Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V15_4/V15NO419.TXT

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Date: Fri, 13 Nov 92 05:08:35
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #419
To: Space Digest Readers
Precedence: bulk


Space Digest                Fri, 13 Nov 92       Volume 15 : Issue 419

Today's Topics:
                             Apollo fire
            Automated space station construction (3 msgs)
                                Dante
                        Early life discussions
                              Hard suits
                             Ice hardness
                Lunar "colony" reality check (2 msgs)
                           Man in the loop
                       Names for Venus Features
                          reality check (2)
                    Space suit research? (2 msgs)
                        Space suit research???
             Study says: Space research spinoffs marginal
                           The Big Picture
       The story on Oxygen Was Re: Lunar "colony" reality check
              What kind of computers are in the shuttle?
                Where are Pioneer and Voyager Headed?

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

Date: 12 Nov 92 21:19:15 GMT
From: Curtis Roelle <roelle@uars_mag.jhuapl.edu>
Subject: Apollo fire
Newsgroups: sci.space

[e-mail] (Henry Spencer) writes:

>............ Mercury
>used normal air for ground pressurization, although I believe the astronaut
>breathed pure oxygen at all times.  However, it turned out that there were
>risks in this approach:  a technician was killed in an accident which would
>not have happened with pure oxygen.  (I don't have details, but I would
>guess a pressure-chamber test went awry and he ended up breathing air at
>low pressure.)

Around 7-8 years ago several technicians died at space shuttle pad 39A
or B when they entered a chamber of pure Nitrogen (during a purge?).
Does anyone have more information about that?  I believe they were
contractors with Rockwell.

A broader question is: In the history of the U.S. manned space program,
what other fatal accidents have ground crews members been involved
in at the Cape?

Curt Roelle
[e-mail]

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

Date: Thu, 12 Nov 1992 22:39:23 GMT
From: Philip Graves <[e-mail]>
Subject: Automated space station construction
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Kieran A. Carroll) writes:
>In article <[e-mail]> [e-mail] (Frank Crary) writes:
>>Is anyone looking into robots with very limited autonomy? That is,
>>under direction from a human, but able to execute instructions on
>>their own for periods of, say, ten seconds?
>>
>>                                         Frank Crary
>>                                         CU Boulder
>
>Yes. The Canadian Space Agency (who are developing the Mobile
>Servicing System for SSF) are spending about CDN$50M per year
>on research into automating various aspects of MSS, through their
>STEAR (Strategic TEchnologies for Automation and Robotics)
>program. The work is being done by various Canadian companies,

A system has been developed at NASA-JSC which demonstrates earth
based control of SSF robotics maintenance tasks. It consists of a
workstation where a human can control a manipulator system which
is in a room across the hall. Tests were performed to determine
the communications delays by routing all signals
between the workstation and manipulator through a series of satelites
and ground stations which are used to test the shuttle communications
path. Since this communications route is not available for robot
experiments very often, the delay was measured and can be "simulated".
It is hoped that this system can be developed into a ground
control station for SSF maintenance.

The Shuttle Remote Manipulator System has a little used (if ever used)
mode called Automatic Control Function, which is capable of tracking
a preprogrammed trajectory. That's about as autonomous as the
system gets, mainly because it is lacking the sensory systems
required for anything more sophisticated.


--
--------------------------------------------------------------
Philip Lee Graves, [e-mail]
--------------------------------------------------------------

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

Date: Thu, 12 Nov 1992 23:36:55 GMT
From: david michelson <[e-mail]>
Subject: Automated space station construction
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Allen W. Sherzer) writes:
>In article <[e-mail]> [e-mail] (Gary Coffman) writes:
>
>>Military COBOL and Intel processors, FRED IS DOOMED. :-) :-)
>
>Oh I don't know about that. After all, the Terminator used COBOL and
>8080 assembly language and it worked pretty good.
>
>  Allen
>

It looked like Apple ][ (6502) assembly language to me!

