Speaking of Hunchbacked...

[smartcooky]

That's an intriguing story I haven't heard of.

But what about Phobos' low gravity? Its escape velocity is only 11.3 m/s, which means its surface-skimming orbital velocity (assuming a uniform sphere, which it isn't) is 11.3/sqrt(2) = 8 m/s. Were Agent K.15 to reach this velocity along the surface he would literally put himself into orbit, losing all foot traction. Not that it's all that great even when stationary (surface gravity ranges between 2 and 8 mm/s^2 -- that's millimeters per second squared or millinewtons per kg -- so he's not likely to get around very quickly with his feet in any event. He'd have to use some sort of thruster pack with fuel that would be consumed. And he'd have trouble staying close to the surface that's his best protection.

Clarke did address that in the story.

He stood in the center of an irregular plain about two kilometers across, surrounded by low hills over which he could leap rather easily if he wished. There was a story he remembered reading long ago about a man who had accidentally jumped off Phobos: that wasn't quite possible-though it was on Deimos-as the escape velocity was still about ten meters a second. But unless he was careful, he might easily find himself at such a height that it would take hours to fall back to the surface-and that would be fatal.


At the same moment that resourceful individual was taking stock of the situation, which might very well have been worse. He had reached the hills in three jumps and felt less naked than he had out in the open plain.

He was particularly careful not to overtake her on one of his kilometer-long glides,

That last bit takes care of the "footprints" issue raised by Count Zero. Tracking someone by following footprints a kilometre apart in search area of over 1000 sq km would be no trivial task

You can read the whole story here

http://bookre.org/reader?file=210433&pg=1

Its only two pages long.

[ka9q]

The obvious solution is to keep his feet off the ground except when stopped, and pull himself along by his hands.  On Phobos, of all places, this is made easier by the grooves and striations on the surface.

It doesn't seem likely that there would be natural handholds on Phobos. They'd have to handle a lot of force for our fugitive agent to maneuver quickly across the surface. But since we haven't yet been to Phobos, there's no way to know.

Edited to add: I suppose one way to move across the surface is to push yourself horizontally using boulders big enough for their inertia to keep them more or less stationary even if they're just resting on the surface.  Stand on the side of a big boulder (or lay on the ground with your feet against it), slowly crouch down (walking your hands against the surface) and push off horizontally towards another big boulder. Chances are you'll miss it and will have to wait to fall back to the surface so you can slowly make your way to another big boulder and repeat the process.

[Peter B]

All this talk of moving across low-gravity moons reminds me of the Golf Game you can play on Saturn's moons: http://www.ciclops.org/sector6/golf.php?js=1

(I'm not very good.)

[raven]

Neat, but it would be nice if the ball was easier to see. It can be really hard to pick out a lot of the time.

[Zach]

Control jets aren't much quicker, and in any case their use is restricted because the rotation they produce is permanent and they are liable to leave the ship spinning like a slow-motion pinwheel, to the annoyance of all inside."

This one sentence has long bugged me. What's so hard about firing the "control jets" a second time to counteract the rotation caused by the first firing?

Having said that, I understand the slowness with which the spacecraft would orbit such a small asteroid, but if the captain is willing to use his main engine to change orbits, placing the spacecraft where he wants it shouldn't be quite as hard as Clarke makes it.

Precisely, furthermore any rotation initiated by a change in gyro speed will also be permanent, until a countering change is made in the opposite direction. Same problem (or lack thereof) with either method. But it's easy for me to say that after it's been done, whereas Sir Clarke was years ahead of reality