Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V15_6/V15NO631.TXT

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Date: Tue,  5 Jan 93 05:06:10
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #631
To: Space Digest Readers
Precedence: bulk


Space Digest                Tue,  5 Jan 93       Volume 15 : Issue 631

Today's Topics:
                  asteroids beyond Jupiter (2 msgs)
                          Dante Advisory #4
                          Dante Advisory #5
                          Galileo's antenna
         How many flights are Orbiters designed for? (2 msgs)
       Let's be more specific (was: Stupid Shut Cost arguement
                         Nasa flight sim code
      Shuttle a research tool (was: Re: Let's be more specific)
                       SSTO vs 2 stage (2 msgs)
        Stupid Shut Cost arguements (was Re: Terminal Velocity
           Terminal Velocity of DCX? (was Re: Shuttle ...)

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

Date: 4 Jan 93 16:26:29 GMT
From: Dave Stephenson <[e-mail]>
Subject: asteroids beyond Jupiter
Newsgroups: sci.space

[e-mail] writes:

>In article <1992Dec2t.edu> <3342.29953@[e-mail]>,
>billn@[e-mail] (bill nelson) writes:
>
>> My definition of asteriod is: any body that orginated in the
>> "asteriod belt" (between Mars and Jupiter). I have made no claim as to
>> where they can orbit. Jyonder is large enough to cause significant
>> perturbation to their orbits.

>Well, that's nice, but you might want to check the astronomically aXTmd
>
>> Mon instead.  And just how do you propose to define origins here?
>Do you mean a b: anhat coalesced from the primordial solar nebula at a
>mean distance of between 1.4 and 5.2 AU from the center of that neolar ?
>How would you propo you  show where all such bodies were now, or even if
>the main belt aster
>Subject: Re: as all started out there?

>> However, it is a long way from Jrbit.r to Neptune. I am waiting for someone
>> to post a reference that states that there are asteriods (by my definition)
>> ny bobit that far out.

>So who the heck are you?  President of the International Ack thmical Union?
>When Charlie Kowal discovered Chiron it was classed as an asteroid, and it's
>orbit takes it well past Saturn.  Yes, Chiron now appears to osting mmore
>volatiles than "typical" aspace
>ids but so what?

>-Bill Gawne,  Space Telepace Te Science Institute
>#!

Now that you mention Chiron, could someone give me a few references
to popular articles on Chiron. I know a space artist who wants to
paint as it in its outgassing phases. Sky and Telescope articles would
be ideal. He wants to make the painting realistic.
Thanks.
--
Dave Stephenson
Geodetic Survey of Canada
Ottawa, Ontario, Canada
Internet: [e-mail]

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

Date: 4 Jan 93 17:52:20 GMT
From: Greg F Walz Chojnacki <[e-mail]>
Subject: asteroids beyond Jupiter
Newsgroups: sci.space

>>In article <1992Dec2t.edu> <3342.29953@[e-mail]>,
>>billn@[e-mail] (bill nelson) writes:
>>
 My definition of asteriod is: any body that orginated in the
 "asteriod belt" (between Mars and Jupiter). I have made no claim as to
 where they can orbit. Jyonder is large enough to cause significant
 perturbation to their orbits.
>
Correct me if I'm wrong, but was the original poster intersted less
in terminology than whether an object in the "main" asteroid belt
could be perturbed into an orbit like, say, Chiron's? If so, I
don't know the answer (I suspect it's yes), but it's an interesting
question.

(I'm just trying to put out misdirected flames.)

Greg

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

Date: Mon, 4 Jan 1993 16:35:00 GMT
From: Ron Baalke <[e-mail]>
Subject: Dante Advisory #4
Newsgroups: sci.space,comp.robotics

Charles Redmond
Goddard Space Flight Center
Greenbelt, Md.                     Jan 1, 1993
(Phone:  [phone])

DANTE ADVISORY #4

As of 8:35 pm January 1, the Dante robot was suspended about
21 feet below the crater rim at Mt. Erebus, Antarctica,
while the project team there reset the computers which
operate the robot's depth-perception and walking systems.

The robot had been successfully "launched" from its
stationary position at the top of the 750-foot deep crater
at about 2:00 am EST January 1 and had begun crawling down
the 40-degree incline towards the crater floor, suspended by
a critical support cable being reeled out by the robot
itself.

The computer reset was required because of activities which
had occurred the day before when both the Antarctic Erebus
"hut" computers and the remote computers located at the
Goddard Space Flight Center Dante payload control room were
both in communication with and controlling the robot.  This
"telerobotic" operation is one of the major objectives of
this joint NASA-National Science Foundation demonstration
project.