--
Dave Michelson
[e-mail]

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

Date: 12 Nov 92 15:26:33 GMT
From: Bob Pendleton <[e-mail]>
Subject: Automated space station construction
Newsgroups: sci.space

From article <[e-mail]>, by [e-mail] (Gary Coffman):
> In article <[e-mail]> [e-mail] (Charles Frank Radley) writes:
>>Space Station Freedom is Apollo type technology ?
>>Really ?
>>
>>Using ADA and 386 / 586 processors and Nickel Hydrogen batteries,
>
> Military COBOL and Intel processors, FRED IS DOOMED. :-) :-)

Get your history straight. COBOL was a US Navy project. The Air Force
also had it's own programming language. ADA is the result of
inter-service rivalry :-)

            Bob P.

--
Bob Pendleton             | As an engineer I hate to hear:
[e-mail]              |   1) You've earned an "I told you so."
Speaking only for myself. |   2) Our customers don't do that.
                   <<< Odin, after the well of Mimir. >>>

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

Date: Thu, 12 Nov 92 22:53:33 EST
From: John Roberts <[e-mail]>
Subject: Dante

-From: [e-mail] (Lawrence Curcio)
-Subject: Re: Mars Simulation in Antarctica
-Date: 12 Nov 92 04:24:24 GMT
-Organization: Doctoral student, Urban and Public Affairs, Carnegie Mellon, Pittsburgh, PA

-Is this rover the same robot we at CMU call, AMBLER? Big red sucker?
-Legs arranged like eggbeaters?

..........

-From: [e-mail] (Samuel John Kass)
-Date: 12 Nov 92 03:45:44 GMT
-Organization: Sophomore, Math/Computer Science, Carnegie Mellon, Pittsburgh, PA

-    Basically, Dante looks like a big, purple bug.  It's transport
-counterpart, "Virgil" (which was dropped from the Antarctica mission due
-to manpower and time constraints) looked like a high-tech purple dune
-buggy with lots of extra wheels.

Hm, I wonder how they came up with that name. :-)  :-)
It's very, *very* purple - I saw it on display at the rover exposition in
Washington, D.C. a few months ago. (Is the color functional?)

Here are some notes I took at the exposition:

............

  - Dante -- the Erebus Explorer
    size: 3.0 x 1.9 x 3.5 meters
    mass: 400 kg
    speed: 2 cm/s
    comments: Another (6-legged?) walker, hard to describe. It appears to
      be made of beautiful purple anodized aluminum. It's intended to explore
      the active volcano Mount Erebus in Antarctica in 1992. Another robot,
      Virgil, also called the transporter, is to ascend to the rim of the
      crater, where it will lower Dante, also called the rappeller, to observe
      the lava lake, measure temperatures, take samples, etc. Not scheduled
      for a demo. Cameras return anaglyph stereo display.

............

-    If our newspaper reports anything new and exciting, I'll be sure to
-post again.
-    --Sam

Please do so.

John Roberts
[e-mail]

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

Date: Fri, 13 Nov 92 00:45:27 GMT
From: [e-mail]
Subject: Early life discussions

> Now, tell us all about the experiments that made pure
> 5'-Phosphorimidazolide of Adenosine with a spark from CO2, nitrogen
> and water.
>

> It's a fine tradition in origin-of-life research to assume away
> your starting materials.  Rather a waste of time, IMO.
>


If I run across such a reference, I will post it for the use of those
arguing on this thread. I am not. Calm down for chrissake.

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

Date: Thu, 12 Nov 92 22:41:36 EST
From: John Roberts <[e-mail]>
Subject: Hard suits

-From: [e-mail] (Gary Coffman)
-Subject: Re: Space suit research???
-Date: 12 Nov 92 04:48:26 GMT
-Organization: Gannett Technologies Group

-In article <[e-mail]> [e-mail] (STANCZYK MICHAEL B) writes:
->With all the talk about US space suits being at 5 psi and pure O2 I was
->wondering what the current state of research is in space suits using
->1 atm and normal air?

