From: utzoo!decvax!cca!MINSKY@MIT-OZ@sri-unix
Newsgroups: net.space
Title: Lunar Telepresence
Article-I.D.: sri-unix.3157
Posted: Tue Sep  7 21:36:52 1982
Received: Wed Sep  8 04:12:27 1982

From: Marvin Minsky 
The effect of time-delay on remote manipulation will depend on
the time-scale of what you are manipulating.  The human sensory-motor
reaction loop is of the order of 1/5 of a second.  As you know,
things fall 16 feet in the first second, and there's a square-root
scaling for that.  So you can catch something that falls out of your
hand in half a foot or so.

The lunar gravity is about 1/7th ours.  The lunar round-trip time
delay is about 12/5 seconds, and if we add our own delay we get 13/5.
So if you consider gravity scaling, then lunar teleoperation should be
sort of like you are twice as slow as here!  That is, you ought
to be able to catch something before it falls two feet.

Now, we will be building lunar structures that are large, because of
the low-G.  Perhaps they'll be 4 times as high, and yet use weaker
materials!  Then you can catch them just the same as here - when you
scale everything!  How's that for an optimistic way to look at it?

Seriously (but I was, actually), most space-structure work will use
very delicate materials.  That, after all, is the great thing about
building stuff out there.  Then, the manipulation speeds will be
limited, not by reaction time but by the gentleness needed for
handling.  You simply cannot accelerate those aluminum-foil girders
very much or they will bend and crinkle.  So space teleoperation will
not suffer from delay very much, because you will have to plan your
motions many seconds ahead, or even minutes, to avoid collisions.  If
you jerk to avoid an unexpected collision you might do more harm than
good abyway.

Finally, of course robotic AI systems can work fast locally.  If you
want to take your analog wrist-watch apart it will take a long time,
by remote control, but presumably such tiny work will be the exception.

Epilogue: it infuriates me that there seems to be still no substantial
research on telepresence.  There are a few little projects here and
there, but none of much significance.  Still, no one seems to be
fabricating a decently humanoid remote hand, either.  Foo on the U.S.
if some other culture  beats us on this, another of the obviously
enormous industries of the not far-away future that we will miss out on.

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