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Date: Sat, 21 Nov 92 05:03:01
From: Space Digest maintainer <digests@isu.isunet.edu>
Reply-To: Space-request@isu.isunet.edu
Subject: Space Digest V15 #444
To: Space Digest Readers
Precedence: bulk
Space Digest Sat, 21 Nov 92 Volume 15 : Issue 444
Today's Topics:
ACTS Conference proceedings
Clinton's address (was Re: Feynmann's legacy)
COSTAR
Magellan Update - 11/20/92
Mars Observer Update - 11/20/92
ROTATION OF THE MOON (2 msgs)
shuttle computers
Shuttle replacement (2 msgs)
Solar Sailing
space news from Oct 23 Science (not AW&ST)
Space suit research? (4 msgs)
SSTO viability
Welcome to the Space Digest!! Please send your messages to
"space@isu.isunet.edu", and (un)subscription requests of the form
"Subscribe Space <your name>" to one of these addresses: listserv@uga
(BITNET), rice::boyle (SPAN/NSInet), utadnx::utspan::rice::boyle
(THENET), or space-REQUEST@isu.isunet.edu (Internet).
----------------------------------------------------------------------
Date: Fri, 20 Nov 1992 18:46:40 GMT
From: Gary Hughes - VMS Development <hughes@gary.enet.dec.com>
Subject: ACTS Conference proceedings
Newsgroups: sci.space
Do any of the NASA folks on the net know if there are proceedings and/or
'handouts' from the ACTS conference (Nov 18-19 I think) available and, if so,
who to contact?
tia
gary
------------------------------
Date: 21 Nov 1992 00:27:44 GMT
From: Jeffrey Alan Foust <jafoust@cco.caltech.edu>
Subject: Clinton's address (was Re: Feynmann's legacy)
Newsgroups: sci.space
In article <1992Nov19.112836.1@max.u.washington.edu> games@max.u.washington.edu writes:
>In article <1ee80gINNap@gap.caltech.edu>, jafoust@cco.caltech.edu (Jeffrey Alan Foust) writes:
>>The Clinton/Gore campaign did have an account on CompuServe (I don't remember
>>the account number). I had heard some talk after the election that they
>>would keep the account, but I haven't heard a final decision yet.
>>
>> --
>Well, I tried to mail to that account, and got the message returned saying
>that the mailbox was full. It seems that even though the store is there,
>noone is minding it.
I recall now someone on one of the alt.politics.* groups mentioning that the
Clinton campaign, er, transition team would not be reading the mail sent to it
very often, if at all, for the first few weeks after the election, until they
decided whether or not to keep the account. Of course, I ran into the problem
of mail bouncing during the summer, when I had to resend a mail message to the
campaign several times before it didn't bounce back due to a full mailbox!
--
Jeff Foust Senior, Geophysics/Planetary Science, Caltech
jafoust@cco.caltech.edu jeff@scn1.jpl.nasa.gov
Tom Seaver: "Hey, Yogi, what time is it?"
Yogi Berra: "You mean now?"
------------------------------
Date: Fri, 20 Nov 92 23:23:37 EST
From: John Roberts <roberts@cmr.ncsl.nist.gov>
Subject: COSTAR
-From: roelle@uars_mag.jhuapl.edu (Curtis Roelle)
-Subject: Re: COSTAR
-Date: 19 Nov 92 21:58:23 GMT
-Organization: Johns Hopkins University
-roberts@cmr.ncsl.nist.gov (John Roberts) writes:
->Somewhat more plausible scenario - the mirrors only partially deploy,
->blocking the original light paths, but not implementing the new light paths,
->and efforts to retract them fail. (I presume they'll try to deploy while
->HST is still attached to the Shuttle - if all else fails, a couple of burly
->astronauts can try to yank the whole assembly out of HST.)
-What if they're not burly enough? Is there a contingency plan to retrieve
-HST from orbit if all fails, or, would it be jettisoned, even if that meant
-leaving it in a non-usable configuration?
I believe it would take a special cradle to carry HST, which may well take
up the entire cargo bay. Since several bulky new parts have to be brought
along, there probably wouldn't be room. Even if COSTAR somehow screwed up
all the axial instruments, HST wouldn't be useless - WF/PC II and the
fine guidance sensors wouldn't be affected.
I attended the HST lecture on Thursday (I'll try to post some notes soon),
and saw photographs and detailed diagrams of COSTAR. The mirror assembly
is much smaller than I had pictured, so if it did get stuck, I imagine
it wouldn't be too hard to yank out. If that didn't work, it might be
possible for the astronauts to remove one or more of the other three axial
instruments to provide a direct access to the assembly. In any event, the
COSTAR extensions are designed to be retractable.