-Imagine a starfish. Constant volume joints aren't constant volume. At
-1 atm, you can't move unless you're Arnold S. The suit fabric becomes
-so stiff when inflated to 14 PSI that you can't get any feeling through
-it, gloves don't work. 1 atm suit designs are hard suits with remote
-manipulators, one man space ships, not suits at all.

The prototype hard suit I've seen pictures of isn't made of fabric (at
least on the outside), and it doesn't use remote manipulators. It appears
to be made of rigid white plastic, though I suppose it could be metal.
The joints are made of pieces that slide over one another - the general
appearance is that of a medieval suit of armor. I *think* the finger joints
are similarly constructed, but I don't remember the details.

One concern that's been expressed over the eventual introduction of this
suit is pneufrancaisophobia - the fear of looking like the Michelin Man. :-)

John Roberts
[e-mail]

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

Date: 12 Nov 92 14:34:49 GMT
From: Charles Frank Radley <[e-mail]>
Subject: Ice hardness
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Donald Lindsay) writes:



>Being hard doesn't mean that bulk material is without flaws. It
>wouldn't be surprising if the explosion caused major fracturing.
>Precisely how much, would be unpredictable.

>Don        D.C.Lindsay     Carnegie Mellon Computer Science
-
Indeeed.  Hardness and strength do not prevent a material from containing
numerous flaws, large and small.
  Flaws can propogte, regardless of the strength or hardness of the material.

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

Date: Fri, 13 Nov 1992 00:10:20 GMT
From: Jr Childers <[e-mail]>
Subject: Lunar "colony" reality check
Newsgroups: sci.space,alt.sci.planetary

In article <[e-mail]> [e-mail] (Craig L. Cole) writes:
>In article <[e-mail]>, [e-mail] writes...

>>In article <[e-mail]>, [e-mail] (John D. Boggs) writes:
>>=From article <[e-mail]>, by jenkins@fritz (Steve Jenkins):
>>=>
>>=> Oxygen, like many gases, has narcotic effects at very high pressures,
>>=> such as in deep-sea diving.  It can cause blindness in newborns
>>=>
>>=
>>=Yes to blindness in newborns, but it is the *nitrogen* that has the narcotic
>>=effect in deep sea diving -- hence the use of helium for the really really
>>=deep dives.
>>
>>If oxygen at high pressures DIDN'T cause the bad effects, why bother mixing it
>>with helium?  Yes, nitrogen has narcotic effects at high pressure, but so does
>>oxygen.

I am a diver but, I've never used helium underwater.  Well has anyone here
been up over 100km? :-)  What you are refering to is mixed gas diving,
which is mostly (only) used by professionals.

In mixed gas systems the O2 pressure is keep at 0.2atm to maybe 0.5atm.
The rest of the pressure is madeup  with helium and some times N2 at 0.8atm.
Note that the O2 level is above normal for a very good reason.  When
assending the gases expand and their pressures drop.  Going from 100ft (30m)
to the surface is a drop of 4atm and professionals don't like blackouts. :-)
>
>I'm no expert at deep sea diving or anything, but don't they use the helium
>to increase to total atmospheric pressure in their submerisibles? So that
>the pressure inside and outside the craft are more equal?

Submerisibles are keep at 1 atm to avoid any need for decompression or
mixed gases, unless of coures a  diver is going to leave the sub at depth.

>This is the opposite of space --  these guys are trying keep there craft
>from imploding due to pressure. Increasing the pressure inside the craft
>reduces the loads on the craft's strucutre.

Adding pressure increases the sub's operating depth by only
10m/atm (33ft/atm) and 10m is not a real improvement when
when the sub is built to operate 1km to 10km down.



Is anyone else amazed at how little most people know about the air they
need to survive.


John Childers                 | We're sorry,
University of North Carolina at Charlotte| all quotes are on
Electrical Engineering Department     | backorder.
Charlotte NC 28223             |
Internet? Try [e-mail]     |
---------------------------------------------------------------------------
Disclaimer?  Does anyone on usenet ever offically speak for their computer?

