Were the Lunar Rovers faked?

[anywho]

Hi, I posted an argument on a science forum that the apollo rovers are nonsensical for driving on the moon, it is derived from another posting of mine on a different science forum that has already been posted on this site (I was just going to bump that thread but because the original link does not work, and a message came up asking me to consider making a new thread, I have started this thread)

Here is what I wrote:

There are so any problems associated with the Lunar Rover that it would seem almost farcical to believe they could possibly be real.

The construction:

It is often said that if astronauts could not even sit on a Lunar Rover here on Earth because the Rovers were built of such lightweight construction that they "would have collapsed in 1 g if the crew sat on it." (1), and that the " The vehicle could support its own weight on earth, but no more" (2).

It would seem to defy basic physics to build a weak design because the astronauts on the moon are not just gently putting their weight onto the vehicles, they are also imparting their considerable momentum onto the vehicles and that momentum will be the same on earth as it is on the moon, the mass of the astronauts and their suits do not change. If we take as an example the method the astronauts supposedly used for getting onto the Rovers we can see that they jump up and onto the vehicles:

Getting to sit on the Rover seat in a stiff pressure suit from the lurain was not so easy. The astronauts found they had to stand facing forward, then with an upward and sideways kick, jump up with their legs and arms stretched out ahead to hopefully land in the middle of their seat.

http://www.honeysucklecreek.net/msfn_missions/Apollo_15_mission/hl_Apollo15.html

p=mv tells us that the momentum that the astronauts have, and therefore the forces they will impart, are the same on the Earth as they are on the Moon as long as they are traveling at the same speed. This means that if the astronauts, in the final stage of jumping onto the rover, fall from a height of 6 inches on the moon then the forces they impart onto the rover will be the same as if they fell from a height of 1 inch here on earth.

Once we understand that the forces of momentum are independent of weight then it is nonsensical to suggest you cannot even sit on a rover on earth, but you can jump on one on the moon. The astronauts and their suits have the same mass on earth as they do on the moon and it is very hard to imagine that jumping onto the rovers on the moon they would have less velocity than sitting on them here on earth.

Similarly, driving the rovers on an uneven terrain where the chassis is often forced to change directions vertically, the forces will be very similar, if not the same as here on Earth. Hitting a mound at 10kph will impart the same forces on the vehicle as hitting a mound at 10kph here on earth, the mass and velocity are the same. If you can't hoon around a crater filled terrain here on earth with the vehicles then you can't do it on the moon. If you can't sit on a rover on earth then you can't jump onto one on the moon.

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.

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.

Uphill there would be some benefits from being on the moon but driving on a flat surface on the moon you would get the same performance as on earth, simply because it is the same mass that has to be accelerated.

Balance:

The rovers are horribly unbalance vehicles, they weigh approximately 460lbs and the astronauts weigh approx 400lbs each fully suited (3), this means when one astronaut is driving there is approximately 3/4 of the weight on one side of the vehicle:



I doubt many of us would want to drive such an unbalanced vehicle over an uneven terrain here on earth, but on the moon where 1/6 g means it is much more likely to roll the suggestion becomes untenable. If the driver were to hit a rise on the unweighted side of the vehicle then the rover will rise 2, 3, or 4 times higher than it will hitting the same bump on earth (depending on the degree of the slope).

In conclusion:

We are supposed to believe they took a 4WD to the moon that was of such a lightweight design that they couldn't sit on it on earth, but they could jump on it on the moon?

They had no traction problems on a loose surface in 1/6g even though 1/6g equals a whooping 1/6th of the traction?

They had ample power driving a 1500lb mass with a 1hp vehicle?

They could hoon around with one astronaut on one side of the vehicle (approx 3/4 the weight on one side), on an uneven terrain hitting bumps in 1/6g, with no worries at all about rolling?

(1) http://ares.jsc.nasa.gov/HumanExplore/Exploration/EXLibrary/docs/ApolloCat/Part1/LRV.htm

(2) http://www.hq.nasa.gov/office/pao/History/SP-4204/ch23-3.html

(3) http://www.hq.nasa.gov/alsj/a17/A17_LunarRover2.pdf

[anywho]

Sorry, I forgot the link to the original posting:

http://www.thenakedscientists.com/forum/index.php?topic=47147.0

[gwiz]

Why do you think the rovers need a lot of traction?  Are they doing high-g turns, massive acceleration, heavy braking?  Do they even have to keep to a particular course?

[onebigmonkey]

The discussions of the LRV's inability to withstand an astronaut's mass on Earth clearly refer to the flight versions.

As you point out several times, it was 1/6g, and the flight version was designed to cope with loadings in that environment. Feel free to provide actual calculations proving the design was inadequate for the environment in which it was designed to operate.

1/6g also applies to the resistance to movement of the rover - there is less gravitational force holding it in place, so less energy is required to get it moving.

As for rolling, why would a low centre of gravity vehicle be in any more danger of rolling on the moon than on Earth? All the forces involved in making that likely are relatively the same Is everyone who has every driven a jeep or a go kart terrified it will tip at the drop of a hat?

I'll let the physics and engineering guys go for the rest!

[anywho]

Why do you think the rovers need a lot of traction?  Are they doing high-g turns, massive acceleration, heavy braking?  Do they even have to keep to a particular course?

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.

They are relatively high performance compared to say an unmanned rover, and you certainly wouldn't want to end up going sideways on such an uneven surface, with such unbalanced vehicles, on the moon where rolling would be many times easier.

[RAF]

We are supposed to believe...

3 things....one...welcome to the board.

Two...who is this "we" you speak of?...I certainly do not think your ideas have a lick of merit, so please do not "include" anyone but yourself in your "we are supposed to believe..."

