Were the Lunar Rovers faked?

[Echnaton]

Seriously? As an engineer who has done research into this area you dispute that claim?

This is quite unbelievable.

So if the rollover threshold for a car is 1g on earth it is not 1/6g on the moon?

If hitting a bump on one side causes the vehicle to rotate on it's axis will it not basically be gravity that stops that rotation? In space it will theoretically rotate forever, on earth 1g gravity will stop the rotation, and on the moon 1/6g will act against the rotation?.

On the moon if you hit a bump on one side will that side not rise up higher, and for longer, allowing for more rotation?

Lets be clear about this discussion. 

None of this has anything to do with the actual vehicle under discussion.  Your reasoning by analogy is unproductive and irrelevant when we have the design of the vehicle in question(the LRV), information on the environment in which it operated and actual video of its operation in that environment.  Your failure to analyze the actual vehicle negates the validity of your opinion as to how it operates.   Your assertions are unfounded and your arguments from those assertions are therefore meaningless. 

[anywho]

To amuse myself, I had a go at solving this particular problem of overturning the rover.


... it's easy to see that the necessary speed to overturn is proportional to the square root of the gravity, so that it takes roughly 2.5 times as much speed to flip the rover on the Earth as on the Moon.

I looked up how fast you have to be going to roll in a "tripped rollover", most cars and 4wds have a sideways rollover speed at between 5 and 6mph, which on the moon would mean a little over 2mph.

The rover has a wider wheel base but a higher COG so it will fit somewhere into the 5 to 6mph.

vehicle SSF Track
(ft)
Track/2
(ft)
Center of
Gravity (ft)
Sideways Rollover
Speed (mph)
Honda Passport 1.06 4.48 2.24 2.35 5.01
Jeep Grand
Cherokee 1.07 4.46 2.23 2.32 5.05
Jeep Cherokee 1.08 4.33 2.17 2.24 5.14
Chevrolet Suburban 1.08 4.96 2.48 2.53 4.88
Chevrolet Blazer
2WD
1.09 4.06 2.03 2.09 5.27
Chevrolet Blazer
4WD 1.09 4.08 2.04 2.14 5.26
Nissan Pathfinder 1.10 4.56 2.28 2.30 5.13
Chevrolet Astro van 1.12 4.93 2.46 2.42 5.06
Chevrolet S-10
pickup 1.14 4.04 2.02 1.99 5.42
Mazda MPV van 1.17 4.57 2.28 2.17 5.36
Honda CR-V SUV 1.19 4.53 2.27 2.11 5.43
Jeep Wrangler 1.20 4.33 2.17 2.01 5.51
Dodge Caravan van 1.23 4.79 2.40 2.15 5.47
Toyoto Tacoma
pickup 1.26 4.27 2.13 1.89 5.67
Saturn SL sedan 1.35 4.20 2.10 1.74 5.86
Toyoto Corolla
sedan
1.36 4.28 2.14 1.76 5.87
Nissan Sentra sedan 1.40 4.33 2.16 1.72 5.94
Honda Civic sedan 1.43 4.33 2.16 1.69 5.99
Dodge/Plymouth
Neon 1.44 4.33 2.16 1.68 6.01
Nissan Maxima
sedan 1.44 4.48 2.24 1.73 5.99
Toyota Camry sedan 1.46 4.54 2.27 1.73 6.02
Honda Accord sedan 1.47 4.57 2.28 1.72 6.04
Chevrolet Camaro 1.50 4.55 2.28 1.68 6.09

Stupid computer, the last figure is the sideways rollover speed (mph)

http://www.accidentreconstruction.com/research/suv/rollovers%5B1%5D.pdf

So they went 8 to 10mph over a sometimes very uneven surface with a very low coefficient of traction. If they end up sideways which will be very easy given the low traction and the uneven surface, and if they hit a trip hazard like an embedded rock, crater wall, or mound, then they will possibly roll at as little as 2 1/2mph.

And that is with the rover nicely balanced with two astronauts on board.

No roll cage is deemed necessary, no upper body harnesses, no worries.

It might be time to wake up and smell the coffee.

[Laurel]

Anywho, you claim the rover could not be "sat on" in Earth gravity.

So where did they film it being driven by astronauts, if not on the Moon?

Your hand waving arguments are not even consistent.

It might be time to answer this question.

[nomuse]

I looked up how fast you have to be going to roll in a "tripped rollover", most cars and 4wds have a sideways rollover speed at between 5 and 6mph, which on the moon would mean a little over 2mph.

Which is why cars are rolling over all across the streets and highways.

Heck, I rarely drive at under 6 MPH, even in a parking lot.  I have driven a bit less than 20 times that -- and on just a two-lane blacktop.

Could it be that most people -- and that includes astronauts -- figured out somewhere around their first bicycle that it was a bad idea to turn the wheel hard over at speed?

[nomuse]

Now, I know you were hoping to lose the connections in the forest of uneeded detail, but your scenario requires the LRV -- a vehicle with a top speed of 15 MPH, typically driven at half that -- to be traveling SIDEWAYS at 2.5 MPH or more.  On a regular basis!  Perhaps you will show me the clip some time of the Apollo 16 astronauts pulling a bootlegger reverse in order to escape from pursuing Selenites...

[Not Myself]

Which is why cars are rolling over all across the streets and highways.

Yes, but when they have those concrete barriers on the side of the road, then they just bounce right back and continue on.

[Not Myself]

Perhaps you will show me the clip some time of the Apollo 16 astronauts pulling a bootlegger reverse in order to escape from pursuing Selenites...