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

Date: Fri, 13 Nov 1992 00:21:31 GMT
From: Jr Childers <[e-mail]>
Subject: Lunar "colony" reality check
Newsgroups: sci.space,alt.sci.planetary

In article <[e-mail]> [e-mail] (Steve Linton) writes:
>In article <[e-mail]>, [e-mail] (John D. Boggs) writes:
>|> From article <[e-mail]>, by jenkins@fritz (Steve Jenkins):
>|> >
>|> > Oxygen, like many gases, has narcotic effects at very high pressures,
>|> > such as in deep-sea diving.  It can cause blindness in newborns
>|> >
>|>
>|> Yes to blindness in newborns, but it is the *nitrogen* that has the narcotic
>|> effect in deep sea diving -- hence the use of helium for the really really
>|> deep dives.
>
>Oxygen causes drunkenness-like symptoms above around 2atm. Any inert gas (except

According to my scuba text books O2 causes death at a partial pressure of
2atm not narcosis!  Nitrogen begins causing narcosis at a pressures of about
4-5atm.

>helium, which I'll come back to) causes narcosis (anaesthesia) at sufficient
>partial pressure. Roughly, the larger the molecule, the lower the pressure
>needed. For nitrogen it's about 10atm, for ether or chloroform, less than 1.


John Childers                 | We're sorry,
University of North Carolina at Charlotte| all quotes are on
Electrical Engineering Department     | backorder.
Charlotte NC 28223             |
Internet? Try [e-mail]     |
---------------------------------------------------------------------------
Disclaimer?  Does anyone on usenet ever offically speak for their computer?

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

Date: Thu, 12 Nov 92 23:06:21 EST
From: John Roberts <[e-mail]>
Subject: Man in the loop

-From: [e-mail] (IGOR)
-Subject: Re: Man in the loop
-Date: 12 Nov 92 00:00:00 GMT
-Organization: Texas A&M University, Academic Computing Services

-Actually one is giving control to the machine so that the human can
-THINK about what is going wrong. Most of the research in specific accidents
-such as Loss Of Coolant Accident (LOCA) are studied in a way to allow the
-operator a safe margin of time to see what he can do to stop the whole process.

->It's true that the human is always given the last word, but then if you
->look at nuclear power plant accidents, they seem to occur most when the
->human intervenes.

-While it might be true for the Chernobyl disaster, for Three Miles
-Island accident even the machine
-could not do anything since they were not designed to handle this huge hydrogen
-bubble.

-Igor
-Nuclear Engineering Department
-Texas A&M University

I thought one of the the major contributors to the TMI incident was that
when things started to go wrong, the human operators panicked and *shut off*
the automatic safety systems. I had the impression that the automatic
systems might have been able to keep things relatively under control if
they hadn't been overridden.

The Chernobyl operators caused the explosion by performing a test which was
supposedly to show how safe the reactor was. In order to create a hazard
condition with which to demonstrate the recovery, they deliberately
operated the reactor far outside the specifications permitted by the safety
rules. The reactor power suddenly increased manyfold, and there was no time
for the operators to react.

This is not to say that reactors can't be designed to be much safer than
the current US models - I believe there's an ongoing effort in this direction.

John Roberts
[e-mail]

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

Date: 13 Nov 92 01:45:52 GMT
From: MURTY Hema Sandhyarani <[e-mail]>
Subject: Names for Venus Features
Newsgroups: sci.space

    Does anyone have information concerning a recent request
    for names for features on Venus?  Is the search still
    active and if so, where do we send the names to?  I recall
    that the names had to meet certain criteria.

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

Date: Thu, 12 Nov 92 22:24:01 EST
From: John Roberts <[e-mail]>
Subject: reality check (2)

-From: [e-mail] (Doug Mohney)
-Subject: Re: Reality check (2)
-Date: 12 Nov 92 15:51:03 GMT
-Organization: Computer Aided Design Lab, U. of Maryland College Park

-In article <[e-mail]>, [e-mail] (John Roberts) writes:
-[in reference to doing work on the moon...]
->I think a lot of the initial work could be done with robots, more cheaply than
->sending humans there right away. (Once we know more, and hopefully have more
->appropriate launchers, we can send humans.)