The Goddard computer connection was lost as a natural
consequence of losing the satellite connection through the
Tracking and Data Relay Satellite-West.  The satellite
communications between Antarctica and Goddard are scheduled
for pre-set periods each day.  The computer network connects
the Erebus computers and enables them all to function as a
distributed computing system.

In the Antarctic location there are several of these
computers, some of which are located in the operations hut
about 1.5 miles away from the volcano's rim, and one which
is located right on the rim.  When communications are
established between Antarctica and Goddard through the TDRS
satellite, the Goddard computers are added to the robot
network.

COMPUTER PROBLEM DESCRIBED AS COMMON

James Osborn, the Goddard-based Erebus project manager from
Carnegie-Mellon University's Robotics Institute, said this
type of computer problem is quite common in universities and
is easily fixed now that the team is aware of the problem.

Fixing this situation, Osborn said, is a simple matter of
resetting all the computers.  In the case of the one located
on the rim, Eric Hoffman, a member of the Carnegie-Mellon
team located at the Mt. Erebus site, would have to actually
go to the rim since the team believed their attempts to
reset the computers using software were not adequate.

Osborn said the Antarctic team was expecting to have this
problem fixed sometime between the last communications with
Goddard at 8:35 pm EST Jan. 1, and the first communications
session scheduled for Jan. 2 at 1:30 pm EST.  Dave Lavery,
the Erebus program manager also located in the Antarctic,
expected the team to have advanced the robot's position
several more hundred feet lower into the crater by early
afternoon on Saturday, Jan. 2, Eastern Time.

An earlier problem with the robot's tether reel mechanism
had delayed the launch of the robot yesterday and was
finally resolved when the Erebus team members decided to
physically modify the mechanism by removing a portion of the
winding system.

REEL MECHANISM WAS STICKING DUE TO COLD

The reel mechanism is very much like the reel on a fishing
rod and has a device which moves back and forth like a
bobbin to lay the reel smoothly onto the spool.  The
"bobbin" had been sticking because of the very cold
temperatures.  The Erebus team had sprayed lubricant on the
mechanism in several attempts to get it to operate smoothly,
but ultimately removed it completely.

Dave Lavery said this would present no problems to the
descent and bottom-of-the-crater exploration phases of this
project because the tether was properly tensioned and wound
smoothly.  It was only the rewinding of the tether onto the
reel which presented a possible problem.  Lavery said the
team understood the risk of this possibly inhibiting the
robot's safe return up the crater wall but was willing to
accept the risk to get the descent and exploration phase
underway.

The current schedule according to both Lavery and Osborn
calls for a two-and-a-half day descent and exploration phase
beginning at approximately 2:00 pm EST today and lasting
through Sunday, January 3.  During this period the robot
will descend down 70- to 90-degree slopes on the volcano's
inner rim wall and will traverse across about 150 feet of
crater floor to a molten lava lake.

PROJECT IS DEMONSTRATING NEW EXPLORATION CAPABILITIES

NASA and the National Science Foundation are undertaking
this demonstration project to develop technology and
telecommunications capabilities which NASA could use in
future explorations of the Moon or Mars and which the NSF
might apply to its ongoing research activities in the
Antarctic.  Part of the test involving the transfer of
control of the robot from the Mt. Erebus team to team
members located at a payload control center at Goddard was
successfully tested yesterday, Dec. 31 Eastern Time.

Carnegie-Mellon University and the New Mexico Institute of
Mining and Technology are partners with NASA and the NSF as
robotics and volcano experimenters for this project.
Carnegie-Mellon has four team members located on the
Antarctic ice and an additional five team members located at
the Goddard payload control center as part of this project.
New Mexico Institute of Mining and Technology has two
members associated with this project and two members
associated with an allied project on the ice for the Erebus
demonstration.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Choose a job you love, and
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | you'll never have to work
|_____|/  |_|/       |_____|/                     | a day in your life.

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

Date: 4 Jan 93 16:38:00 GMT
From: Ron Baalke <[e-mail]>
Subject: Dante Advisory #5
Newsgroups: sci.space,comp.robotics

Charles Redmond
Goddard Space Flight Center
Greenbelt, Md.                        Jan 2, 199
(Phone:  [phone])

DANTE ADVISORY #5
(all other things being, equal, the FINAL Dante Advisory)

At 5:10 pm Eastern Standard Time Saturday, January 2, the
Erebus project team located on the ice at the foot of the
Mt. Erebus volcano in Antarctica called off any further
exploration by the 8-legged rappelling robot Dante because
of a physical break in the fiber optical cable which
connects the robot with the computers providing its machine
intelligence.

