Author Topic: Were the Lunar Rovers faked?  (Read 280845 times)

Offline JayUtah

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Re: Were the rovers ever designed for one astronaut?
« Reply #315 on: March 26, 2013, 12:12:46 PM »
Anywho, why do you need two Rover threads?

Because everyone knows the rover can't balance on just one thread.
"Facts are stubborn things." --John Adams

Offline Echnaton

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Re: Were the Lunar Rovers faked?
« Reply #316 on: March 26, 2013, 12:13:11 PM »
You people seem to have a problem comprehending that it is not me who is saying it can't be sat on here on earth, it is something which often comes up in official NASA documents. I am saying it is a load of rubbish and I am glad many of you seem to agree.

Myth busted?

Are you just left with arguing whether it could be sat upon on earth?  Whether you have some NASA PR document that says it couldn't is really irrelevant, just give it up because that doesn't matter.  All that is important is weather the LRV could operate on the moon, and you have yet to make any case aside from irrelevant comparisons to terrestrial circumstances and vehicles.  If you want to demonstrate that the LRV could not operate on the moon, then show us why it could not operate on the moon.  It is a pretty simple request although one whose answer requires a great deal of knowledge about the environment and considerable engineering skills. 

Until you are able to demonstrate those attributes, why should we take you seriously?  And I'll reiterate the earlier question that you have dodged, where was the LRV footage made?  I'll add another question, if the rovers were incapable of operating on the moon, which of the Apollo missions do you think were faked and which were real?  Please include the reasons for your answers.
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Offline Echnaton

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Re: Were the rovers ever designed for one astronaut?
« Reply #317 on: March 26, 2013, 12:17:35 PM »
...the rovers with one astronaut are horribly unbalanced....

Still begging the question are we?
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Offline gillianren

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Re: Were the Lunar Rovers faked?
« Reply #318 on: March 26, 2013, 12:39:48 PM »
You people seem to have a problem comprehending that it is not me who is saying it can't be sat on here on earth, it is something which often comes up in official NASA documents. I am saying it is a load of rubbish and I am glad many of you seem to agree.

Okay, you've provided one.  Which isn't "often."  But even leaving that aside, do you know who wrote the line?  Not just "a NASA document."  I mean a specific person and their specific qualifications to say anything relevant.  The people writing press releases were not engineers, and it's what the engineers said that mattered more.  It's, and I am a bit tired of repeating this, the numbers that matter.
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Offline JayUtah

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Re: Were the rovers ever designed for one astronaut?
« Reply #319 on: March 26, 2013, 12:59:33 PM »
...I find it interesting that I have not seen any guidelines or testing done for one astronaut on board.

I believe that you have not yet seen them.  There is a vast amount of material easily available on the lunar rover.  It takes the average person several weeks to read it all carefully.  It's not exciting reading, but then again most engineering documents are not meant to be entertaining.  And with the NTRS down until further notice, alternate sources must be sought out.

But consider this.  Given the characterization of what you have already read, which likely goes into meticulous detail, what is the most likely explanation for your inability yet to find documentation for single-occupant testing:  (a) the tests were never done, or (b) you just haven't run across them yet?

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As I pointed out throughout the thread, the rovers with one astronaut are horribly unbalanced...

Asserted, but no quantitative argument provided.  Begging the question does not convince me.

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The problem with this is that it does indeed appear as though only one astronaut shifts the CoG outside the acceptable limits...

By what argument and computation?  It's not necessarily inappropriate to anticipate your critics' objections and attempt to account for them.  It borders on the straw-man fallacy, but not in this case.  However if you anticipate that we will make a certain argument, and it is a quantitative argument according to a physical model, you cannot just handwave away the objection.  If you claim the LRV would be unacceptably unstable when operated by one person, you bear the burden to provide the computations that support that conclusion.

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In particular, one might expect a lower speed limit for one astronaut, yet by all accounts the highest speeds were reached with only one on board, such as Gene Cernan claiming a lunar speed record of 18 kilometers/hour (1).

Did he execute any turns at that speed?

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So what is the allowable CoG envelope?

For what purpose?  The practical c.g. limits for vehicles are determined by intended use, as discussed later.

When a contractor says "acceptable" in his documentation, it means the envelope of operation inside which he guarantees the performance will meet the acceptance criteria imposed by the customer.  It does not mean the equipment may not be operated successfully outside that envelope, perhaps with degraded performance.  It means that if the equipment is operated outside the contractor-specified envelope, the contractor cannot be held liable for degradation, malfunction, damage, injury, or loss that ensues.

Conversely the practical envelope varies by use.  The real-world c.g. envelope for straight-and-level operation at high speed is different than the real-world c.g. envelope for operation on an incline or for low-speed, high-maneuverability operation on any terrain.  The speed envelope is different along uneven terrain than for flat ground.  The Grand Prix was intended to investigation the relationship between the practical limits and the as-specified limits.  Given that NASA has an acceptable design in-hand, the exercise was to determine confidence in the margins surrounding that accepted envelope.

