LRC.Slocum@UTEXAS-20@sri-unix (08/31/82)
From: Jonathan Slocum <LRC.Slocum at UTEXAS-20> How do you control a piece of equipment with a built-in 2 1/2 second MINIMUM reaction time? Answer: not with any reliability at all, in even a moderate environment. And on the moon -- MINING, no less??? As the Navy and other deep-sea operators know, there are lots of situations where remotes do well -- but there are even more where they do not. For most purposes, you've got to be there yourself. That's why there is so much interest in manned deep-submergence vessels, diving tables, and the like. All this, with NO perceptible control delay, and some of the finest equipment money can buy -- at vastly cheaper prices than equivalent capability deposited (intact) on the surface of the moon by any currently available or near-term future means. So don't go staking your claims... -------
REM@MIT-MC@sri-unix (09/01/82)
From: Robert Elton Maas <REM at MIT-MC> When I refer to mining, I really mean just scooping up the surface soil, possibly spilling half of it due to clumbsiness, and dumping it into a hopper for conveyance to the processing station. I have in mind a solar-powered remote-control station on the moon, and a servo based on position (not velocity or pressure). Thus once you are trained, you just visualize where you want it to shovel on the TV image and make the corresponding motion on Earth which takes place on Moon later. You should be able to shovel several scoops of soil in a batch, then go back after seeing what's left and shovel some of the parts you missed. I can walk 10 or 20 steps with my eyes closed and know when I am about to reach a curb I saw back at the start before I closed my eyes. I can reach for objects with my eyes closed providing I've located them beforehand. I can spot all the clutter on my floor, turn off the lights, and then walk across to my bed in the dark, stepping over the clutter I can no longer see. I figure I can locate the places I want to shovel on the moon and then get most of them without visual feedback. At least I'm confident enough I'd like to try the experiment on Earth using artificial feedback delay to prove it could be done on the Moon with real feedback delay.
REM@MIT-MC@sri-unix (09/02/82)
From: Robert Elton Maas <REM at MIT-MC>
Date: 1 Sep 1982 09:08 PDT
From: Ciccarelli at PARC-MAXC
Why the insistence on Earth-based control of the mining machine?
It's simpler to get it working that way. Eventually we want to
automate it. With remote control, we need only solve the problems of
getting the device there and maintaining communication with it. With
automatic control we have to in addition find an algorithm that can
replace a human worker, and debug it. Remember even the Voyager didn't
make its own decisions, we radioed a sequence of commands to it and it
merely executed them by rote. It took days to figure out a change
before we could safely radio it up. We couldn't use interactive
control because (1) too many things had to be done in too short a
time, (2) the radio (speed of light) delay was much more than 3
seconds (more like a half hour each way) making interaction
impossible, (3) motions had to be more precise than a human could do
by servo. On the moon we have plenty of time to stop and retry
something without losing a once-in-a-lifetime chance, only 3-second
total delay, and no need to be especially unclumbsy.
One possible way of positioning would be for the lander unit to shoot out
lengths of fine wire which could be several hundred meters long
and would be energized with a signal which the mining rover could detect.
One more system that can fail. But maybe worth trying the second or
third time.
1) Can a suitable mining area be located from lunar orbit (i.e. do
you need to actually sift the sand or can you use remote-sensing
techniques)?
2) Can a payload be set down in that area with suitable
positioning accuracy?
[I think present art would indicate "Yes" on both counts].
Good questions. Is SSI or anybody working on them? Re accurate
locating, a rover to move from landing spot to work spot would help,
as would a navagation system for the Moon similar to the one currently
planned for Earth, allowing travel to within a couple meters of each
other merely by subtracting coordinates and traveling "toward" each
other accordingly. Anybody working on accurate lunar navigation?