The team reported the results of a day's troubleshooting
during a one-hour-long video conference which included their
colleagues located at the remote robot control site at the
Goddard Space Flight Center in Greenbelt, Md.  The
conference was called following what had been a series of
seemingly minor problems which had cropped up during the
past two days in attempts to deploy the robot down the 750-
foot deep, nearly vertical incline, from the rim of the
continuously active volcano to the lava lake below.

At the time the team called off any further mission
operation, the robot Dante remained suspended approximately
21 feet below the rim of the crater having been successfully
launched yesterday.  Dante had moved the 21 feet on its own
during initial testing of the robot control mechanisms and
had been halted in its further progress by what, at the
time, seemed to be computer network problems.

The team reported that further trouble-shooting of the
computer network problem disclosed kinks in the fiber
optical cable which connects the sensors and motor
mechanisms of the robot with the computer systems which
provide Dante with a depth perception capability and a self-
navigation capability.  The team, in examining the fiber
optical cable kinks, caused a break which stopped all
communications between the robot and the controlling
computers.  In this passage, transmitted from Antarctica
early this morning Eastern time, Dave Lavery, the project
supervisor and the NASA telerobotic program manager, reports
how this situation arose:

"By late in the afternoon, the problem had been isolated to
the fiber optic cable which stretches between the robot and
the control station two kilometers away.  It was found that
the passive deployment system which releases the fiber from
the robot as it walks had formed multiple kinks in the fiber
which had reduced data communications to the robot.  At 1955
hours, while removing the fiber optic cable from the
deployment mechanism, the fiber was severed entirely,
cutting off all communications with the robot.  Without
integrity in this cable, the robot cannot operate."

During the conference today, the Erebus project team located
in Antarctica indicated they have a rescue plan for the
robot Dante which the team simulated in practice sessions
held in Pittsburgh before their arrival in the Antarctic on
Dec. 15.  This rescue plan calls for using the Dante robot
carrier Geryon to hoist the robot up from its current
position to the top of the volcano rim.  From there, the
team will place Dante on Geryon and then move back down the
approximately 1.5 miles from the rim to the base camp.

Once at the base camp, Dante and Geryon will be disassembled
and placed into the shipping crates which were used to get
them from Pittsburgh to the Antarctic.  The rest of the base
camp will be similarly broken down and prepared for shipment
back through McMurdo Sound station.  The team estimated that
the rescue of the robot to the rim position could take from
one to two days beginning tomorrow, Sunday, Jan. 3 Eastern
Time.  The trip down the mountain to the base camp could be
done in one or two days, depending on local weather
conditions.

The team must also break down the communications gear and
antenna which allowed for transmission of video and computer
data through the Tracking and Data Relay Satellite and the
computers which are presently located in the base camp hut.
This process could take as much as five days.

The team reported that one of the considerations in their
decision to call the demonstration project off at this point
was the time period remaining until they must leave the side
of the volcano.  By January 15 the team has to be back at
McMurdo station because of impending ice-up of the Ross Sea
and a worsening of general weather conditions.  This time
constraint has existed all along but became of higher
importance when the break in the fiber optical cable
occurred.

The team indicated they had contacted McMurdo Station and
determined that a replacement fiber cable was not available,
nor were connectors for this type of cable which might have
allowed for a repair operation of this cable.  The
supporting team at the Goddard payload operations control
center was able to find a supplier for identical cable but
could not guarantee delivery of that cable to the Antarctic
in time to make the repair, perform the rest of the descent
down into the volcano and still get the robot back up to the
top and pack everything up in time to depart on January 15.

Dave Lavery said during the conference that the team
considered the project an "unqualified success" in one of
the three primary objectives, that of testing the remote
control of a robot.  The Carnegie-Mellon University team
located at Goddard had successfully commanded the Dante
robot the previous day while the robot was poised at the rim
awaiting its deployment into the volcano crater.

The robot demonstration project had three objectives: to
test telerobotic capabilities; to test the use of such
sophisticated hardware in a very harsh and demanding
environment; and to test the use of advanced computer
programs which would enable machines such as the Dante robot
to act under a form of machine intelligence.  According to
Lavery, the first two objectives of this experiment were
met.  The robot never got to a point where it was under
operation of its own autonomous control systems.

