Were the Lunar Rovers faked?

[gwiz]

They need traction to accelerate, brake, and steer. Taking a 2wd onto a loose surface on earth is a dodgy prospect no matter how easy you take it.

I used to go rallying many years ago.  I have personal experience of two-wheel drive on loose surfaces.  We used to go well over six times faster than the rovers.

[nomuse]

So lemme get this straight; an unsourced, undocumented quote from "somebody" at NASA giving a poetic description of hypothesized performance of a Rover on Earth is used -- in lieu of any technical documentation -- to contrast the desired performance of the real thing on the Moon?

I think next time I hang a show I'll use the first adjective I find in Century's advertising instead of bothering to look up the actual capacity of the dimmers in watts.  After all, "high power" is all the real information I need to design my plot, right?

The onus isn't to show that physics is wrong and that the Rover could operate properly whilst still adhering to all possible hyperbole from non-technical sources.  The onus would be to show the actual construction of the Rover is incapable of bearing the projected loads.

Question #2 gets closer to being meaningful, but also stops well short.  Many, many things have a higher required acceleration or a lower coefficient of friction.  Yet, drag racers and toy cars and snow tires still work.  Why assume that the Rover looks exactly like a car in all respects, except that it is operating at 1/6 g?  Do you think the LM looks exactly like a quonset hut, only is operating in vacuum?  Or do you assume, in gross ignorance of both physics and design, that it is impossible to design a vehicle to provide better traction?  Are you really that ignorant to the variety of contact area and tire design that exist already down here on Earth?

This is nonsense.  Practically techno-babble.  And not a hint of a number anywhere in it (not that numbers can't be bafflegab too, but numbers are a heck of a lot harder to weasel away from when you get them wrong.)

[nomuse]

Incidentally, all this 4wd v. 2wd stuff is just distraction.  The Rover had individual wheel motors in an arrangement not found on any car on the highway down here.  My guess is the OP wanted to make a statement about the Rover "only being" 2wd when he first came up with his claim, but either realized after doing the most basic research it wasn't sustainable, or floated it in yet some other forum and got shot down.

[Count Zero]

Power:

The rovers would appear to be massively underpowered, they have 4 x 1/4hp motors giving a grand total of 1hp to drive a 1,500lb vehicle. One horsepower is low powered even for a mobility scooter, imagine putting seven big blokes on a low powered mobility scooter and seeing what performance you get out of it, yet on the moon they hooned around no problems at all.

1 Horsepower vehicle moving at speed in 1 Earth gravity.  Total weight > 1,800lbs

[Glom]

Let me weigh in on one point. Mass is the same, but with a lower gravitational acceleration, the speed when they hit the seat will be less. This means less momentum.

So yes, gravitational field does make a difference to the impact force on the seat, not because m is different, but because v is different.

[Tedward]

They need traction to accelerate, brake, and steer. Taking a 2wd onto a loose surface on earth is a dodgy prospect no matter how easy you take it.

I used to go rallying many years ago.  I have personal experience of two-wheel drive on loose surfaces.  We used to go well over six times faster than the rovers.

Love rallying. Spectator though. Took an interest before the Quatro came along. Watch some of them cars on loose surfaces and insane speeds. Never did get to the 1000 lakes. Yeah, two wheel drive useless. And rear two wheel at that when I were a nipper.

Got a ride a rally school once, 70 or so on loose gravel road and being on a training stage in Mid Wales, not straight.

[Tedward]

To take a 4WD onto a loose ungroomed surface here on Earth would not be counter-intuitive to most people, however, most people would balk at the idea of taking a 2wd vehicle onto a loose ungroomed terrain here on earth because, quite sensibly, it is unlikely a 2wd, with half the traction of a 4WD, would have enough traction. Well, on the Moon a 4WD does not have anywhere near half the traction of a 4WD on earth, it has only a piddly 1/6 the traction and that is true for steering, braking, and accelerating.

I would imagine that training plays a bigger part than the car. The amount of people in the UK that seemed to have been caught out in the recent years dusting of white stuff in the UK. Tyres also play a part I think in the cold and snow. Wonder what impact they had on the rover? Do you know?

I would think that many people that drive a 4be4 would be a bit wonky on the grass verge outside a school let alone a track. Why this argument?