-You'll need some humans hanging around, just to apply duct tape.

Eventually, sure. But I was referring mainly to the very beginning of the
process - things that could potentially be done starting just a few years
from now. You don't need humans around just to figure out how to pound sand.
For example - teleoperated rovers have already been sent to the moon (by the
Russians) - we could do more of that, to locate good sites. "Earth moving"
and "factory" functions would be more of a challenge, but we could start
small - something on the order of the Viking landers. I suspect with
concentration on the "smaller, faster, cheaper" approach, we could get in
several good lunar surface missions for under a billion dollars - while it
would cost many billions and require a new (or restored) launcher to send
even one person to the moon. While the robotic missions are underway, new
launchers will (hopefully) be coming along, and launch costs will (hopefully)
be dropping, so by the time we can afford to send humans to the moon, we'll
have a much clearer idea of what they should be doing.

Anyway, I don't think we ever established that duct (grey) tape remains
sticky after long exposure to vacuum. Experience from Skylab and the Shuttle
shows that it will work for short periods.

John Roberts
[e-mail]

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

Date: 12 Nov 92 23:39:07 GMT
From: Rich Kolker <[e-mail]>
Subject: Space suit research?
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (John Roberts) writes:
>
>-From: [e-mail] (Henry Spencer)
>-Subject: Re: Space suit research???
>-Date: 11 Nov 92 21:27:59 GMT
>
>-Advanced spacesuit research is basically stalled for lack of funding.
>-A high-pressure suit (probably 8psi or so rather than full normal
>-pressure -- most people can take a certain amount of pressure change
>-without much risk of the bends) was planned for the space station but
>-scuttled by funding cuts.  It would still be useful, because prebreathing
>-greatly increases the time needed for a spacewalk.
>
>In the NASA Select coverage of a Shuttle mission (this year, I think) in which
>EVAs were used, I believe the commentator remarked that with something other
>than the usual pre-EVA cabin depressurization, only about half an hour of
>EVA pre-breathe was required. I considered that to be an astounding
>statement, but I never heard any followup. (I'm pretty sure that the mission
>was STS-49, and the cabin pressure was 10.2 psi.)
>
>Has anyone else heard anything about this?
>

That's correct.  By lowering the cabin pressure to 10.2 psi and keeping it
there for a number of hours, the prebreathe is decreased.  It's now
standard procedure for shuttle EVAs when possible.

++rich

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

Date: Thu, 12 Nov 92 22:30:52 EST
From: John Roberts <[e-mail]>
Subject: Space suit research?

-From: [e-mail] (Michael K. Heney)
-Subject: Re: Space suit research?
-Date: 12 Nov 92 14:00:12 GMT
-Organization: Express Access Online Communications, Greenbelt, MD USA

-In article <[e-mail]> [e-mail] (John Roberts) writes:
->
->In the NASA Select coverage of a Shuttle mission (this year, I think) in which
->EVAs were used, I believe the commentator remarked that with something other
->than the usual pre-EVA cabin depressurization, only about half an hour of
->EVA pre-breathe was required. I considered that to be an astounding
->statement, but I never heard any followup. (I'm pretty sure that the mission
->was STS-49, and the cabin pressure was 10.2 psi.)

-I remember that, too - I recall that the Shuttle cabin pressure was reduced
-to 8.4 (?) psi, which gretly reduced the pre-breathe times.  Given the
-number of EVA's they had to do on that flight (Intelsat rescue), this
-was a Very Good Thing.

Thanks for the confirmation. 8.4 psi sounds plausible - 10.2 seemed a little
high, since they always depressurize somewhat in preparation for an EVA.

Anyone recall whether there was an unusually high rate of equipment
failure for that flight that might be associated with the lower pressure?
(Other than the fax machine jamming as usual, of course. :-) I remember
that one or more of the cargo bay lights burned out, but that wouldn't
be pressure-related.

