Eagle Lander 3d (FAQ)

an 'Apollo Lander' simulation for Windows

Eagle Lander 3-d Click here to visit the publisher's site
Screen shot: An actual exterior view of the LM descending to the moon in this simulation
IntroductionUsing the Simulation

Installing the Simulation (v2.1.2)

Apollo Enthusiast Area

Introduction

'Eagle Lander 3d' Simulation Features

'Eagle Lander 3d' Activities for Newbies

keystroke examples
nomenclature actual windows key
3 keyboard 3
NPAD-3 numeric keypad 3
F3 F3

Activity 1a (free): Locating Instruments and Switches on Your First Mission

"Free Version" Caveat: "Apollo-11 Short" is the only mission enabled -and- the DSKY keypad is disabled.
  1. After starting the program from Windows, select the following choices then click the "Continue" button
    Startup Window: Virtual Cockpit 2
    Mission: Apollo 11
    Flight: Short Flight P66 (will work with free version)
  2. When the program finishes initializing, click Replay: Start then hit P to pause the simulation
  3. Use the following keys to look around the cabin or get help
    F F F F F F F F F F F F
    1 2 3 4 5 6 7 8 9 A B C

    1 2 3 4 5 6 7 8 9 0

    Q W E
      |
    A-S-D
      |
    Z X C
    basic keystrokes
    Key Function
    F1 General Help
    caveat: some commands (like "Engine Shutdown" and "Plant Flag"
    to only name two) are wrong. Improved help can be viewed by
    clicking the HELP button just after you start the app
    F2 AGC/DSKY Program Help (for whatever AGC program is running)
    1 VCV-1: Look out the commander's window
    2 VCV-2: See commander's window & center console
    3 VCV-3: Commander's view of DSKY
    4 Cockpit View 1: Left Window / FDAI Ball - DSKY
    5 Cockpit View 2: Left Window / FDAI Ball - DSKY (Faded)
    6 Cockpit View 3: Left Window / Totally Transparent Equipment
    7-8 Spot Views 1-2
    9 Ground View (watch the LM from the surface of the Moon)
    0 EVA view (start an EVA and descend the ladder)
    SHIFT-G toggle the PGNS (primary guidance and navigation system) switch
    T toggle the THROTTLE switch
      Cockpit Spot View EVA
    Q  Move Down
    		  Zoom In  
    W Zoom Into The Panel Rotate Up Walk Forward
    E Move Up
    		 Zoom Out  
    A Move Left
    		 Rotate Left  
    S    - Reset  
    D Move Right
    		 Rotate Right  
    X Zoom Out From The Panel Rotate Down Walk Backward
    Arrows Tilt: Up-Down-Left-Right   Tilt: Up-Down
    Turn: Left-Right
  4. Hit 3 to look down at the DSKY (Display and Keyboard). Notice you are running program 66 (PROG 66).
    1. Hit F2 to get P66 specific help.
      (this is one of the neatest features built into this simulation; whenever we punch "F2" we will get specific help for the currently running AGC program)
    2. Notice that the next program after this one is P68.
    3. Hit F2 again, or ESC, to clear the help and return to the DSKY.
  5. Press and hold E to elevate UP so you can at the switch panel above the DSKY. (alternatively, hold-down the up arrow key if using a full 105-key keyboard)
  6. Locate the PGNS switch and notice that it is set to ATT HOLD
    Optional: Repeatedly hit SHIFT-G until you see PGNS-Auto at the top of the screen. You will see and hear the switch changing position.
  7. Hit 2 and look at the switches under the gyro display
  8. Locate the Throttle switch labeled THR CONTROL and notice it is set to auto.
    Optional: repeatedly hit T until you see Throttle=Auto at the top of the screen. You will see and hear the switch changing position.
  9. Here is a short list of Windows-Keys required to operate LM-Switches. Caveat: these key assignments can be changed by editing these two files: "JoyAssign.ini" (which only affects keys used when a Joystick is active) and "KeyboardOnly.ini". Operating these keys should result in hearing a click and seeing the key move.