[ChrLz]

Notwithstanding your utter refusal to supply any figures whatsoever, nor anything anywhere near an engineering analysis, there does seem to be another elephan tiny flaw in your fantasy, anywho.. (it is certainly not a theory, let alone a hypothesis).

There is an awful lot of footage showing the LRV in operation.  All that footage shows, without exception, all the telltales of 1/6 gravity.  All that footage shows, without exception, all the telltales of operation in a vacuum.  All that footage shows operation in a vast sunlit environment without the scattered light from an atmosphere.  That footage shows the way it was deployed, the speed at which they traveled, their entry and exit, the beautiful parabolas of dust - impossible on earth.  Do I need to go on?  And much of it is in very high definition...

Now, bearing in mind that you, 'anywho', have already comprehensively shown your ignorance of what would be needed to actually debate this issue in any serious way, there seem to be a few obvious options:
1. The LRV was well, and adequately, designed to do the job it had to, and you are totally out of your depth and completely wrong (or trolling).
or
2. That footage was faked by using an LRV on Earth instead.  Now that obviously has serious problems for your claim, because if it worked that flawlessly in 6x the gravity and an atmosphere, then your entire argument is even more discredited.
or
3. That footage was faked entirely, ie by some type of special effects.  Given that no CG techniques existed at the time, it would have to be by models, hand drawing, animation or similar (feel free to speculate..).

I'm going with option 1.  Option 2 is equally damning for you, anywho, and as for option 3..  can you show us *any* special effects footage that come anywhere near the perfection of the movie footage of the LRV (which I take it you have actually seen..)?  Even today, with the computer graphics processing power that is now available, such fakery would be close to impossible to pull off - as even the very best graphics wizards on our planet (the ones who did Avatar, Lord of the Rings, etc) will tell you.


This claim is possibly as silly as the one about the stars visibility...

ADDED:
Here's just a short example of some of that footage, anywho:

Examine it closely - note the MANY telltales of 1/6 g and vacuum, also note in the second half how much terrain is being covered and all the tiny details like the (single) shadows..  It is beautiful footage (and there are even better transcriptions of it around..)

[Zakalwe]

Traction:

To take a 4WD onto a loose ungroomed surface here on Earth would not be counter-intuitive to most people, however, most people would balk at the idea of taking a 2wd vehicle onto a loose ungroomed terrain here on earth because, quite sensibly, it is unlikely a 2wd, with half the traction of a 4WD, would have enough traction. Well, on the Moon a 4WD does not have anywhere near half the traction of a 4WD on earth, it has only a piddly 1/6 the traction and that is true for steering, braking, and accelerating.

Fully loaded the rovers on the moon have a mass of approx 1,500lbs, yet they only have approx 250lbs of weight on the ground to try and accelerate, steer, and brake the 1500lb mass, and they are on a loose surface. The suggestion anyone can go 4WD driving on a loose surface in 1/6g is ludicrous.

I know defenders of the apollo missions will say that the lunar dust binds together so it is not loose, and will quote astronauts as saying they had big trouble controlling the rovers. The problem with both these excuses is that it is not what we see in the video and photographic footage, instead we see a surface that is very loose with dust being disturbed very easy by the astronauts moving around in it, and we see no control problems with the rovers either in driving or the photos of the tracks. It would appear as though they are merely paying homage to the physics while, at the same time, not bothering to fake any traction difficulties for TV.

Here's a one-wheel drive vehicle seemingly doing OK in loose sand and dust.
Is that fake too?

[anywho]

So lemme get this straight; an unsourced, undocumented quote from "somebody" at NASA giving a poetic description of hypothesized performance of a Rover on Earth is used -- in lieu of any technical documentation -- to contrast the desired performance of the real thing on the Moon?

I think next time I hang a show I'll use the first adjective I find in Century's advertising instead of bothering to look up the actual capacity of the dimmers in watts.  After all, "high power" is all the real information I need to design my plot, right?

The onus isn't to show that physics is wrong and that the Rover could operate properly whilst still adhering to all possible hyperbole from non-technical sources.  The onus would be to show the actual construction of the Rover is incapable of bearing the projected loads.

This is actually the best defense against the argument that the rovers could not be so weak that they could not be sat on here on earth, yet could be jumped onto on the moon, namely that all the talk about the astronauts not being able to sit on them here on earth is something of an urban myth.