By the way, the mirror arms are very precise pieces of machinery, designed to
move the mirrors into exactly the right position, but they each have many
degrees of freedom, to allow for adjustments if necessary.
Isn't COSTAR on the JHU campus (or at least pictures of it)? Would it be
possible for you to go take a look and report?
John Roberts
roberts@cmr.ncsl.nist.gov
------------------------------
Date: Sat, 21 Nov 1992 07:26:54 GMT
From: Ron Baalke <baalke@kelvin.jpl.nasa.gov>
Subject: Magellan Update - 11/20/92
Newsgroups: sci.space,sci.astro,alt.sci.planetary
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
November 20, 1992
1. Magellan continues to operate normally, performing a
starcal (star calibration) and desat (desaturation of
the reaction wheels) on each orbit and transmitting a
carrier plus 40 bps X-band signal.
2. The spacecraft has completed 6136 orbits of Venus; 500 so
far in Cycle 4, which will end on May 25, 1993.
3. Tuesday, November 17, the project conducted a design
review of an aerobraking experiment to be conducted at
the end of Cycle 4. Preliminary modeling of dynamic
pressures, temperatures and attitude control indicate
that circularizing the orbit on an aerobraking plan which
proceeds aggressively for the first several weeks, and
backs off in the later stages, appears to be very
feasible.
4. A Spacecraft Team Technical Interchange Meeting (TIM) was
held on Thursday. The spacecraft performance has been
excellent since the last TIM although there have been 12
TWTA (Traveling Wave Tube Ampilfier) SSOs (Spurious Shutoffs),
including five on Tuesday, and there has been some increase
in the slippage of the Solar Array Drive Mechanism since the
end of the apoapsis occultation season.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Learn to recognize the
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | inconsequential, then
|_____|/ |_|/ |_____|/ | ignore it.
------------------------------
Date: Sat, 21 Nov 1992 07:29:39 GMT
From: Ron Baalke <baalke@kelvin.jpl.nasa.gov>
Subject: Mars Observer Update - 11/20/92
Newsgroups: sci.space,sci.astro,alt.sci.planetary
Forwarded from:
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
MARS OBSERVER MISSION STATUS
November 20, 1992
All spacecraft subsystems are performing well.
A new flight sequence, primarily dedicated to radio science
activities, began on Nov. 17 and will continue through Dec. 14.
Checkout of the Thermal Emission Spectrometer and completion of
the Laser Altimeter checkout were performed last week. The Mars
Observer Camera "bakeout" to prepare the instrument for operation
continues through Dec. 28.
The second trajectory correction maneuver (TCM-2) has been
rescheduled for Feb. 8, 1993, to allow engineers time to upgrade
on-board flight software. TCM-3 has also been rescheduled for
March 8, 1993.
Until now, the spacecraft's solar panels have been oriented
at a 60-degree sun incidence angle to prevent excess power caused
by the solar array's direct exposure to the sun. A star-
ephemiris table was uploaded on Nov. 17, decreasing the sun
incidence angle by 5 degrees. These periodic changes will occur
about once a week through Jan. 2, 1993, and will cause the
spacecraft's high-gain antenna to point directly at Earth.
Today the spacecraft is about 16 million kilometers (10
million miles) from Earth, traveling at a speed of about 14,500
kilometers per hour (9,000 miles per hour) relative to Earth.
The spacecraft is traveling at a heliocentric velocity of about
111,500 kilometers per hour (70,000 miles per hour).
#####
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Learn to recognize the
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | inconsequential, then
|_____|/ |_|/ |_____|/ | ignore it.
------------------------------
Date: Fri, 20 Nov 1992 21:28:52 GMT
From: Josh 'K' Hopkins <jbh55289@uxa.cso.uiuc.edu>
Subject: ROTATION OF THE MOON
Newsgroups: sci.space
labmas@stein.u.washington.edu (Michael Andersson) writes:
>In article <1992Nov19.144441.5498@col.hp.com> dag@col.hp.com (David Geiser) writes:
>>> The same thing is happening, much more slowly, to the earth --
>>> friction with the tides and within the "solid" earth is slowing the
>>> rotation rate by something on the order of 1 sec every century. We can
>>> actually measure it (the slowdown) nowadays. Love those atomic clocks!