NASA and the National Science Foundation undertook this
demonstration project to develop technology  and
telecommunications capabilities which NASA could use in
future explorations of the Moon or Mars and which the NSF
might apply to its ongoing research activities in the
Antarctic.

Part of the test involved transferring control of the robot
from the Mt. Erebus team to team members  located at the
Goddard payload control center.  This  portion of the
project tested the "telepresence"  capabilities of such
robots for future NASA exploration  missions and is the
portion of the demonstration which was tested and called an
unqualified success.

Carnegie-Mellon University and the New  Mexico Institute of
Mining and Technology are partners with  NASA and the NSF as
robotics and volcano experimenters for  this project.  Team
members from Carnegie-Mellon were located both in the
Antarctic and at Goddard.  New Mexico Tech members were
located at the Mt. Erebus portion.  The robot included six
different sensors which were to have provided significant
and new date about the physical and chemical composition of
gasses and aerosols being released into the atmosphere by
the Mt. Erebus volcano.

The following sets of quotations come from the video
conference which began at 5:10 pm EST Saturday, Jan. 2, and
represent the comments from the team leader, Dave Lavery,
and the two co-principal investigators of this project --
Professor Phillip Kyle, representing the science side of the
project and William "Red" Whittaker, representing the
robotic side of the project.

David Lavery, NASA Telerobotics program manager:

"There is obvious disappointment over what is a component
failure, but we're proud of what we've accomplished.  We've
gone further than anyone said was possible and much farther
than anyone said we would get.

"We've made tremendous progress and compressed five years of
work into one year.

"The mission is an unqualified success in terms of the
telerobotic aspects.  The robot works.  The prototypes are
worthy contenders for inclusion in any further planetary
exploration.  The aspects of sending autonomous robots on
planetary exploration mission has been proven as well.

"We were given in January 1992, when we started this
project, odds of about 20 percent of probably successful
completion.  This was a very, very risky venture.  This has
been a true adventure.  Our spirits remain undaunted."


Phillip Kyle, New Mexico Inst. of Mining and Tech. and co-
principal investigator:

"This has whetted the appetite of volcanologists everywhere.
This was the ultimate challenge.  There is no more nastier
volcano.  It has been a remarkable achievement.

"I think of this as one small step and expect we will be
seeing robots exploring inside volcanoes around the world in
a few years.

"This demonstration project showed we could integrate
science into a robot."


William "Red" Whittaker, Carnegie-Mellon Univ. and co-
principal investigator:

"We are calling it off because of a fiber optical cable

break for which we have no workaround.

"The achievement has been tremendous.  We've written over
150,000 lines of new software code.  We've used the ground
station for the first time.

"This has been a dream program.  It was inspirational work
and I'm really proud of what we've done.  We've made a bold
leap and pushed this technology from the laboratory into the
real world.

"This is just one example of what must be thousands of
similar applications.  This was the real thing.  This robot
left the laboratory and had a real job with a real science
customer.

"We've learned a great deal during this experience in
Antarctica, especially about self-reliance and ingenuity.

"This has really been a dream year.  It called for the best
in a lot of people"



Participants in the conference from Antarctica
were the following individuals:

David Lavery, NASA Headquarters
Steve Thompson, NASA Goddard Space Flight Center
William Whittaker, Carnegie-Mellon University
Eric Hoffman, CMU
Dan Christian, CMU
David Wettergreen, CMU
Phillip Kyle, New Mexico Institute of Mining and Technology
Nelia Dunbar, NMIMT
Bill Macintosh, NMIMT
Sara Krall, Antarctic Support Associates-National Science
Foundation
Ken Sims, ASA-NSF

Participants located in the temporary robot control center
at Goddard during this conference:

James Osborn, Carnegie-Mellon University
Paul Keller, CMU
Jay West, CMU
Chris Fedor, CMU
Jim Christo, NASA Goddard Space Flight Center
Bob Rodriguez, NASA GSFC Bendix Field Engineering Company
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Choose a job you love, and
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | you'll never have to work
|_____|/  |_|/       |_____|/                     | a day in your life.

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

Date: Mon, 4 Jan 1993 17:59:00 GMT
From: Ron Baalke <[e-mail]>
Subject: Galileo's antenna
Newsgroups: sci.astro,sci.space

In article <[e-mail]>, [e-mail] (David O Hunt) writes...
>Is there anyway of telling that the hammering is making progress (aside
>from rib release)?

