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The Lunar Roving Vechicle (LRV), also known as Moon Buggy, was used as a form of transportation on the surface of the Moon during the Apollo program.

enter image description here

What system did the astronauts use for navigation purposes whilst in the LRV?

I assume the astronauts lost sight of the Lunar Module (LM) and they had maps with them and could have used an inertial navigation system to produce selenographic coordinates telling them where they are on the surface of the Moon.

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    $\begingroup$ From what I know about the surface of the moon, I doubt they would have problems finding their way back to the LM - just follow the tracks in the dust. $\endgroup$
    – Steve
    Dec 22, 2015 at 20:27
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    $\begingroup$ Just a heads up that the photo is a composite in which the Earth is far too big. $\endgroup$ Jan 9, 2018 at 20:35
  • $\begingroup$ @user2705196 ... the light direction on the lunar surface in incompatible with the phase of Earth as well. SE convention is to give source credit for graphics. $\endgroup$
    – Woody
    Dec 18, 2023 at 0:38

3 Answers 3

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The navigation system used a combination of magnetic pickups in the wheels (to count how many turns each one has taken) and a directional gyro. This allowed both turn angles and distances travelled to be calculated on board.

See this section of the manual, section 1.3.7 "Drive Control Electronics" (page 5 onwards.)

Also page 18 of the above link shows the instrument panel, which included a heading indicator and distance back to the LM.

More sections of the manual can be downloaded from the Apollo Lunar Surface Journal.

A Performance Review was written, which includes more technical information and traverse plots for all trips made.

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    $\begingroup$ Ha ha! Yes this is a funny problem @dotancohen $\endgroup$
    – spk578
    Dec 23, 2015 at 10:11
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    $\begingroup$ Your LRV navigation answer is not correct. There was no use of magnetic pickups or "turn angles". Please refer to the excellent 2012 Haynes “Lunar Rover Owners’ Workshop Manual”, whose authors (Christopher Riley, David Woods,and Phillip Dolling) I helped with writing. That book tells you everything you need to know about those wonderful extra-terrestrial vehicles and how navigation was accomplished. The Library of Congress number for that book is: 2012940365. Best wishes, Ron Creel $\endgroup$
    – Ron Creel
    May 15, 2018 at 23:53
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Well if they did slip their navigation they can follow their tracks back to the LM. They planned for this in case of total breakdown, how much more for nav error.

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    $\begingroup$ Not sure why someone voted this down - the Apollo 17 crew have referred to looking for their own tracks at one or two points as a check on their position. $\endgroup$
    – Andy
    Dec 23, 2015 at 7:33
  • $\begingroup$ @Andy it's likely due to the lack of source, even your comment cites something without a source ;). $\endgroup$ Jul 9, 2018 at 16:34
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There were "odometers" on all 4 wheels, which did use magnetic sensors to generate 9 pulses for each wheel's revolution. That pulse data was used for calculating distance traveled and speed based on pulses from a single wheel. There were no "turn angles" generated.

The directional gyro, in combination with use of sun attitude devices (pitch and roll angle of the vehicle along with sun attitude using a shadow device), provided the needed data for initialization and updating of the Rover navigation system.

I still refer y'all to the identified book for a more complete answer and description of the rover navigation system and how it worked very well on the Moon- just please forget the "turn angles", which did not exist.

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    $\begingroup$ To clarify--are you saying the "turn angles" aren't generated for odometry? I understood them, in Andy's answer, as coming from the DG and having something to do with the heading back to the LM. $\endgroup$
    – Erin Anne
    May 16, 2018 at 5:26

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