Message-ID: <4Y9W4Gy00UkZIBo055@andrew.cmu.edu>
Reply-To: space+@Andrew.CMU.EDU
From: space-request+@Andrew.CMU.EDU
To: space+@Andrew.CMU.EDU
Date: Tue, 21 Mar 89 05:16:50 -0500 (EST)
Subject: SPACE Digest V9 #303

SPACE Digest                                      Volume 9 : Issue 303

Today's Topics:
			      Re: Sanger
			      Re: Sanger
			      Re: Sanger
			      Re: Sanger
		   Re: Soviet Space Flight Tickets
			Rockoon's (was Sanger)
		Manned vs. unmanned mission popularity
Re: Discovery's return-to-flight photographs record many firsts (Forwarded)
		  Re: babies in space (and 'waldo')
		       Re: Teleoperation delays
		       Re: SPACE Digest V9 #298
----------------------------------------------------------------------

Date: 16 Mar 89 15:36:24 GMT
From: thorin!lhotse!symon@mcnc.org  (James Symon)
Subject: Re: Sanger

In article <78@enuxha.eas.asu.edu>, kluksdah@enuxha.eas.asu.edu (Norman C. Kluksdahl) writes:
> I have done some back-of-the-envelope calculations to check out the
> advantages of speed at release of the orbital vehicle.  (Note:  these
> are only rough calculations, intended only to demonstrate a point).
> 
> In all cases, it is assumed that the payload is released at an altitude
> sufficiently large to neglect most air frictional effects.  . . .

You don't mention the mass ratio for standing start at sea level
(considered common knowledge I suppose, but I'm just a voyeur) but
your numbers suggest to my envelope-back that the benefits of added
speed at launch probably don't warrant the investment in a Mach 5
launch vehicle.

> . . .  Still, air launch does promise something--I read that OSC's
> Pegasus gains about 15% in usable payload by air launch at Mach 0.8. 

And that's still down in pretty thick air, isn't it? So how about Mach 0.0 
at 125,000 ft. under a set of monster balloons?

jim
symon@cs.unc.edu
{decvax uunet}!mcnc!unc!symon

------------------------------

Date: 16 Mar 89 22:41:26 GMT
From: asuvax!enuxha!kluksdah@noao.edu  (Norman C. Kluksdahl)
Subject: Re: Sanger

In article <15877@cup.portal.com>, mmm@cup.portal.com (Mark Robert Thorson) writes:
> >This seems like a better idea than HOTOL or NASP: no need to take the
> >entire vehicle to orbit or to make the first stage capable of flight
> >at extreme hypersonic speeds.
> >
> If I'm not mistaken, the original concept for the space shuttle called for
> a manned, reusable plane to carry the shuttle to an altitude from which it
> could make orbit by itself.
> 
> Wouldn't a re-activiation of this design objective be one of the least
> costly and most safe ways of turning our technological duckling into a
> technological swan?

The idea, while quite noble on the surface, is ignoring one basic fact.
We would have to admit that the shuttle is not the best system possible,
dig up the old designs, then sell them to Congress, which controls the
purse-strings.  Remember Congress?  That's the same group which gave us
the shuttle-as-we-know-it in the first place through budget cutting and
other political tricks, resulting in a less-than-optimal, compromised
vehicle.

A better idea would be, in the words of Henry Spencer, to have a private
vehicle which "embarrassed NASA and the Air Force" by its operation.
I.e., cheap, simple, and reliable.  (Sorry if the quote isn't quite
perfect, Henry! :-) :-) )


**********************************************************************
Norman Kluksdahl              Arizona State University
            ..ncar!noao!asuvax!enuxha!kluksdah

standard disclaimer implied

Useful criticism always appreciated.  Senseless flames always discarded.

------------------------------

Date: 16 Mar 89 21:07:45 GMT
From: asuvax!enuxha!kluksdah@noao.edu  (Norman C. Kluksdahl)
Subject: Re: Sanger

In article <7284@thorin.cs.unc.edu>, symon@lhotse.cs.unc.edu (James Symon) writes:
> your numbers suggest to my envelope-back that the benefits of added
> speed at launch probably don't warrant the investment in a Mach 5
> launch vehicle.
> 
>  So how about Mach 0.0 
> at 125,000 ft. under a set of monster balloons?
> 

I just calculated the theoretical mass ratio, using the same assumptions
as before (i.e. negligibly small air resistance, Isp = 400).  If, at 125K
altitude, the air is negligibly thin, then orbital velocity can be
attained with a mass ratio of (roughly speaking) 5.75.