The sun sensor and wobble measurements are the two main indicators.  The
shadow of the antenna falling across the sun sensor is used measure the extent
the antenna is open.  Since the stuck ribs cause the antenna to be
more open on one side than the other (asymmetrically deployed) and the
spacecraft is spinning, a slight wobble exists which can be measured.
Also, when the antenna is fully open, a couple of switches will be activated.
After the first antenna hammering last week, the sun sensor and wobble
measurments indicated a change in the antenna, the first change measured
since the initial antenna deployment attempt in April 1991.  The recent
sun sensor data indicates that the antenna is "more open", and this is either
due to one of the three stuck ribs popping loose,
or increased tension on the antenna is causing it to bend out more.  Several
more hammering sessions are scheduled this month to keep applying more force
on the ballscrew to free the stuck ribs.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Choose a job you love, and
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | you'll never have to work
|_____|/  |_|/       |_____|/                     | a day in your life.

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

Date: Mon, 4 Jan 1993 17:06:57 GMT
From: "Edward V. Wright" <[e-mail]>
Subject: How many flights are Orbiters designed for?
Newsgroups: sci.space

In <[e-mail]> [e-mail] (Allen W. Sherzer) writes:

>DC could be available long before then *IF* we can get DoD to fund the
>proof of concept vehicle.

If we can get *someone* to fund the proof-of-concept vehicle.  DoD
may still have the deepest pockets around, but I certainly hope
McDAC is looking at other sources also.  Perhaps the Japanese
would be interested in a joint partnership.  It's too bad the
Delta Clipper wasn't started several years ago when McDonnell Douglas
was healthy enough to finance such a project itself.

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

Date: 4 Jan 93 18:14:13 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: How many flights are Orbiters designed for?
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Edward V. Wright) writes:

>>DC could be available long before then *IF* we can get DoD to fund the
>>proof of concept vehicle.

>If we can get *someone* to fund the proof-of-concept vehicle.  DoD
>may still have the deepest pockets around, but I certainly hope
>McDAC is looking at other sources also.

There will be no private financing of a SSTO proof of concept. The current
and projected market is simply too small and not profitable enough to
warrent private capital.

   Allen

--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "A great man is one who does nothing but leaves        |
|  [e-mail]     |  nothing undone"                                       |
+----------------------110 DAYS TO FIRST FLIGHT OF DCX----------------------+

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

Date: 4 Jan 93 17:17:00 GMT
From: "Edward V. Wright" <[e-mail]>
Subject: Let's be more specific (was: Stupid Shut Cost arguement
Newsgroups: sci.space

In <[e-mail]> [e-mail] (Brian Stuart Thorn) writes:

>    As Gary and I pointed out, Pegasus really started slipping after
>    maiden flight... about eighteen months between flights 2 and 3, to
>    be precise. That DC-X has slipped little prior to maiden flight is
>    a good sign, but hardly justifies such smugness.

Well, after the first Pegasus flight, they had to build another one.
Not because it failed, but because it worked.  Unless something
catastrophic happens on the first test flight, you won't have to
build another DC-X before the second one.



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

Date: 4 Jan 93 17:05:26 GMT
From: Don Thompson <[e-mail]>
Subject: Nasa flight sim code
Newsgroups: sci.space

    Would anyone happen to know where a body could get information
on old flight simulation code written by NASA or any of the military
branches? I am interested in obtaining any code that might be declassified
and publicly availible. In addition, any data related to the flight models
of old or new aircraft would be nice.

                    Thanks


--
________________________________________________________________________________
Don "Syco" Thompson                 |   I may be opinionated, but at least
Comshare Inc. [e-mail]  |   my opinions are my own.
--------------------------------------------------------------------------------
    "There's no kill like a guns kill".  Lt Commander Joe "Hoser" Satrapa, USN
--------------------------------------------------------------------------------

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

Date: 4 Jan 93 17:20:30 GMT
From: "Edward V. Wright" <[e-mail]>
Subject: Shuttle a research tool (was: Re: Let's be more specific)
Newsgroups: sci.space

In <[e-mail]> [e-mail] (Francois Yergeau) writes:

>If I build a custom laser in my lab, and then operate it purely
>as a tool to support my research program, I think I am still doing
>research.  Likewise, when NASA is using the shuttle to fly Spacelab,
>TSS, Hubble, etc, it's doing research.

If you pay Air France to fly your laser to the research site,
does that mean the Airbus is a research vehicle?

>Even a TDRS launch is part of the research effort, since the
>constellation is used to support various birds doing research
>missions.