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The allowable center of gravity location or the total LRV, including payload, is shown in figure 5-1. Loading the LRV such that the center of gravity falls outside the defined envelope will cause degradation of performance...

I can think of many things that degrade a vehicle's performance.  Does that mean that operating them under those conditions is impossible, such that by such inference we can conclude that claims to have operated them as such must be fraudulent?

You may have noticed I haven't posted for a few days.  I was down in Moab, Utah, enjoying a little thing called Jeep Safari where we take a bunch of 4x4s and drive them through all kinds of circumstances that happily exceed the manufacturer's specifications.  The Jeep reps were there, handing out color glossies.  Yes, from them can be computed the manufacturer's stated operational envelopes.  Did we see people happily exceeding them?  Yes, all the time.  Did we exceed them ourselves?  You betcha.  Did we roll over, skid, panic, die, or otherwise experience anything that would convince a non-believers that red-rock four-wheeling was a hoax?  Nope.  Did we all meet at the Blu Pig for KC BBQ and beers?  Yup.  Is Pasta Jay's named after me?  No, but I'm in there often enough that it might be.

In other words, I don't believe your handwaving.

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Now, my back of the envelope calculations put the CoG about 7 inches off center with one astronaut...

Show your calculations.  You are making an engineering argument without providing any engineering.  I'm not buying your handwaving one bit, and you won't show your work.  You've tried this same rhetorical stunt before.  You convince us that you really aren't interested in knowing.

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...let alone driven to the extreme.

Your one example of "driven to to the extreme" with only one occupant is a single claimed speed record.  However you have previously emphasized roll instability as the reason single-occupant operation would be problematic.  Do you understand that speed and maneuverability are not the same thing, and that "extreme" operation in one mode is not necessarily problematic in another mode?  Why are you blurring important distinctions?  Your handwaving didn't work at the other forum where you tried these identical claims and it work work here either.  When you are discussing engineering with engineers and calling them liars, you need more game than this.

Again we return to the Grand Prix example, which would be a test of roll stability with one occupant.  In that test the on-site crew even joked about the likely roll instability that would occur with an eccentric load in a sharp, high-speed turn.  The Grand Prix also tested lateral breakaway traction.  The operator discovered that he could steer quickly enough to correct loss of back-end traction before a tripping roll became likely.
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Offline Allan F

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Re: Were the Lunar Rovers faked?
« Reply #320 on: March 26, 2013, 01:07:01 PM »
I've used the drawing a few pages back as reference, and drawing on piece of paper, measuring and calculating, I've reached the conclusion, that the distance between the wheels and the astronauts positions in relation to each other and the LRV,  means that each astronaut puts 28.6% of his weight on the opposite side wheels. If they weight 30 kilos in lunar gravity, that's around 8.6 kilos. With 2 astronauts on board, the LRV is supposed to be perfectly balanced. With it's own weight, each side carries 25 kilos LRV and 30 kilos of astronauts. That's a total of 55 kilos on each side. Take one astronaut out, and the loads should be 46.4 kg and 33.6 kg. Total 80 kilos. That's a weight distribution of 42/58.

This is based on the LRV's mass of 300 kg in fully assembled state. I know there's lower weight quoted, but I think those numbers represent the weight of the frame/motors without batteries and instruments.

Edit: That's pretty far from 25/75 (or threequarters as somebody wrote).

Edit2: With a LRV weight of 210 kg, the distribution would be 33/67.
« Last Edit: March 26, 2013, 01:21:46 PM by Allan F »
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Offline Not Myself

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Re: Were the rovers ever designed for one astronaut?
« Reply #321 on: March 26, 2013, 01:26:28 PM »
Anywho, why do you need two Rover threads?

Because everyone knows the rover can't balance on just one thread.

Ah crap, beaten to the punch . . .
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Offline Echnaton

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Re: Were the rovers ever designed for one astronaut?
« Reply #322 on: March 26, 2013, 02:41:24 PM »
Anywho, why do you need two Rover threads?

Because everyone knows the rover can't balance on just one thread.

Ah crap, beaten to the punch . . .

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Offline Abaddon

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Offline Noldi400

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Re: Were the rovers ever designed for one astronaut?
« Reply #324 on: March 26, 2013, 03:56:58 PM »

In particular, one might expect a lower speed limit for one astronaut, yet by all accounts the highest speeds were reached with only one on board, such as Gene Cernan claiming a lunar speed record of 18 kilometers/hour (1).


I'm not sure where you got that idea. The "Cernan Speed Record" was claimed after coming down the steep slope from the "Scarp" with both astronauts firmly on board.


BTW, I'm still not clear on what your actual contention is.

Are you saying that:
   A) They shouldn't have done it that way.
   B) They wouldn't have done it that way.
   C) They couldn't have done it that way.

It seems to me that A & B are matters of opinion and professional judgment, and not really a subject for second guessing.