I wouldn't be surprised if I could find some low-budget film with just that

[Tanalia]

Note that the calculation of the LRV's SSF that Jay provided is a good margin higher than any of the Earth vehicles.

[nomuse]

I was gonna say, "Thrilling LRV chase scene" is not a phrase you will ever encounter.  But then I remembered "Space Mutiny."

Slab Bulkmeat -- only hero who could roll a floor buffer...

[Jason Thompson]

So they went 8 to 10mph over a sometimes very uneven surface with a very low coefficient of traction.

10 mph was the maximum speed. They rarely got that high.

If they end up sideways

And how will they end up sideways?

Here's a suggestion: work out how many scenarios cause cars here on Earth to end up traveling sideways, then work out how many of those could possibly transpire on the Moon.

which will be very easy given the low traction

Since it is the traction between the wheels and the road that causes a car on Earth to turn enough to travel sideways from a forward direction of travel, your statement is contradictory. The low traction would make it less likely that any sudden turn of the steering would translate to a 90 degree turn in the rover's attitude.

No roll cage is deemed necessary, no upper body harnesses, no worries.

It might be time to wake up and smell the coffee.

It might be time for you to stop pretending to be an engineer by pulling some numbers from Google.

It might also be time to answer the other questions that have been put to you, such as what research you have done and what exactly you propose was done if not what the Apollo record appears to show.

[Tedward]

So they went 8 to 10mph over a sometimes very uneven surface with a very low coefficient of traction. If they end up sideways which will be very easy given the low traction and the uneven surface, and if they hit a trip hazard like an embedded rock, crater wall, or mound, then they will possibly roll at as little as 2 1/2mph.

And that is with the rover nicely balanced with two astronauts on board.

No roll cage is deemed necessary, no upper body harnesses, no worries.

It might be time to wake up and smell the coffee.

Whilst the moose test is not quite a trip over test, I would think it shows that there is more to this than meets the eye. Interesting to see what they can do.

How is the proof that the motors could not cope coming on? Been 17 pages and might have missed it.

[anywho]

Which is why cars are rolling over all across the streets and highways.

Heck, I rarely drive at under 6 MPH, even in a parking lot.  I have driven a bit less than 20 times that -- and on just a two-lane blacktop.

Your parking lot is not a very uneven surface with extremely low traction, nor are the streets and highways.

Now, I know you were hoping to lose the connections in the forest of uneeded detail, but your scenario requires the LRV -- a vehicle with a top speed of 15 MPH, typically driven at half that -- to be traveling SIDEWAYS at 2.5 MPH or more.  On a regular basis! 

Why on a regular basis? It only has to happen once to roll the vehicle therefore it only has to be a possibility before a rollcage and harness are needed.

And, on an uneven surface with an extremely low coefficient of traction it is not exactly an unforeseeable possibility, more likely a highly probable event.

Note that the calculation of the LRV's SSF that Jay provided is a good margin higher than any of the Earth vehicles.

Not with two astronauts sitting up high and weighing 800lbs, especially when the vehicle only weighs 460lbs.

And how will they end up sideways?

Here's a suggestion: work out how many scenarios cause cars here on Earth to end up traveling sideways, then work out how many of those could possibly transpire on the Moon.

One scenario is gong off road onto uneven terrain in slippery conditions, then it is very easy to end up sideways. If you are ever in that scenario you would be well advised to crawl along, even here on earth.

Can we all agree that scenario is very likely to happen on the moon? Or do you guys just want to relate your experiences in parking lots to the moon.

[Jason Thompson]

One scenario is gong off road onto uneven terrain in slippery conditions,

How slippery is the lunar surface?

The surface of the Moon is uneven and covered in regolith, but the regolith is quite cohesive. The rover wheels also can dig into it quite a bit. How does that affect the momentum of the rover as it moves sideways?

Can we all agree that scenario is very likely to happen on the moon?

No, we can't. It is your burden to prove that.

[Jason Thompson]

It only has to happen once to roll the vehicle therefore it only has to be a possibility before a rollcage and harness are needed.

Wrong. It has to exceed a certain level of probability, with an appropriate level of severity of consequence, before the extra engineering complexity and weight are considered necessary over, say, training the astronauts for months on how to drive the rover without slipping sideways on uneven, loose terrain. Guess which they favoured.

There is a chance while driving along a motorway I might get my small two-seater car hit head on by an oncoming articulated truck, both of us going at 70 mph. Or I might get hit by a train driving over a crossing (as has just recently been in the news here in the UK). By your logic, since that only has to happen once before safetey measures are 'needed',  my little car should be engineered to survive that. It won't. In both cases it will be wrecked and I will be very probably not only dead but in several pieces.

Why isn't my car engineered to survive those impacts and protect me? Because the designers reckoned that the probability was low enough that it didn't need to be designed for in favour of teaching people how to drive safely and reduce the risk of such events occurring.

But we'll just add risk assessment to the list of things you know nothing about.

And, on an uneven surface with an extremely low coefficient of traction

Numbers for this?

it is not exactly an unforeseeable possibility, more likely a highly probable event.

Probability is another thing that works with numbers. Where are yours?

[Tedward]

Can we all agree that scenario is very likely to happen on the moon? Or do you guys just want to relate your experiences in parking lots to the moon.

Bold mine.

Eh?

For my part I compare what I know about earth bound cars with your claims on earth bound cars to show you do not have all the info and perhaps getting it wrong. This is the info you are using to compare to the rover.