John Roberts
[e-mail]

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

Date: 13 Nov 92 03:36:53 GMT
From: "Michael V. Kent" <[e-mail]>
Subject: Space suit research???
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Frank Crary) writes:
>
>The current (unfunded) goal is for a 8.5 psi "no pre-breath"
>pure-oxygen suit. One of the proposed designs (the Ames Hard Suit)
>doesn't suffer at high pressures, so in theory it could go all
>the way up to one atmosphere (although this isn't currently
>planned for...)

What type of line item would the Ames Hard Suit (or the competing design)
need to move forward at a reasonable pace?

Mike

--
Michael Kent                                   [e-mail]
McDonnell Douglas                              Rensselaer Polytechnic Institute

Tute Screwed Aero Class of '92                              Apple II Forever !!

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

Date: Thu, 12 Nov 1992 18:20:25 -0500
From: Lawrence Curcio <[e-mail]>
Subject: Study says: Space research spinoffs marginal
Newsgroups: sci.econ,sci.space

Source-Info:  Sender is really [e-mail]

I would think that the spinoffs od space research in the realm of
materials science would be neither marginal nor random.

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

Date: 12 Nov 92 14:04:52 GMT
From: "T. Joseph Lazio, Cornell University" <[e-mail]>
Subject: The Big Picture
Newsgroups: sci.space

In article <[e-mail]>,
[e-mail] (Philip Young) writes:
> Given our propensity to fling hardware into the heavens, and our desire
> to get a good handle on what's very old and far away, has anybody done
> any serious investigation of the possibility of tacking astronomical eyes
> on craft headed for interstellar space which would be suitable for
> verrrrrrrrrrrry long baseline interferometry?  We're not just talking
> Earth orbit here. Seems to me we have the clocks, the computers, the
> comms.  What would be the shortest frequency we could realistically
> deal with?  Could costs be contained with a standardized, shrink-wrapped
> observatory package?  What might we discover with a (radio?) telescope
> whose effective diameter increases 10E+4 km/sec or more for the forseeable
> future?

 I haven't looked into some of the technical details you mention, so
 I'll comment on the scientific and historic.

 Very Long Baseline Interferometry (VLBI) with space based telescopes
 has been done with a TDRSS satellite.  Both the former Soviet Union
 and Japan had/have projects, RadioAstron and VSOP, respectively, to
 do VLBI from satellites.  Also there is a project in Italy and the
 U.S. (still on the drawing board) called SETIsail which would use a
 solar sail as a radio telescope.

 There are two major scientific hurdles.  First, there must be something
 to see.  Interferometers act as filters:  Objects smaller than the
 resolving power of the instrument are broadened and objects more
 extended than the angular size to which the smallest baseline is
 sensitive will not be seen.  This last property is peculiar to
 interferometers.  What it means is that if you have two antennas,
 one on the ground and one a distance 1 A.U. away, in order for the
 interferometer to see anything, there must be astronomical objects
 whose angular size is about
                            wavelength/baseline

 where baseline = 1 A.U.  If there are no astronomical objects with
 angular sizes less than or about this size, the interferometer will
 detect nothing.

 Second, one must take into account interstellar scintillation (ISS).
 ISS is like astronomical seeing at visible wavelengths, it broadens
 the angular size of objects.  ISS could be (probably is) the
 limiting factor in determining the angular size of objects.  ISS
 is neat though, in that there are ways of exploiting it to mock up
 large baselines (~ 1 A.U.) and there are hints that on these size
 of baselines one could resolve pulsar magnetospheres.

 Thus, we have problems with VVLBI (Very, Very Long Baseline Interferometry).
 ISS results in a lower limit to the angular size of radio sources,
 interferometers cannot detect anything larger than the minimum
 fringe spacing, so there may not be anything to see.  Even without
 ISS, there are hints that pulsar magnetospheres (probably the most
 compact astronomical source known) could be resolved with 1 A.U.
 baselines.  Hence, baselines substantially larger than this are probably
 not worthwhile.