Only if it's "C" do you have anything to debate, in which case, please trot out the evidence.
« Last Edit: March 26, 2013, 04:06:10 PM by Noldi400 »
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Offline anywho

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Re: Were the rovers ever designed for one astronaut?
« Reply #325 on: March 27, 2013, 02:14:41 AM »


I'm not sure where you got that idea. The "Cernan Speed Record" was claimed after coming down the steep slope from the "Scarp" with both astronauts firmly on board.
 


My mistake

Offline anywho

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Re: Were the rovers ever designed for one astronaut?
« Reply #326 on: March 27, 2013, 02:17:52 AM »
To everyone who questions that the CoG with one astronaut moves outside of the acceptable envelope I would seriously question why you are being so difficult, I would suggest even someone innumerate would, upon understanding the astronaut weight is similar to the rover, put the CoG somewhere under the astronauts right buttock.

I used a simple formula for seesaws, I had my datum 3 feet from the center giving me a moment of 3*460 for the vehicle, and I did 2 possibilities for the astronaut, one at 1.5ft and one at 2ft from the datum (I believe these are both extreme for the CoG of the astronauts and the answer is somewhere in between). Then I divided the two moments by the combined weights giving me:

(1380 + 600)/860  for 1.5ft which is 2.3ft from the datum, or 8 inches off center
(1380 + 800)/860  for 2ft which is 2.5ft from the datum, or 6 inches off center

Like I say, I think that the true position of the astronauts is in between these two, and that is why I say 7 inches, I am being genuine and not trying to bend things in my favour.



I believe that you have not yet seen them.  There is a vast amount of material easily available on the lunar rover.  It takes the average person several weeks to read it all carefully.  It's not exciting reading, but then again most engineering documents are not meant to be entertaining.  And with the NTRS down until further notice, alternate sources must be sought out.

But consider this.  Given the characterization of what you have already read, which likely goes into meticulous detail, what is the most likely explanation for your inability yet to find documentation for single-occupant testing:  (a) the tests were never done, or (b) you just haven't run across them yet?


Lock in "a" Eddie.

If they were done I would have expected to have run across them by now, and I would expect any such findings to be in the operations handbook along with speed recommendations and CoG calculations etc.

The Grand Prix was intended to investigation the relationship between the practical limits and the as-specified limits.  Given that NASA has an acceptable design in-hand, the exercise was to determine confidence in the margins surrounding that accepted envelope.


Well the question I was asking was whether the LRV's were ever designed for one astronaut, so there should be no need to see if it could be done while on the moon, they should know before they get there, and should have appropriate guidelines.

Ostensibly, it is looking as though the rovers were never designed for one astronaut, and one astronaut takes the rover outside it's design parameters.

You are essentially saying the grand prix were testing limits, yet they went well outside the recommended CoG and well outside the speed limits, on the moon where any failure could be disastrous, and in vehicles with low tolerances.

The grand prix was certainly "rough mare"

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Maximum speed for design limit loads

Rough mare  8.5 km/hr

http://www.lpi.usra.edu/lunar/documents/NTRS/collection2/NASA_TM_X_66816.pdf


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Young puts the lunar rover through its paces by driving at speed and performing sharp turns and stops so that Duke can record it on film for the rover engineers using the data acquisition camera. This silent 16mm clip begins with the ALSEP site in the background. The rover speeds up to 10 kph and bounces dramatically in the craters, sending the wheels into the air. The wheels send up “rooster tail” sprays of dust and skid sharply in the turns. The clip concludes with Young driving off, bouncing in the craters towards the lunar module.

http://www.hq.nasa.gov/alsj/a16/video16.html

My emphasis.

Offline gillianren

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Re: Were the Lunar Rovers faked?
« Reply #327 on: March 27, 2013, 02:57:02 AM »
I used a simple formula for seesaws . . . .

Why?  What's the relevance?
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Offline Tedward

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Re: Were the rovers ever designed for one astronaut?
« Reply #328 on: March 27, 2013, 04:02:20 AM »

I used a simple formula for seesaws,

You start from the beginning. Like my old maths teacher used to say, show your workings out, this will get you more marks than a simple answer even if wrong but the method was correct. This way I can learn. I have seen what others here have put up and on purpose not worked through it (I like to do that when the mood takes me, understand what is going on). That is where you come in, if you are claiming it, you can show the sums that back it up and I can follow what you have painstakingly worked out and I might learn something. So far I see my gut feeling outdoing your gut feeling, so there has to be more or its a rum do.

How are the sums on the motors coming along?

Offline Captain Swoop

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Re: Were the Lunar Rovers faked?
« Reply #329 on: March 27, 2013, 05:17:47 AM »
I would like anywho to comment on the fact that we have film of the Rovers operating. We even have film of them operating with one man aboard. In fact, it is these films that he refers to in the thread.

How does he reconcile his belief that the Rovers don't work with the fact he is using film of them working to support his belief?