From: arnold@clipper.ingr.com (Roger Arnold)
Newsgroups: sci.space
Subject: Re: With telepresence, who needs people in Earth orbit?
Summary: Let's stop confusing the issues.
Date: 1 Sep 92 19:39:08 GMT
Organization: Intergraph Advanced Processor Division - Palo Alto, CA

In article <1992Aug28.123432.16321@iti.org>, aws@iti.org (Allen W. Sherzer) writes:
> In article <1992Aug28.084645.28803@mullet.gu.uwa.edu.au> phew@mullet.gu.uwa.edu.au (Phew) writes:
> 
> >Depending solely on telepresence in space would limit human intervention to
> >any reasonable "real time" sense to about the Moon or so...
> 
> Using only telepresence is limited not only to distance but also to scale.
> The available bandwidth is limited and telepresence in any realistic sense
> will use up a lot of it.
> 
>     Allen

Not to pick on Allen, in particular; his just happened to be the message
I was reading when my irritation level over this whole thread crossed
the posting threshold.  Actually, his statement is technically correct.
It's the implication that I object to.

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.  

Just so people know where I'm coming from, I'll note that I grew up 
on on the writings of Heinlein, Clark, Willey Ley, Dandridge Cole, 
and other visionaries of that generation.  I believe in the critical
importance of getting human beings off the planet and into space.  But
I'm totally disillusioned with NASA and the manned space program as a
route to that end.  I wish Goldin the best of luck in reforming NASA,
but pardon me if I don't hold my breath.

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.  But it's unrealistic to expect that to happen.  
And probably just as well, when you consider the politics behind the 
building of those wonderful cathedrals.  In any case, barring a really
drastic change in the social climate, any human move into space will
have to be economically motivated.  Otherwise, it just won't happen.  
We will see large numbers of people living and working in space when--
and only when--it makes economic sense for them to be there.  And it 
*will* eventually make sense, if we can get the level of commercial 
activity high enough and the cost of transportation low enough.

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.  A
teleoperated research facility in low earth orbit would find no short-
age of commercial customers.  If they only had to pay for delivery of 
small quantities of material and a share in amortization of the equip-
ment in orbit, it would be a bargain.

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.  It's easiest if the
orbit is equatorial, and so what if that means using Pegasus or Ariane
for launches?  But it's not much harder with an inclined orbit.  You
need a number of downlink receiver sites, linked by high-bandwidth 
fibre optics to the operation center.  And probably three operations
centers on different continents that hand off control on 8-hour shifts.  
The longest round trip time delay for teleoperation is only 150 
milliseconds.  That happens when the station is on the opposite side 
of the earth from the active operations center.  For most of each 
orbit, the delay would be under 100 milliseconds.  At that level of
delay, force feedback is quite manageable. 

Obviously, there are limits to what you can do with telepresence from
earth.  That doesn't mean that what you *can* do isn't worth doing.

--
Roger Arnold
arnold@clipper.ingr.com
Xref: sparky sci.space:12391 news.answers:2754