Perhaps we can find common ground by all agreeing that if the rovers cannot withstand the static weight of the astronauts here on earth, then they cannot be jumped onto on the moon.

And, if the chassis are not strong enough to hit bumps at 10kph here on earth, then they are not strong enough to hit bumps at 10kph on the moon.

Let me weigh in on one point. Mass is the same, but with a lower gravitational acceleration, the speed when they hit the seat will be less. This means less momentum.

So yes, gravitational field does make a difference to the impact force on the seat, not because m is different, but because v is different.

Absolutely, but we are often told the astronauts cannot even sit on the rovers here on earth, but they can jump rather clumsily onto them on the moon. They wouldn't possible be able to jump onto them on earth fully suited so when people say the rovers can't withstand being sat on here on earth they cannot be referring to the astronauts, fully suited, trying to jump onto them.

[anywho]

Power:

The rovers would appear to be massively underpowered, they have 4 x 1/4hp motors giving a grand total of 1hp to drive a 1,500lb vehicle. One horsepower is low powered even for a mobility scooter, imagine putting seven big blokes on a low powered mobility scooter and seeing what performance you get out of it, yet on the moon they hooned around no problems at all.

1 Horsepower vehicle moving at speed in 1 Earth gravity.  Total weight > 1,800lbs

Well, that motor could be more than 1hp in the context we are talking about, mobility scooters can be 1hp (they can be up to 3hp) so they might be a more accurate comparison.



I think they used the power to weight ratio to decide 1hp would be adequate, but power to weight is a bit of a misnomer and it really should be power to mass.

1hp to drive 250lbs would seem to be almost standard, but 1hp to accelerate 1500lbs is ridiculously low.

[gillianren]

Perhaps we can find common ground by all agreeing that if the rovers cannot withstand the static weight of the astronauts here on earth, then they cannot be jumped onto on the moon.

No, we can't.  Not until you provide some numbers.

[anywho]

And naturally you have at your disposal all the reams of data on the construction of the rover and the research and development that went into it, so can easily provide us with the source that shows conclusively that the rover as constructed could not operate under these conditions.

No? Oh well...

I'll just pop upstairs and read the rather interesting book about how the rovers were designed and built.

I have spend quite a bit of time looking to see how they tested the rovers for 1/6g, and all I can find is a comment that the wheels were tested on some machine but I cannot find any more about what that was, and also that they used a scale model for testing.

A scale model reduces the mass as well as the weight so it will only test if a lightweight rover will work on earth, not 1/6g. The best testing would probably be something like a skidcar where the weight is reduced but the mass is the same, but it would be hard to make an off road version.



If you find anything in your book about how they tested for 1/6g I will be interested if you want to post it.

[anywho]

Perhaps we can find common ground by all agreeing that if the rovers cannot withstand the static weight of the astronauts here on earth, then they cannot be jumped onto on the moon.

No, we can't.  Not until you provide some numbers.

Do I really need numbers to say that if the astronauts, in jumping onto the rover, clear the rover by 6 inches on the moon then the forces on the rover will be the same as a fall onto the rover of 1inch here on earth?

Do I need numbers to say that a fall from 1inch puts more stress on the frame than the static weight weight of an astronaut?

It's basic physics and common sense (although, admittedly, for most people, myself included, it does take a bit of time to stop thinking of weight and instead think in terms of mass)

[nomuse]

This is actually the best defense against the argument that the rovers could not be so weak that they could not be sat on here on earth, yet could be jumped onto on the moon, namely that all the talk about the astronauts not being able to sit on them here on earth is something of an urban myth.

Perhaps we can find common ground by all agreeing that if the rovers cannot withstand the static weight of the astronauts here on earth, then they cannot be jumped onto on the moon.

No, I'm not taking that one either.  The Moon is not the Earth.  Not only that, you are still creating non-measured conditions.  What is "withstand?"  What is "jumped onto?"  If you want to talk about the engineering of the Rover, talk about it in the context of the job it was designed to do -- not about some job that in your mind is similar.


Sorry for excerpting, but when I get three deep of quotes unquotes of quotes I start feeling like I'm in a Groucho Marx sketch ("Jamison, take a letter!")