...and three...I really do not care what you believe, only what you can prove with evidence. So far, all you have done us make unsubstantuated ignorant claims regarding what YOU think.


Awaiting the evidence that the LRV's were faked...good luck...

[anywho]

The discussions of the LRV's inability to withstand an astronaut's mass on Earth clearly refer to the flight versions.

As you point out several times, it was 1/6g, and the flight version was designed to cope with loadings in that environment. Feel free to provide actual calculations proving the design was inadequate for the environment in which it was designed to operate.

1/6g also applies to the resistance to movement of the rover - there is less gravitational force holding it in place, so less energy is required to get it moving.

As for rolling, why would a low centre of gravity vehicle be in any more danger of rolling on the moon than on Earth? All the forces involved in making that likely are relatively the same Is everyone who has every driven a jeep or a go kart terrified it will tip at the drop of a hat?

I'll let the physics and engineering guys go for the rest!

It wasn't just the static weight of the suited astronauts that the rovers had to be designed to withstand, it was also the momentum of the mass as they jumped up and onto them, and that mass doesn't change from the earth to the moon.

The rovers are significantly higher than a "go cart", and when only one astronaut is on board they are not sitting in the middle like they would on a go cart. A jeep might weigh 4,000lbs with a 200lb driver so one wouldn't expect to feel too unbalanced in that situation.

It is undeniable that rolling would be many times easier on the moon than earth, if you hit a bump you will rise higher for longer, you essentially have the same mass thrashing about with only 1/6 the weight to keep it anchored.

[gillianren]

So let's see your numbers, then.  You can't prove anything without them.  You can just speculate, and anyone can speculate without merit.

[RAF]

It is undeniable that rolling would be many times easier on the moon than earth, if you hit a bump you will rise higher for longer, you essentially have the same mass thrashing about with only 1/6 the weight to keep it anchored.

I'm not at all surprised that the Astronauts didn't "race" the rover...so they drove "conservatively"...so what?

Please present your evidence (not speculation) that the rovers were in fact faked, or retract that claim.

Thankyou.

[anywho]

So let's see your numbers, then.  You can't prove anything without them.  You can just speculate, and anyone can speculate without merit.

I wouldn't think any numbers are necessary to prove that the mass of the astronauts is the same on the moon as it is on earth, and because the astronauts on the moon have to jump onto the rovers it is therefore apparent that the rovers had to be designed to withstand that mass at a certain velocity, yet it is claimed that they could not withstand being sat on here on earth.

And that is just the astronauts getting onto the rovers, when they drive them over an uneven surface hitting bumps etc the forces on the chassis as it is forced to change direction will be largely the same as here on earth simply because the mass and velocity are the same.

I will check in again tomorrow.

[gillianren]

I wouldn't think any numbers are necessary to prove that the mass of the astronauts is the same on the moon as it is on earth, and because the astronauts on the moon have to jump onto the rovers it is therefore apparent that the rovers had to be designed to withstand that mass at a certain velocity, yet it is claimed that they could not withstand being sat on here on earth.

No, but it is your responsibility to provide the numbers that show it's relevant.  Weight and mass being different things, there are different requirements for them. 

And that is just the astronauts getting onto the rovers, when they drive them over an uneven surface hitting bumps etc the forces on the chassis as it is forced to change direction will be largely the same as here on earth simply because the mass and velocity are the same.

I assume you mean "the same as they would be on Earth."  As opposed to "the same as each other."  Which would make no sense.  But either way, the only way to demonstrate that your premise as to why it shouldn't work is correct is to do the math.  Common sense lies.  The Moon is not the Earth, and things that are intuitive to us on Earth aren't always reliable on the Moon because of the different gravity, etc.  You think the mass is important, but you haven't shown that it is important.  You haven't demonstrated that the mass of the astronauts as they jump into the rovers would create the same stresses as their sitting in the rover in Earth gravity, and without demonstrating that, you have shown precisely nothing except that you, at least, understand that mass and weight aren't the same thing.

[Valis]

As you are unwilling to provide the numbers or, say, a force diagram to show that the LRV was "massively unbalanced" (quote from your other thread) with one astronaut on it, perhaps you could proceed by explaining us how all the LRV footage from the Moon was faked. Please pay special attention to the behaviour of regolith when it's ejected from the wheels.

[RAF]

I will check in again tomorrow.

Please change your "argument" before then...your current one isn't "working".

[Jason Thompson]

I wouldn't think any numbers are necessary to prove that the mass of the astronauts is the same on the moon as it is on earth,

No, but they are necessary to prove that the rover could not do what is claimed. You have not actually worked from any technical description of the rover, just some hyperbole about its lack of weight-bearing ability on Earth. This is odd (and common among HBs) since all the information you need to assess the capabilities of the rover quantitatively is freely available from a variety of sources. Have you checked any of them?

and because the astronauts on the moon have to jump onto the rovers it is therefore apparent that the rovers had to be designed to withstand that mass at a certain velocity, yet it is claimed that they could not withstand being sat on here on earth.

Why do you think that how an astronaut in training would get on a rover differently on Earth than the Moon? He's just as encumbered in his mobility by the suit in training.

And that is just the astronauts getting onto the rovers, when they drive them over an uneven surface hitting bumps etc the forces on the chassis as it is forced to change direction will be largely the same as here on earth simply because the mass and velocity are the same.

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.

[RAF]

...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.

This really is the bottom line, anywho...you see, it is established historical fact that the rovers worked "as advertised". Since you think differently, the onus is on you, and you alone to provide evidence that the rovers could not operate in the Lunar enviorment.

Simply saying, "I don't understand how it could have been done" is only evidence that you come to this subject from ignorance.