I agree with your point.  Unless Mach 5 can be attained VERY cheaply, then
it simply isn't worth the cost.  An additional point is that getting a
carrier to Mach 5 at high altitude would either require dual engines 
(i.e. turbojet and ramjet, turbojet and rocket, etc, ad nauseum) or something
akin to an air-turbo ramjet.

**********************************************************************
Norman Kluksdahl              Arizona State University
            ..ncar!noao!asuvax!enuxha!kluksdah

standard disclaimer implied

Useful criticism always appreciated.  Senseless flames always discarded.

------------------------------

Date: 17 Mar 89 03:03:56 GMT
From: cs.utexas.edu!ut-emx!bonin@tut.cis.ohio-state.edu  (Marc Bonin)
Subject: Re: Sanger

> > >
> > If I'm not mistaken, the original concept for the space shuttle called for
> > a manned, reusable plane to carry the shuttle to an altitude from which it
> > could make orbit by itself.
> > Wouldn't a re-activiation of this design objective be one of the least
> > costly and most safe ways of turning our technological duckling into a
> > technological swan?
> ...
> We would have to admit that the shuttle is not the best system possible,
> dig up the old designs, then sell them to Congress, which controls the
> purse-strings.  Remember Congress?  That's the same group which gave us
> the shuttle-as-we-know-it in the first place through budget cutting and
> other political tricks, resulting in a less-than-optimal, compromised
> vehicle.
> 
  Not exactly. Congress , while by no means blameless, did not turn the 
shuttle into a hodgepodge of fiscal compromises.  Blame Dick Nixon, who
got Congress to cut the shuttle budget in half TWICE. 

History shows that the President, not Congress, is the principal architect
of space policy , and that Congress generally gives him the program he wants.
JFK wanted a big space program , he got it.  LBJ carried on the legacy, 
Congress went along.  Nixon didn't want much of a space program and Congress
was quite willing to cut Apollo 18-20, chop the shuttle development budget.

                     Marc Bonin

------------------------------

Date: Thu, 16 Mar 1989 12:44-EST 
From: Dale.Amon@H.GP.CS.CMU.EDU
Subject: Re: Soviet Space Flight Tickets

> Call up who?  Pravda?  The Soviet Embassy in Washington?  The State Bureau
> for Never Lying to the Public?  That's a branch of the KGB.  :-)

No. Call Up Art Dula in Houston. His company is the US sales rep. for
Glavkosmos.

------------------------------

Date: 17 Mar 89 07:32:36 GMT
From: uxc!garcon!pequod.cso.uiuc.edu!ahiggins@csd4.milw.wisc.edu  (Andrew Higgins)
Subject: Rockoon's (was Sanger)

In article <7284@thorin.cs.unc.edu>, symon@lhotse.cs.unc.edu (James Symon) 
writes:

> your numbers suggest to my envelope-back that the benefits of added
> speed at launch probably don't warrant the investment in a Mach 5
> launch vehicle.
> 
> So how about Mach 0.0 
> at 125,000 ft. under a set of monster balloons?

This idea of a "rockoon" has been around for quite a while.  It was 
pioneered by Dr. James Van Allen (forgive me, Henry) in 1952 for cosmic ray 
research.

In 1957, the Air Force fired a series of balloon-suspended rockets into 
space.  Known as Project Farside, the experiments were a pioneering 
achievement and succeeded in setting an altitude record which remained 
unbroken even after Sputnik I.

The Farside vehicle was lifted to an altitude of 100,000 ft by a large 
helium-filled polyethylene balloon.  The rocket itself consisted of four 
solid fueled stages (Thiokol Recruits and Arrow II's) with a small (4 X 6 
inches) payload package.

