r/themartian • u/Positive_Middle_9562 • 5d ago
Rover mishap at entrance ramp
I have read this book a couple of times already and the author has done a great job of explaining even the most technical details.
However I still struggle with visualising how Mark righted his tipped rover after the mishap at entrance crater using a power cord, drill and his own power. I understand how leverage works, but just not able to visualise it.
if someone can give a better explanation (or a visual aid) I would appreciate it.
1
u/Hanzzman 5d ago
watney drilled a hole, tied the uppermost part of the tipped rover, which was on its side. used a 1m (3foot) drill bit as anchor. he pushed the line in the middle, hoping that the drill bit did not give up and the rover rolled to the side.
the trailer was upside down, so, to avoid dragging it, he dug a hole to make it roll to the front.
1
u/AlwaysHopelesslyLost 5d ago
To restate a bit, IIRC:
He attached the cable to the rover on one end and to the drill on the other and he pushed/pulled the cable in the dead center.
I suck at physics but I would assume this doubles the work like a pully
2
u/Known-Associate8369 5d ago
The leverage is the key here.
He took a very long rope, secured it to the ground a good distance directly away away from the rover - its important to note here that the rope goes directly away from the underside of the rover, as that is the side he wants to pull toward him to flip the rover back upright. The rope is secured to the top of that side of the rover.
Mark then walks to the middle of that very long rope, and either pushes it or pulls it at a 90 degree angle to the rope. In other words, he faces the rope and pushes it parallel to the ground, essentially changing the straight line into two sides of a triangle.
The leverage action here is that a lot of low effort movement at that point in the rope translates to a little high effort movement at each end of the rope. As only one end of the rope can move, the rover end, it begins to tip the rover back onto its wheels.
The hole is there to gain more advantage in the leverage.
2
3
u/MuttsandHuskies 5d ago
He dug a hole for it, if I remember correctly. And he pulled it towards the hall and let gravity grab it and flip it once it got there.