    Flight Controls (from official documentation)
    With Joystick Keyboard Only Command
    None NPAD4 Roll Left
    None NPAD6 Roll Right
    None NPAD8 Pitch Down
    None NPAD2 Pitch Up
    NPAD1 NPAD1 Yaw Left
    NPAD3 NPAD3 Yaw Right
    F8 F8 Translate Forward (+Z)
    F7 F7 Translate Backwards (-Z)
    F9 F9 Translate Left (-Y)
    F10 F10 Translate Right (+Y)
    F12 F12 Translate Up (+X)
    F11 F11 Translate Down (-X)

    Cockpit Switches (from official documentation)
    With Joystick Keyboard Only Command
    + + Rate of Descent (ROD) Up (see Vista Caveat below)
    = = Rate of Descent (ROD) Up (see Vista Caveat below)
    R R Rate Scale Toggle
    SHIFT+D SHIFT+D Deadband Toggle
    SHIFT+R SHIFT+R Roll Mode Toggle
    SHIFT+P SHIFT+P Pitch Mode Toggle
    SHIFT+Y SHIFT+Y Yaw Mode Toggle
    SHIFT+A SHIFT+A AGS Toggle
    SHIFT+P SHIFT+P PGNS Toggle (Primary Guidance and Navigation System)
    H H X-Pointer Toggle
    T T Man/Aut ThrottleToggle
  10. When you're finished looking around, hit key 5 or 2 to change the view then hit P to un-pause the simulation and continue descent to the lunar surface.
  11. Optional Stuff (Post Landing)
    1. After landing, hit 3 to look at the DSKY
    2. Make sure the NumLock light on your keyboard is illuminated; if it is not, hit the NumLock key until it is
    3. On your numeric keypad you should enter V37EN68E* (Verb, NPAD-37, Enter, Noun, NPAD-68, Enter, NPAD-star) to complete the post landing procedures.
      Alternatively, you may click the DSKY buttons with your mouse to enter:
          VERB 37
          NOUN 68
          PROCEED
      DSKY Key DSKY Nomenclature Windows Key
      VERB V V
      NOUN N N
      ENTR E NPAD-enter
      0-9 0-9 NPAD-0 to NPAD-9
      PRO/ceed STAR NPAD-star
      RSET PERIOD NPAD-period
  12. Once you're on the surface, hit 0 (zero) to start an EVA
  13. Press either the left or right arrow keys until you are facing the back of the LM
  14. Press X to back out of the LM and descend the ladder
  15. Turn to the right and hit W to walk forward a few steps
  16. Hit F to plant the flag
  17. Hit Esc several times to end the simulation
        -OR-
    Jump down to activity-5 (Ascent From the Moon)

Activity 1b (free): Apollo-11 Lands in the Sea of Tranquility (with 1201 alarm)

  1. After starting the program from Windows, select the following choices then click the "Continue" button
    Startup Window: Virtual Cockpit 2
    Mission: Apollo 11
    Flight: Long Flight P64 (only works with registered version)
  2. When the sim finishes initializing, click Flight: Start then hit P to pause the simulation
  3. Repeatedly hit SHIFT-G until you see PGNS=Auto at the top of the screen. You will see and hear the switch changing position.
  4. Repeatedly hit T until you see Throttle=Auto at the top of the screen. You will see and hear the switch changing position.
  5. When you're finished looking around, keep looking at the DSKY while you hit P to continue the simulation
  6. Within 50 seconds the guidance computer will display a 1201 alarm so hit NPAD-period to reset the guidance computer
    (note: 1201 is an alarm indicating that the computer is overloaded with data coming from the rendezvous radar which is part of the abort guidance system)
  7. Now hit 1 to look out the window and enjoy the automated landing.
    optional...
  8. The computer would have taken the crew into a boulder field. When you are about 500 feet (what, no meters?) off the surface you'll need to repeatedly hit SHIFT-G until you see PGNS=Attitude-Hold then use and "=" (increase) or "-" (decrease) to throttle engine power so you can fly over the boulder field. Now you will use the joystick or numeric keypad to control the landing:
    Pitch - Roll - Yaw
      8       Pitch Down  
    4 5 6   Roll Left Center Roll Right
    1 2 3   Yaw Left Pitch Up Yaw Right
    Windows-Vista Caveat: there are two keyboard definition files
    1. KeyboardOnly.ini
      Rate Of Descent UP key=EQUALS (which is under the plus symbol)
      Rate of Descent DOWN key=MINUS
    2. KeyboardOnly IDE.ini
      Rate Of Descent UP key=O (oh)
      Rate of Descent DOWN key=I (eye)
    With Windows-Vista you will be probably be using file "KeyboardOnly.ini" but will find that the EQUALS key is not being recognized by EagleLander3d. Just edit this file like so:
    Rate Of Descent UP key=F12 (which is just above EQUALS)
    Rate of Descent DOWN key=F11 (which is just above MINUS)
  9. When you hear or see "contact light", hit K to kill the main engines
  10. hit 3 to look at the DSKY then use your keypad to enter V37EN68E* (Verb, NPAD-37, Enter, Noun, NPAD-68, Enter) followed by PRO/ceed (NPAD-star) to complete the post landing procedures. Alternatively, you may click these buttons with your mouse.
  11. Hit any key between 1 and 9 to look around
  12. Click here for ascent procedures