The six Farside tests were conducted from the remote Eniwetok Atoll (yes, 
the same as the first megaton H-bomb test) at the Marshall Islands in the 
Fall of 1957.  The balloon-rocket assembly took two hours to rise to the 
designated altitude.  The rockets were spectacularly launched *through* the 
balloon (the Air Force captured some impressive ground based pictures).  
Because the rocket was already above 90% of the Earth's atmosphere, the 
vehicle was allowed to accelerated at a rate which would burn up a similar 
ground launched vehicle.  The total duration of powered flight was around 
30 seconds.

Unfortunately, the rocket traveled too fast for radar tracking, so altitude 
was judged by crude optical and radio means.  The highest officially 
recorded altitude was 3,100 miles, although the vehicle could have easily 
reached 4,000 miles.

The payloads on the Farside rockets were alternated between magnetometers 
and Geiger counters.  Had the most successful Farside launch carried a 
Geiger counter rather than a magnetometer, it very likely would have 
discovered the Van Allen radiation belts.

More elaborate plans were drawn up for Farside II, which would have been 
able to deliver a payload to the Moon, thus living true to its name.  
Farside II, however, was not able to compete with the Thor Able Moon 
rocket, which was chosen for the job in January 1958.  Farside II never got 
farther than the design stage.

After the IGY, larger rockets became more accessible, and the ideal of 
balloon launched rockets slipped out of vogue, with the exception of a 
single Japanese firing in 1961.  The Japanese continue to use balloons to 
test launch scaled models of the H-II.
--
Andrew J. Higgins	             | Illini Space Development Society
404 1/2 E. White St apt 3            | a chapter of the National Space Society
Champaign IL  61820                  | at the University of Illinois
phone:  (217) 359-0056               | P.O. Box 2255 Station A
e-mail: ahiggins@pequod.cso.uiuc.edu | Champaign IL  61825
                 ^^^^^^
"When the Waters were dried an' the earth did appear,...The Lord He created
 the Engineer"
 - Rudyard Kipling

------------------------------

Date: Fri, 17 Mar 89 10:11:21 PST
From: Peter Scott <pjs@aristotle.Jpl.Nasa.Gov>
Subject: Manned vs. unmanned mission popularity

Noticing the attention in the media to the shuttle mission, and the comments 
from the politicians (such as Bush's recommitment to the space station), I
have to wonder about the unknowable value to the space program that this
constitutes, and compare it to what I've seen for unmanned missions: were the
first encounters with the planets Saturn and Uranus the banner items on the
network news?  Did they prompt talk from politicians about specific missions
that should be funded?  Oh, I know talk is cheap on Capitol Hill, but it's
a step up from silence.

With the attention that Y.A.S.M. (yet another shuttle mission) gets from the
public, it doesn't seem likely that carrying out unmanned but economical
missions until we can "afford" manned missions would be a viable strategy,
because of the precipitous drop in support ("Why should we give you money
for lunar colonies when you're just going to spend it on an asteroid sampling
mission?") it would engender.  Note that this does not translate into an
endorsement of the U.S. space shuttle.

Peter Scott (pjs@grouch.jpl.nasa.gov)

------------------------------

Date: Fri, 17 Mar 89 10:41:08 PST
From: Peter Scott <pjs@aristotle.Jpl.Nasa.Gov>
Subject: Re: Discovery's return-to-flight photographs record many firsts (Forwarded)

orion.cf.uci.edu!dkrause@ucsd.edu  (Doug Krause) writes:

>In article <22768@ames.arc.nasa.gov> yee@trident.arc.nasa.gov (Peter E. Yee) writes:
>>     As a result, the STS-26 photographs captured details not 
>>usually seen in Shuttle photography: for the first time, an 
>>aircraft was photographed generating a contrail; individual 
>>buildings could be seen in the Canary Islands; a line of 
>>electrical transmission pylons was seen in southern Sudan; and 
>>oil platform flares were seen in the Gulf of Campeche.

>Could these be seen without the cameras?  I ask because we've
>all been told that the Great Wall is the only manmade object
>visible from space.