If you call someone in New York to discuss your research, the
call goes via Intelsat or undersea cable.  Does that make the
Intelsat or the cable a research venture?

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

Date: Mon, 4 Jan 1993 16:51:58 GMT
From: "Edward V. Wright" <[e-mail]>
Subject: SSTO vs 2 stage
Newsgroups: sci.space

In <[e-mail]> Graydon <[e-mail]> writes:

>What I understood Bruce to be proposing/discussing was the idea of
>building a bottom stage for a DC-1 for those occaisons when a 'heavy'
>payload needed launch.  (Heavy - either something that grosses out
>long before it bulks out the cargo bay, or something that is going
>higher than LEO on one launch (for whatever reason)).

I understood that too.  Perhaps you did not understand what I meant
when I said, if there are enough heavy cargoes to justify a new
vehicle, it would be more cost-effective to build a larger SSTO
than a two-stage kludge?

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

Date: 4 Jan 93 18:02:56 GMT
From: Graydon <[e-mail]>
Subject: SSTO vs 2 stage
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Edward V.
Wright) says:
>
>In <[e-mail]> Graydon <[e-mail]>
>writes:
>
>>What I understood Bruce to be proposing/discussing was the idea of
>>building a bottom stage for a DC-1 for those occaisons when a 'heavy'
>>payload needed launch.  (Heavy - either something that grosses out
>>long before it bulks out the cargo bay, or something that is going
>>higher than LEO on one launch (for whatever reason)).
>
>I understood that too.  Perhaps you did not understand what I meant
>when I said, if there are enough heavy cargoes to justify a new
>vehicle, it would be more cost-effective to build a larger SSTO
>than a two-stage kludge?

Rather depends on how many heavy cargoes there are, doesn't it?

As I understand it, the point to an SSTO is to make expendables
non-cost effective.  So there *won't* be another vehicle fairly
soon after DC-1's get flying in numbers if they work as advertised.

If there's one or two heavy cargoes a year, Bruce's quick and simple
second stage might make a great deal more sense than scaling up
an SSTO design by a factor of five, which I would expect to be quite
difficult, since it's a complete re-design and probably needs new
engines.

A company with three or four bottom stages could happily specialize
in lifting other people's DC-1s with heavy cargos (land your DC-1
next to their stacking facility after its last trip up) and make
decent money at it if there were enough cargoes ('enough' quantified
after someone does a real design study for the thing and provides
some numbers for things that need to go up in one piece and weigh
between 10 and 50 tons.)

Why would you expect the design effort for a factor five scale up
to be less expensive?

Graydon

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

Date: 4 Jan 93 18:09:47 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: Stupid Shut Cost arguements (was Re: Terminal Velocity
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Brad Whitehurst) writes:

>    If men are part of the payload, the Shuttle is (currently) the
>only way to fly!

I think if you consult the Russians they can show you the error in
this statement.

BTW, the team evaluating Soyuz has finished its work. They concluded that
there is no reason Soyuz couldn't be used as ACRV. It should also be
possible to use Soyuz on an Atlas or Titan for US manned space.

    Allen

--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "A great man is one who does nothing but leaves        |
|  [e-mail]     |  nothing undone"                                       |
+----------------------110 DAYS TO FIRST FLIGHT OF DCX----------------------+

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Date: 4 Jan 93 15:23:49 GMT
From: Gary Coffman <ke4zv!gary>
Subject: Terminal Velocity of DCX? (was Re: Shuttle ...)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Edward V. Wright) writes:
>In <[e-mail]> [e-mail] (Gary Coffman) writes:
>
>>Nonsense. The Russians have built no space stations and are having
>>trouble raising the funds to operate the one they inherited from
>>the Soviet Union. Comparing what was done by a command economy using
>>what amounts to slave labor to what's done in an open society where
>>people expect to get paid fairly for their work is meaningless accounting.
>
>Well, Gary, some of us have the theory that free societies are
>more efficient than "command economies."

Then our launchers should be cheaper than theirs. And what I'm saying
above is that indeed I think they are when all their hidden costs are
properly assigned.

Gary

--
Gary Coffman KE4ZV          |    You make it,     | gatech!wa4mei!ke4zv!gary
Destructive Testing Systems |    we break it.     | uunet!rsiatl!ke4zv!gary
534 Shannon Way             |    Guaranteed!      | emory!kd4nc!ke4zv!gary
Lawrenceville, GA 30244     |                     | emory!ke4zv![e-mail]

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End of Space Digest Volume 15 : Issue 631
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