Activity 2 (licensed): Apollo-12 Lands in the Ocean of Storms (with EVA to Surveyor-3)

  1. After starting the program from Windows, select the following choices then click the "Continue" button
    Startup Window: Virtual Cockpit 2
    Mission: Apollo 12
    Flight: Short Flight P66 (only works with registered version)
  2. When the sim finishes initializing, click Replay: Start then sit back and watch the astronauts land Apollo 12 in the Ocean of Storms.
  3. Now hit 0 (ZERO) to begin an EVA.
  4. Press the left arrow key to rotate 180 degrees then press X so you can back out of the LM and crawl down the ladder.
  5. Hit the right arrow key a few times to turn to the right then hit W to walk forward a bit.
  6. Hit F to plant the flag (it will also be visible from the cockpit view by hitting 1. Hit 0 to go back to the EVA)
  7. Notice the crater on the port side of the LM containing Surveyor-3 which is 200 meters (650 feet) away.
    Note: Landing this close to Surveyor-3 is a spectacular example of engineering and navigation
  8. Press W to walk towards it. It will require about 2.5 minutes to get there.

Activity-3 (licensed): Apollo-15 Lands on Hadley Plain (with EVA to Hadley Rill)

  1. After starting the program from Windows, select the following choices then click the "Continue" button
    Startup Window: Virtual Cockpit 2
    Mission: Apollo 15
    Flight: Short Flight P66 (only works with registered version)
  2. When the sim finishes initializing, click Replay: Start then sit back and watch the astronauts land Apollo 15 on Hadley Plain.
  3. Now hit 0 (ZERO) to begin an EVA.
  4. Press the left arrow key to rotate 180 degrees then press X so you can back out of the LM and crawl down the ladder.
  5. Press your left arrow key to rotate another 180 degrees until the ladder is at your back. Make sure the shadow of the LM is directly in front of you.
    Note: please stop to consider the following planetary mechanics.
    1. Close your eyes and imagine a spinning Earth in front of your with the north pole at the top and the Sun to your right. The moon is behind the Earth.
    2. Since the Sun appears to move across Earth's sky from East to West, the Earth must be spinning West to East (or counter-clockwise as viewed from Earth's North pole).
    3. Apollo rockets were launch toward the East so the surface speed of the spinning spin Earth would be added to the rocket's velocity.
    4. Now imagine the same closed-eye view as before but slightly higher so you can now see the moon behind the Earth. When Apollo was launched toward the moon, it was sent on a figure-8 trajectory so the moon's gravity could more easily capture the space craft. Apollo was aimed at the left-hand side of the moon (or where it would be 3-days later), it then would travel around the backside, then would pop out on the right hand side of the moon as seen from Earth. So Apollo in orbit around the moon is in the opposite direction than Apollo's orbit around Earth. This means that Apollo landed on the moon coming out of the Moon's East with the Sun behind the LM. Since the LM begins the landing sequence with the ladder facing up, after pitch over the ladder will almost always point directly West. 
    5. Visit this site ( http://www.google.com/moon/ ) then zoom into the Apollo-15 landing sit. Notice that Hadley Rill is directly to the West.
  6. See the mountain slightly to the left of the top of the LM shadow? This mountain is on the other side of Hadley Rill.
  7. Press W to walk towards it. It will require about 30 minutes to get there.

Alternate variation: Why walk to Hadley Rill when you can fly there?