 There is one caveat; one hypothetical radio source would be more
 compact than pulsar magnetospheres: radio telescopes on another
 planet.  Hence, with a VVLBI, one could use the filtering power
 of the interferometer to screen out all known astronomical sources
 and anything left over would be, by definition, an artifical source.

--
 T. Joseph Lazio                | Why relativity? and Why
 514 Space Sciences             | turbulence?  I really believe
 Ithaca, NY  14853-6801         | [God] will have an answer for the
 [phone]                 | first [question].
 [e-mail]  |   -- W. Heisenberg, on his death bed
ICBM:                           |
 42 deg. 20' 08" N              |              STOP RAPE
 76 deg. 28' 48" W              |

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

Date: Fri, 13 Nov 1992 00:36:07 GMT
From: Jr Childers <[e-mail]>
Subject: The story on Oxygen Was Re: Lunar "colony" reality check
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (David Knapp) writes:
>In article <[e-mail]> [e-mail] (Steve Linton) writes:

[ A very good correction to the O2 noise cut due to common sense. ]

>I'm not sure if it[helium] dissolves less into blood than N2 but I know that
>decompression is still an issue using heliox mixes.
>
>--
>David Knapp                                   University of Colorado, Boulder
>Perpetual Student                                 [e-mail]
>Looks like hate *is* a family value after all and Colorado families are for it.
>

Helium being a much smaller molecule than N2 will diffuse into and out of
blood, bone nerves, and anything else much more quickly than N2.  This makes
decompression more of a problem for helium.

And thankyou for some clear and accurate information.

John Childers                 | We're sorry,
University of North Carolina at Charlotte| all quotes are on
Electrical Engineering Department     | backorder.
Charlotte NC 28223             |
Internet? Try [e-mail]     |
---------------------------------------------------------------------------
Disclaimer?  Does anyone on usenet ever offically speak for their computer?

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

Date: 13 Nov 92 03:54:26 GMT
From: "Michael V. Kent" <[e-mail]>
Subject: What kind of computers are in the shuttle?
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Rich Kolker) writes:

>Now, if we can just get the money for the glass cockpit...

Rockwell recently won a multi-million dollar contract to upgrade the Shuttle's
avionics.  This contract is the one, I believe, that is known as glass cockpit.

Mike

--
Michael Kent                                   [e-mail]
McDonnell Douglas                              Rensselaer Polytechnic Institute

Tute Screwed Aero Class of '92                              Apple II Forever !!

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

Date: 12 Nov 92 22:01:54 GMT
From: Gerald Cecil <[e-mail]>
Subject: Where are Pioneer and Voyager Headed?
Newsgroups: sci.space

In article [e-mail], [e-mail] (Henry Spencer) writes:
>In article <[e-mail]> [e-mail] (Nick Haines) writes:
>>... AC +79 3888 must be sqrt (1.5^2 + 1.65^2) = 2.23 ly from
>>the sun, according to the Pioneer figures, and sqrt (2.2^2 + 1.64^2) =
>>2.74 ly from the sun according the the Voyager figures. Not only are
>>these numbers very different from each other, they're also much less
>>than the correct distance to AC +79 3888.
>>
>>Doing the same calculation for Ross 248 gets us a distance of 3.5 ly
>>(correct figure is 10.3), and for Sirius 26.8 ly (correct figure is
>>8.7 ly).
>
>Bear in mind that the stars are moving, in many cases at rather higher
>velocities than the spacecraft.
>--
>MS-DOS is the OS/360 of the 1980s.      | Henry Spencer @ U of Toronto Zoology
>              -Hal W. Hardenbergh (1985)|  [e-mail]  utzoo!henry

Yes.  Typical velocity dispersions for K- and M-dwarfs in the solar neighbourhood
are 20 km/s or so, which translates into >0.6 ly drift per 10,000 yrs.
---
Gerald Cecil [e-mail]  919-962-7169
Physics & Astronomy, U of North Carolina, Chapel Hill, NC 27599-3255 USA

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End of Space Digest Volume 15 : Issue 419
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