was on, as per the checklist. It was left on in case of an
abort.


Why didn't the 1202 and 1201 alarms happen on Apollo 10?



Because they didn't do PDI.
--
Gordon Davie
Edinburgh, Scotland

"Slipped the surly bonds of Earth...to touch the face of God."

  #10  
Old September 10th 12, 03:49 PM posted to sci.space.history
Jan Philips
external usenet poster
 
Posts: 54
Default LM Rendezvous Radar

On Mon, 10 Sep 2012 14:14:29 +0100, "GordonD"
wrote:

Why didn't the 1202 and 1201 alarms happen on Apollo 10?



Because they didn't do PDI.


OK. I thought Apollo 10 was a full dress rehersal, but you're right.
 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
X37B to rendezvous with ISS.... David Spain Policy 14 September 16th 10 12:06 AM
Rendezvous with Rama Maurice W UK Astronomy 4 March 18th 07 05:24 PM
It's May 25: Just Another Day, or Rendezvous with Doom? Double-A Misc 3 May 25th 06 12:44 PM
Space Based Radar, FIA/radar, redundancy? Allen Thomson Policy 2 April 22nd 04 05:19 PM
Rendezvous with Rama Testing Astronomy Misc 7 March 27th 04 07:59 PM


All times are GMT +1. The time now is 02:11 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 SpaceBanter.com.
The comments are property of their posters.