  1. After starting the program from Windows, select the following choices then click the "Continue" button
    Startup Window: Virtual Cockpit 2
    Mission: Apollo 15
    Flight: Short Flight P66 (only works with registered version)
  2. When the sim finishes initializing, click Flight: Start then hit P to pause the simulation
  3. Repeatedly hit SHIFT-G until you see PGNS=Auto at the top of the screen. You will see and hear the switch changing position.
  4. Repeatedly hit T until you see Throttle=Auto at the top of the screen. You will see and hear the switch changing position.
  5. Now  hit P to continue the simulation
  6. Fly until you hear the phrase LPD (landing position designator)
  7. Now hit P to pause the simulation
  8. hit 3 to look at the DSKY and notice that REGISTER ONE is displaying "99-55". This means you will land at the position associated with mark 55 on the LPD and you  have 99 seconds to tweak the PGNS
  9. hit 1 to look out the commander's window and look at mark 55 on the vertical red line etched on the window (known as the LPD or Landing Position Designator). Look through the marks corresponding to 55 and this is where the PGNS will take you). Hitting 8 will subtract 0.5 degrees while hitting 2 will have the opposite effect.
  10. Now hit 3 to look at the DSKY.
  11. Hit P to continue the simulation
  12. Hit PRO/ceed (NPAD-star) to accept.
  13. Hit NPAD-8 seventeen times which will force the PGNS to perform a longer landing (17 represents an 8.5 degree correction to LPD marking)
    1. You will not see these changes on the DSKY display
    2. Caveat: hitting the key eighteen times will cause to to land on the inside edge of Hadley Rill which is fun to watch from the Starboard-side exterior view (hit 8 then press A). You will be on a 30 degree descending slope.
  14. You are now a short walk from the edge of Hadley Rill

Another Variation: "How Low Are We? (compared to the mountains)" and "Lets Do an Abort"

  1. After starting the program from Windows, select the following choices then click the "Continue" button
    Startup Window: Virtual Cockpit 2
    Mission: Apollo 15
    Flight: Short Flight P66 (only works with registered version)
  2. When the sim finishes initializing, click Flight: Start then hit P to pause the simulation
  3. Hit 8 to go to Spot View 2
  4. Hold down A until you have rotated through 90 degrees. You are looking at a mountain top that is as high as we are. Yikes!
  5. Hold down A until you have rotated through 180 degrees. Wow, that mountain top is just as high.
  6. Hold down A until you have rotated through 90 degrees. You should now be looking at the back of the LM
  7. Now hit P to continue the simulation.
  8. Hit CTRL-A to abort the landing. The Descent Stage will now jettison.

Activity 4 (licensed): Ascent from the Moon

Caveat: In version 2.1.2 this section is a little flaky so you must follow theses instructions to the letter. Failure to do so will result in you hearing ascent audio but not seeing the associated video.

  1. While on the moon, hit 3 to look at the DSKY.
  2. Make sure the NumLock light on your keyboard is illuminated; if it is not, hit the NumLock key until it is
  3. If you've just landed on the moon then be sure to enter the post landing procedures by keying:
  4. The following information was derived (and slightly modified) from the official simulator documentation
  5. Prepare to start the Ascent Program by entering V37E12E. (I am guessing that NOUN is assumed after VERB because this key sequence produces the same results: V37EN12E)
  6. Hit PRO/ceed (NPAD-star) for the first time.
  7. Hit PRO/ceed (NPAD-star) for a second time.
  8. Hit PRO/ceed (NPAD-star) for a third time.
  9. At t-minus 35 seconds the DSKY display will blank out while AGC does intense final computations.
  10. At t-minus 29 seconds the DSKY display reappears and counts down to 5 seconds.
  11. You will hear the astronaut start counting down from 9 to 5.
  12. This step is very important - if you mess it up you'll hear ascent audio but won't see ascent video
  13. Quickly punch one of the following main keyboard keys:
  14. At t-minus zero, ignition occurs and the ascent stage will blast off. After a short vertical ascent, the LM pitches forward to begin its acceleration into lunar orbit. You can ride along for awhile but EL3D 2.1.2 does not take you all the way into lunar orbit. As you leave the scenery area you will see the moon but you are also flying into the dark side of the moon.

Activity 5 (licensed): Undocking / Docking with a CSM

  1. After starting the program from Windows, select the following choices then click the "Continue" button
    Startup Window: Virtual Cockpit 1
    Mission: Orbital
    Flight: CSM-LM Docked (only works with registered version)
  2. The Blue Danube is playing because the authors have a sense of humor and they want us to remember the rendezvous sequence in the movie 2001: A Space Odyssey when the Pan Am Clipper is docking with double-wheeled space station in Earth orbit
  3. When the sim finishes initializing, hit P to un-pause (is this a bug in the sim?)
  4. Hit 7 to move to Spot-View-1 (you are now above the docked CSM-LM looking down at the moon)
  5. Hit CTRL-D to undock
  6. Hit 2 to move to Virtual-Cockpit-2 (you'll be looking at the rendezvous and docking target)
    1. You may need to hit Q to move back from the alignment scope which will increase your field of view.
    2. Alternatively, hit W to move closer to the eyepiece.
  7. Wait 15-20 seconds, then hit NPAD-INSERT 15 times to stop your retreat (hit 4 then use the X-pointer display to get your velocity down to zero which is in the center of the display)
  8. Hit NPAD-INSERT 15 more times to re-dock with the CSM.
  9. Here are the translation keys for a full-size keyboard:

    On older "full size" keyboards this keypad sits between the main keypad and the numeric keypad
    INSERT HOME PAGE UP
    DELETE END PAGE DOWN
    UP
    LEFT DOWN RIGHT
    X+ Y+ Z+
    X- Y- Z-
         
         
    Note: at first glance, X-axis may seem to be the wrong label until you realize that you are looking out the top of the LM

    On newer "full size" keyboards this keypad sits between the main keypad and the numeric keypad
      INSERT BREAK
      HOME END
      DELETE PAGE UP
      PAGE DOWN
      UP  
    LEFT DOWN RIGHT
    X+ Y+
    Y+ Y-
    X- Z+
    Z-
       
       

  10. Here are the translation keys for an IBM Thinkpad (laptop)
     
    PrtSc ScrLk PAUSE
    F10 F11 F12
    INSERT HOME PAGE UP
    DELETE END PAGE DOWN
    X+ Y+ Z+
    X- Y- Z-

'Eagle Lander 3d' Links:

Windows-Vista Installation Problems (v2.1.2)

Windows-7

Windows-Vista Keyboard Problem
Windows-Vista Caveat: there are two keyboard definition files
  1. KeyboardOnly.ini
    Rate Of Descent UP key EQUALS (which is under the plus symbol)
    Rate of Descent DOWN key MINUS
  2. KeyboardOnly IDE.ini
    Rate Of Descent UP key O (oh)
    Rate of Descent DOWN key I (eye)
With Windows-Vista you will be probably be using file "KeyboardOnly.ini" but will find that the EQUALS key is not being recognized by EagleLander3d. Just edit this file like so:
Rate Of Descent UP key F12 (which is just above EQUALS)
Rate of Descent DOWN key F11 (which is just above MINUS)

2.1.5 (beta) News

v2.1.5 (beta-F) Features and Missions

Unofficial List of Technical Changes

Missions/Flights (fewer missions than v2.1.2)

'Eagle Lander 3d' Graphics Card Caveat

Graphics Technology Basics

'Eagle Lander 3d' Multi-core Caveat

Other Space Simulator Links:

The following resources are not required when using 'Eagle Lander 3d'.
This stuff is targeted at "Space Enthusiasts", "NASA Nerds" and "Guidance Geeks"

DSKY + AGC (Apollo Guidance Computer) General Information

Excerpt: The on-board Apollo Guidance Computer (AGC) was about 1 cubic foot with 2K of 16-bit RAM and 36K of hard-wired core-rope memory with copper wires threaded, or not threaded, through tiny magnetic cores. The 16-bit words were generally 14 data bits (or two op-codes), 1 sign bit, and 1 parity bit. The cycle time was 11.7 micro-seconds. Programming was done by using an assembler to build an interpreter. Scaling was fixed point fractional. An assembly language ADD-instruction took about 23.4 micro-seconds. The operating system featured a multi-programmed, priority/event driven asynchronous executive packed into 2K of memory." -- Apollo 11: 25 Years Later by Fred H. Martin, Intermetrics, Inc., July 1994

Introduction

Apollo Guidance Computer @ Wikipedia
One Giant Leap: The Apollo Guidance Computer @ Dr. Dobb's

NASA History

www.hq.nasa.gov/office/pao/History/computers/Part1.html Computers in Spaceflight: The NASA Experience
www.hq.nasa.gov/office/pao/History/ap15fj Apollo 15
www.hq.nasa.gov/office/pao/History/computers/Ch2-5.html Apollo guidance computer: Hardware

Apollo Lunar Surface Journal

Apollo Glossary  
Apollo-11 Technical Air-to-Ground Voice Transcription  
Apollo-11 Lunar Landing Information includes information about "413 is in" which relates to AGS (Abort Guidance System)
Apollo-12 EVA Voice Transcription  

Non-NASA Sources

apollotribute2.blogspot.com A Tribute to Apollo (Part 2) Including Apollo Star Charts
www.taoyue.com/explore/orbiter.html Landing on the Moon - The Orbiter Space Simulator: An Appreciation
www.clavius.org Debunked Conspiracy Theories
www.clavius.org/techcomp.html Debunked Computer Technology Myths

