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The last three Apollo missions included a lunar roving vehicle. The picture below shows one driven with the front two wheels off the ground (a "wheelie").

A car that is "airborne" has all four wheels off the ground. Obviously, there is no air on the moon, but did the equivalent ever happen with the lunar rover? Did any Apollo lunar rover ever get all four wheels off the lunar surface?

John Young's wheelie

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    $\begingroup$ Hoons! ;-) $\endgroup$ – Fred Jun 26 at 1:02
  • $\begingroup$ @Fred In this case Loons! (lunar hoons) $\endgroup$ – uhoh Jun 26 at 1:53
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    $\begingroup$ I see nothing wrong with "airborne" with quotes like you have it, but if you wanted a literal term, I think "ballistic" would have done. $\endgroup$ – Mark Foskey Jun 26 at 15:00
  • $\begingroup$ @MarkFoskey, yeah except these days, "go ballistic" has other connotations. $\endgroup$ – Solomon Slow Jun 26 at 15:52
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    $\begingroup$ "Suborbital" :) $\endgroup$ – Russell Borogove Jun 26 at 18:40
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The videographer says yes!

This photo is described by NASA as:

The Lunar Roving Vehicle (LRV) gets a speed workout by astronaut John W. Young in the "Grand Prix" run during the first Apollo 16 extravehicular activity (EVA) at the Descartes landing site. This view is a frame from motion picture film exposed by a 16mm Maurer camera held by astronaut Charles M. Duke Jr. While astronauts Young, commander, and Duke, lunar module pilot, descended in the Lunar Module (LM) "Orion" to explore the Descartes highlands region of the moon.
Image Number: S72-36970
Date: April 21, 1972

That date and Dr Sheldon's comment led me to the voice transcript, where page 726 starts:

Duke: ... That maximum acceleration?
Young: No.
Duke: Man you are really bouting[sic] it.
CAPCOM: Is he on the ground at all?
...
Duke: He's got about 2 wheels on the ground. It's a big rooster tail out of all 4 wheels, and as he turns he skids the back end, breaks lose[sic] just like on snow. Come on back, John. ... Man I'll tell you Indy's never seen a driver like this. Hey when he hits the craters it starts bouncing it's when he gets his rooster tail. He makes sharp turns. Hey that was a good stop, those wheels just locked.
...
Duke: The suspension system on that thing is fantastic.
CAPCOM: That sounds good, we sound like we probably got enough of the Grand Prix, we're willing to let you go on from here. Call that a Grand Prix.
Duke: Okay. Man that was all 4 wheels off the ground, there. Okay, max stop.
Young: Okay, I don't want to do that.
Duke: Okay, excuse me.
Young: They say that's a no-no. ... Okay. I have a lot of confidence in the stability of this contraption.
Duke: Go ahead I'm going to run back in.
Young: I knew you'd rather get out and walk.
Duke: That's right.
CAPCOM: After he saw the way you drove.
Young: Well, when Charlie's in here it's a lot less bouncy.


Even though the math claims no, for a smooth approach to a ramp with a sharp crest, ignoring suspension effects (see comments below).

The top speed it ever reached was 18 km/h, or 5 m/s, under Gene Cernan's command.

Driving up a ramp, the angle to leave the ground is 2 arcsin (sg / v^2), where s is the distance that the vehicle is airborne, and where, on the moon, g = 1.625 m/s^2.

To get it barely airborne, set s to its wheelbase, 2.3 m. So the ramp would have to be steeper than
2 * arcsin (2.3 * 1.625 / 5^2) = 0.3 radians = 17 degrees.

"On the basis of crew observations and photographic coverage" it traversed slopes no steeper than 12 degrees.

"The maximum slope angle that could be negotiated by the LRV has been estimated to be of the order of 18 to 23 degrees."

So unless leadfoot Gene deliberately floored it over the sharp crest of a hill steeper than he could expect to maintain control, all four wheels could not have simultaneously left the surface.

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    $\begingroup$ Congratulations! You found it. +1 $\endgroup$ – DrSheldon Jun 26 at 4:25
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    $\begingroup$ The math is an ideal situation though. Imagine a rock which happens to push a wheel off the air briefly, or similar. It’s not a rigid structure which must all move as one (the wheels have suspension) $\endgroup$ – Tim Jun 26 at 9:24
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    $\begingroup$ Extending @Tim's comment, with sufficiently soft suspension, you can have liftoff without technically jumping an incline. Take a sharp turn,enough so the body leans outward. If the wheels then suddenly lose their traction, the (until now compressed) suspension will "boing" the outer wheels outward and can cause a brief time of no wheel contact, effectively using the quick release of the suspension spring as additional launch force. I've seen this happen on dune buggies and monster trucks and I don't know if the rover has any particularly different design that would exclude this. $\endgroup$ – Flater Jun 26 at 11:15
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    $\begingroup$ Regarding the math, there is also no need for front and back wheels to use the same ramp. A set of two smaller bumps interspersed at the same distance as the wheelbase, just barely higher than what suspension can cope with, would be enough. Additionally your formula assumes the landing to be at the same height as the jump-off. You can get much more air-(or vacuum)-time if you jump into a downhill section, as any skier can attest. $\endgroup$ – mlk Jun 26 at 12:52
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    $\begingroup$ More of it, stabilized, with corresponding air-to-ground audio, here: youtube.com/watch?v=X30z82aeSHw -- I still don't see what Duke sees. $\endgroup$ – Russell Borogove Jun 26 at 18:49

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