From: roberts@CMR.NCSL.NIST.GOV (John Roberts)
Newsgroups: sci.space
Subject: Re: Teleoperation
Date: 3 Sep 92 12:54:40 GMT
Organization: National Institute of Standards and Technology
	formerly National Bureau of Standards


-From: arnold@clipper.ingr.com (Roger Arnold)
-Subject: Re: With telepresence, who needs people in Earth orbit?
-Date: 1 Sep 92 19:39:08 GMT
-Organization: Intergraph Advanced Processor Division - Palo Alto, CA

-Many space activists appear to view telepresence as a threat to a
-cherished and beleagured manned space program.  Most of the discussion
-here has been cast in a "manned vs." context.  So a lot of diversionary
-non-issues get tossed about: "it can't do everything", "it's limited by
-time lag", "it's limited by bandwidth".  Plus the biggest confusion
-factor of all: failure to distinguish between teleoperation and robotics.
-It's easy to make telepresence look bad or difficult if you can get away
-with discussing it in terms of the capabilities of autonomous robots.  

Fortunately, NASA is still working on telepresence and teleoperation. I
don't know the exact level of spending, and no doubt it would be nice if
it were higher than it is, but it's considerably better than ignoring the
subject entirely. I believe one of the cost-cutting measures for SSF was
to have the external robots operated largely from the ground rather than
exclusively by the astronauts on the station.

I would say that the subject line chosen isn't very useful if you want
to discuss constructive cooperation between humans and robots in space.

-If it ever did, western culture no longer has the will or vitality to 
-move into space in pursuit of a vision.  Sure, if we applied the same 
-fraction of GNP that went into building cathedrals in the Middle Ages, 
-or the pyramids in ancient Egypt, we could easily support lunar and 
-Martian colonies.  

That's a pretty harsh accusation, and I think you're exaggerating. I don't
know about ESA, but the US is still working at it. Remember that many of the
cathedrals took on the order of a century to complete - the US has only been
really working on the space program for 30 years or so. Many space
enthusiasts are more impatient than that - they think that space colonies
could be built with something like the level of effort required to build
a local K-Mart, or else that we should speed things up by throwing hundreds
of billions of dollars a year at the problem. As has been shown by previous
missions, doing things in space is actually quite difficult compared to 
doing them on the ground - anything that's actually been done has been
much harder than the wilder visionaries had thought. Current public support
for the civilian space effort seems to be around $15-20 bilion a year. As
Allen has pointed out, that's enough to eventually get quite a lot accomplished
if you spend it wisely, or even if you only spend part of it wisely. As you
point out, a large commercial interest could speed things considerably. Part
of what NASA's mission is to develop or encourage the development of space
technologies and markets that will attract private enterprise.

-I see telepresence not as competition to manned space activity, but 
-as a bridge to the level of space activity that will be necessary to
-bring costs down and make it worth building real space stations.  

Sounds reasonable.

-Most of the objections to teleoperation that people raise, or the
-problems that they posit as standing in the way, are easily avoided.
-It's absurd to tie teloperation in low earth orbit to a communication
-path involving two round trips to Clark orbit.  Build a necklace of
-co-orbiting microsats to relay signals from the facility to whichever
-satellite is currently in position to downlink.  

NASA wanted to build such a network several decades ago, and was overruled.
It would be pretty expensive now to set up such a network just as a
precursor to teleoperation. Much better to develop and demonstrate it with
the current communications system, then make a decision on whether to
change the communications. (Would Iridium work for this type of application?)

I've had a chance to play with the lunar delay simulator that Bill Higgins
has written about. It's surprisingly easy to learn - with about two minutes
of training, you can drive the robot around, use it to pick up and move
objects, etc. No doubt a trained operator could do better. Except for 
applications that require the application of momentum (i.e. swinging a hammer
or driving a bulldozer through a pile of dirt), and applications that require
rapid response (i.e. cat juggling), the main effect is that operation is
greatly slowed down. But even with a slowdown of 10-20 times teleoperation
could be more economical than doing the same work with humans in space,
provided that it can be done at all with teleoperation.

Other challenges to near-term use of teleoperation:

 - A video display uses up a lot of bandwidth, and provides a lot less
   visual information than seeing the object in person. One thing that can
   help tremendously with this is true 3D or stereo imaging, using two
   cameras side by side. The currently popular way to display it is with
   alternating frames on a conventional video monitor, with liquid crystal
   shutter goggles to separate out the views to the two eyes. Doing this
   in the NTSC format (a pair of views every 1/30 of a second), flicker
   isn't really a problem if the light levels aren't too high. Faster
   refresh rates of course are possible if you have the bandwidth. The
   JPL people working on the small Mars rovers use this kind of 3D imaging.

 - Aside from feedback delay, most currently available remote-control
   general-purpose robots don't have particularly great dexterity and strength.
   Improving the strength shouldn't be too hard, but dexterity is very
   tricky - we're a long way from what humans can do, even in EVA suits.
   But there is progress - I saw some interesting robot hands at Bell Labs
   in Holmdel.

 - Sophisticated robots are among the most complicated mechanical devices
   around, and not particularly reliable even on Earth. In space, mechanical
   devices seem to break down even more easily. Building a teleoperated
   robot that can manipulate its environment isn't too difficult, but 
   building one that can be used effectively to repair another robot of the
   same kind is a much more difficult task. When the robots start to break
   down, it can be very useful to have humans nearby to repair them. (This
   would apply to a space station, for instance, where humans are already
   present.)

John Roberts
roberts@cmr.ncsl.nist.gov