DSKY + AGC (Apollo Guidance Computer) Technical Information

Note: sometimes AGC (Apollo Guidance Computer) is referred to as AFC (Apollo Flight Computer)

history.nasa.gov  
history.nasa.gov/computers/Ch2-1.html The need for an on-board computer
history.nasa.gov/computers/Ch2-2.html MIT chosen as hardware and software contractor
history.nasa.gov/computers/Ch2-3.html The Apollo computer systems
history.nasa.gov/computers/Ch2-4.html Evolution of the hardware: Old technology versus new block I and Block I designs
history.nasa.gov/computers/Ch2-5.html The Apollo guidance computer: Hardware
history.nasa.gov/computers/Ch2-6.html The Apollo guidance computer: Software
history.nasa.gov/computers/Ch2-7.html Using the AGC
history.nasa.gov/computers/Ch2-8.html The Abort Guidance System
history.nasa.gov/computers/Ch2-9.html Lessons Learned
https://history.nasa.gov/afj/ Apollo Flight Journal (entry point to individual flights)
history.nasa.gov/afj/compessay.html Apollo Flight Journal (includes a table of program numbers like P64 + P66)
history.nasa.gov/alsj/a12/a12.landing.html Apollo 12 EVA to Surveyor-3 - this document claims it's less than 400 f (122 m) away from the LM
nssdc.gsfc.nasa.gov/planetary/lunar/surveyor3data.html Surveyor-3 mission information
ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/
 19790076715_1979076715.pdf		 Apollo Guidance Computer (Raytheon) April, 1963
ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/
 19780070361_1978070361.pdf		 Apollo Guidance and Navigation (MIT Instrumentation Lab) August 1964
ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/
 19740072134_1974072134.pdf		 Apollo Guidance and Navigation (MIT Instrumentation Lab) Eldon C Hall - May,1963
hrst.mit.edu/hrs/apollo/public/index.htm more info from M.I.T.
www.hq.nasa.gov/office/pao/History/computers/contents.html Computers in Spaceflight: The NASA Experience
www.ibiblio.org/apollo/ Virtual AGC and AGS
www.ibiblio.org/apollo/yaDSKY.html Virtual DSKY
www.ibiblio.org/apollo/links.html Virtual AGC and AGS Links
ed-thelen.org/comp-hist/vs-mit-apollo-guidance.html M.I.T. Apollo Guidance Computer
www.doneyles.com/LM/Tales.html Tales From the Lunar Module Guidance Computer (by Don Eyles)
www.apollosaturn.com/Lmnr/contents.htm  
apollo.spaceborn.dk  
www.hq.nasa.gov/alsj/a11/a11.1201-fm.html
by Peter Adler and Don Eyles		 includes info about program alarms 1201 and 1202
comment: pin-headed reporters will have you believe that someone had mis-programmed the computer (AGC). This notion is completely wrong. In fact, the AGC was truly fault-tolerant and continued to function even though it was too busy to process all the incoming information. These alarms basically mean "I am too busy to do all you are asking of me so I'm only go to pay attention to the important stuff". To make matters worse, many people, including Apollo astronauts, were not provided with a correct understanding of the Rendezvous Radar mode switch which has these three labels: AUTO TRACK, SLEW, and LGC. Everyone thought that whenever the switch was not set to LGC, it was connected to the Abort Guidance Computer. Fact: the AGC was overloaded even when LGC was not selected because of a hardware interface problem between the AGC and the Grumman manufactured Rendezvous Radar. Both systems were powered by individual A.C. power supplies running at 800 Hz which where not synchronized to each other. This problem had been identified by many people before Apollo 11 but had slipped through the cracks. On top of that, the quick fix suggested before lunar ascent was to depower the Rendezvous Radar which kept it quiescent (unable to interrupt the AGC) so this is proof that Buzz Aldrin did not cause the 1201-1202 affair.
astro.uni-tuebingen.de/~wilms/computers/apollo.html  

LGC Program Codes

Some Recommended "Apollo Book" Resources

'Eagle Lander 3d' Author's (Ron Monsen) Personal Sites

'Eagle Lander 3d' was written by Ron Monsen (an American living and working in Dhahran, Saudi Arabia)

Other Links

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Neil Rieck
Kitchener - Waterloo - Cambridge, Ontario, Canada.