Water Found Deep Inside the Moon

Re:Water Found Deep Inside the Moon by tveita on Friday August 25, 2017 @09:03AM (#15098093)

You could run the mass driver in reverse for landing, but you'd have to aim well.

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Re:Water Found Deep Inside the Moon by ChuckMcM on Friday August 25, 2017 @02:37PM (#15101022)

That would be rather difficult :-) I wonder sometimes however if you've ever dropped a magnet down a conductive pipe you see how the eddy currents prevent it from falling through. If you had series of conductive rings that were of a large diameter and you had electromagnets on the outside of your cargo container could you make a landing pad that primarily used the eddy currents to slow you to landing velocity? That would be a fun problem to give the physics class.

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Re:Water Found Deep Inside the Moon by adrianN on Friday August 25, 2017 @10:10AM (#15098537)

That would be an amazing feat with the risk of destroying an extremely expensive piece of equipment.

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Re:Water Found Deep Inside the Moon by stcredzero on Friday August 25, 2017 @02:06PM (#15100746)

Is it any more amazing than doing an orbital rendezvous?

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Re:Water Found Deep Inside the Moon by adrianN on Friday August 25, 2017 @02:29PM (#15100948)

You brake before getting close to whatever you want to rendevous with. You couldn't brake if you wanted to hit the nozzle of your mass driver to use it for braking.

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Re:Water Found Deep Inside the Moon by stcredzero on Friday August 25, 2017 @03:26PM (#15101451)

You brake before getting close to whatever you want to rendevous with.

This makes me question whether you actually understand how orbital rendezvous works. How about as an exercise, you explain why I would say this. Otherwise, I think the resulting conversation would be tiresome and not worth my time.

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Re:Water Found Deep Inside the Moon by SAI_Peregrinus on Saturday August 26, 2017 @10:12AM (#15105525)

The relative speed of two objects docking in orbit is very small. You brake or accelerate as you get close to matching orbits.

The relative speed of a capsule and the mass driver will be very high IF you're using the mass driver to slow down substantially. That's in the definition, you're using it to slow down so the initial relative speed at contact must be high. The higher the speed the less energy you have to waste lowering your orbit (slowing down beforehand). If you're slowing down beforehand enough that your relative speed of contact is low then you don't need the mass driver to brake.

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Re:Water Found Deep Inside the Moon by adrianN on Friday August 25, 2017 @04:20PM (#15101851)

How about you, just as an exercise, compare the difference in velocities of the mass driver and the incoming space craft with the difference of velocities of a capsule docking at the ISS.

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Re:Water Found Deep Inside the Moon by stcredzero on Friday August 25, 2017 @05:33PM (#15102423)

Ok, you clearly don't understand enough to understand what you don't understand. You don't have to make the velocities or the positions of specific points on the mass driver and the orbit coincide. All you have to do is to make an orbital path coincide with a great circle pathway on the moon. We can already guide spacecraft with this degree of precision. Anyone suggesting that you'd need to make specific point on the mass driver coincide in position and velocity -- that you'd need to brake first -- just doesn't understand what the discussed device is for in the first place. Basically you've just "proved" that you can't land airplanes, because they come in too fast to brake the same 1/10th of a second they touch the tarmac. o_O

If you can't explain my analogy, then I'm just going to conclude you're trolling based on my previously stated disdain for DK syndrome.

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