Depends how good your eyesight is... 8-)

I don't know how the Great Wall thing got started, but I'm sure that you
need a telescope to see it, in which case the field is wide open.

pjs@grouch.jpl.nasa.gov

------------------------------

Date:         Fri, 17 Mar 89 07:30:14 EST
From: Eric Harnden <EHARNDEN%AUVM.BITNET@VMA.CC.CMU.EDU>
Subject:      Re: babies in space (and 'waldo')

this, like other input on the subject, has no direct bearing on human
embryo development, but is interesting: i understand that frog eggs,
or some order like that, will develop on their own into (haploid?..
one set of genes) animals, if pricked with a pin, and that their
orientation is determined by the position of the rupture.

yes, the name 'waldo' will have to stick... after all, they're already in
use. devices controlled by remote communications have the hobbyist's name
of RC, and that might well become the functional term for what's being
described. it really all depends on what the people who are building  the
things do with their spare time.. that often is the source for new
nomenclature (i mean.. 'quarks' for crying out loud!). the name 'waldo'
comes from robert a. heinlein, and was the name of the central character
in the story of the same name, about a paralyzed man who invents the device
for his own use.
more to the point... i think that it's inevitable that such things will come
into use, and i'm not really sure why there is a 'debate' for mr. minsky to
reply to... but i think that, while his data is of course correct, there is
a point missing. the delay time is real, and has one of two possible results.
the delay will either require that the operator think D time ahead (where D
is the *cumulative* roundtrip delay), which may be possible for simply driving
a motorized device across a land/station-scape, or, when the imprecision
inherent in such a mode is unacceptable, will have to wait D time between
initiation of each step in a movement task. this waiting will be of such an
order as to allow the operator to relax his concentration between each command,
without actually having time to think about anything else. this sort of stop-go
in his head will have the same effect that it does driving in city traffic:
fatigue will set in quickly. how might we reduce its' effects?

Eric Harnden (Ronin)
<EHARNDEN@AUVM>
The American University Physics Dept.
(202) 885-2758

------------------------------

Date: 18 Mar 89 05:04:26 GMT
From: mailrus!eecae!netnews.upenn.edu!grasp.cis.upenn.edu!ulrich@tut.cis.ohio-state.edu  (Nathan Ulrich)
Subject: Re: Teleoperation delays

In article <Added.kY8E0yy00Ui38LWE9t@andrew.cmu.edu> EHARNDEN@AUVM.BITNET (Eric Harnden) writes:
>the delay time is real, and has one of two possible results.
>the delay will either require that the operator think D time ahead (where D
>is the *cumulative* roundtrip delay), which may be possible for simply driving
>a motorized device across a land/station-scape, or, when the imprecision
>inherent in such a mode is unacceptable, will have to wait D time between
>initiation of each step in a movement task.
>Eric Harnden (Ronin)
><EHARNDEN@AUVM>
>The American University Physics Dept.
>(202) 885-2758

There is at least one other possibility, one that my advisor, Richard Paul,
is working on with some of the students in our lab.  If we can design a
system that can model the environment and display the situation as it will
appear D time in the future (a kind of high-tech astrology), then the operator
can be dealing with tasks *as they happen*, albeit in this "virtual world"
we have created.  The system will display the predicted future on a video 
screen, and the operator will respond to it, just in time for his commands to
reach the real situation after the communications delay.

Obviously, this approach is only as good as the accuracy of the predictions,
but it hopefully will recognize and wait when something outside of its realm
of expertise or knowledge appears.  And the longer the delay D, the more likely
the virtual world to be wrong.  But for delays of a few seconds, and many of
the repetitive and simple tasks expected, this could be a great help.

I'm not directly involved with the project, but I'm following its progress 
with interest.  They are initially using a smaller domain, a small robot
arm and a linked graphics model on an IRIS that matches it exactly, kinemat-
ically and dynamically.  Preliminary results are encouraging.

Nathan Ulrich
ulrich@grasp.cis.upenn.edu

------------------------------

Date: Fri, 17 Mar 1989 13:04-EST 
From: Dale.Amon@H.GP.CS.CMU.EDU
Subject: Re: SPACE Digest V9 #298

Scott Henry:

So we are back to the situation of having a tether crossing the event
horizon which can remain intact, cannot transmit information and cannot
be retracted, or at least so I would presume. This is getting messy...

------------------------------

End of SPACE Digest V9 #303
*******************