>>
>>Do you know if that rate is constant? Say around 63M years ago,
>>around the time of the end of the dinosaurs, the day would have
>>been 175 hrs longer!
>No. If the rotation is slowing, then days used to be shorter.
Right, so the rate obviously isn't constant or the Earth would have been
spinning at relativistic speeds shortly before our astraulopithic ancestors
appeared. Since the rates depends on tides and gravitational fields it's very
likely that there are exponential terms in the equation. If I recall correctly,
you have cubics in the formula for tidal forces, which results in a much
different curve than trying to plot it linearly.
--
Josh Hopkins jbh55289@uxa.cso.uiuc.edu
"Why put off 'til tomorrow what you're never going to do anyway?"
------------------------------
Date: 20 Nov 1992 23:21:33 GMT
From: "David M. Palmer" <palmer@cco.caltech.edu>
Subject: ROTATION OF THE MOON
Newsgroups: sci.space
jbh55289@uxa.cso.uiuc.edu (Josh 'K' Hopkins) writes:
>labmas@stein.u.washington.edu (Michael Andersson) writes:
>>>Do you know if that rate is constant? Say around 63M years ago,
>>>around the time of the end of the dinosaurs, the day would have
>>>been 175 hrs longer!
>>No. If the rotation is slowing, then days used to be shorter.
>Right, so the rate obviously isn't constant or the Earth would have been
>spinning at relativistic speeds shortly before our astraulopithic ancestors
>appeared. Since the rates depends on tides and gravitational fields it's very
>likely that there are exponential terms in the equation. If I recall correctly,
>you have cubics in the formula for tidal forces, which results in a much
>different curve than trying to plot it linearly.
I have heard (potential Urban Legend warning) that one of the ocean basins
(Pacific? Atlantic?) has a slosh frequency which is resonant with the
tides, which greatly increases the tidal drag. In the past, the continents
were at different positions, so the oceans had different frequencies,
so the tidal drag was much less.
eno
--
David Palmer palmer@alumni.caltech.edu
------------------------------
Date: Fri, 20 Nov 92 20:42:27 GMT
From: Ross Borden <borden@sol.UVic.CA>
Subject: shuttle computers
Newsgroups: sci.space
>In article <Bxwy52.G3o.1@cs.cmu.edu> roberts@cmr.ncsl.nist.gov (John Roberts) writes:
>>Is it at all possible to reprogram the GPCs from the ground, or does it
>>have to be done from onboard?
>
>They are routinely reloaded with different software from onboard storage
>(tape, I think), but I don't think there is any remote-upload capability.
>In an emergency, the astronauts can input patches manually -- NASA insisted
>on this capability, over IBM's objections (the IBM folks say they considered
>having the patch routine pop up a little flag saying "your warranty is void"
>when it was used :-)) -- but that's not suitable for routine use.
>--
>MS-DOS is the OS/360 of the 1980s. | Henry Spencer @ U of Toronto Zoology
> -Hal W. Hardenbergh (1985)| henry@zoo.toronto.edu utzoo!henry
>
>------------------------------
Do the GPC's have hard drives? If so, how do they guard against
shock, vibration, etc?
_______________________________________________________________________________
| .sig? I don't need no stinking .sig! |
| rborden@ra.uvic.ca |
-------------------------------------------------------------------------------
------------------------------
Date: Fri, 20 Nov 1992 20:10:23 GMT
From: Steven Bellovin <smb@ulysses.att.com>
Subject: Shuttle replacement
Newsgroups: sci.space.shuttle,sci.space
In article <1992Nov20.155202.16554@murdoch.acc.Virginia.EDU>, rbw3q@rayleigh.mech.Virginia.EDU (Brad Whitehurst) writes:
> If you are using well tested current technology, why should
> the gov't. pay for any of the craft?
> ....
> But if your claim to fame is that you can do all the transportation
> using current technology and are not pushing the envelope, then
> convince private concerns that they'll turn a profit, and invest in it
> themselves. If GD, McD, Boeing and the rest really wanted to, they
> could put enough heat on NASA to convince NASA to leave the "space
> truck" market altogether.
The question is whether or not there's enough profit to recoup that kind
of up-front development. In the space market, I sincerely doubt it,
unless the launch rate goes *way* up (see below). Even designing new
jetliners is dicey these days; Boeing and McDonald-Douglas have brought
in outside partners for their newest planes to cut their costs and risks.
They've got to sell *hundreds* of planes to make a profit on their total
expenses including development.
As for the launch rate going up -- not any time soon, because of a
feedback loop. Because launches are so expensive, folks design complex,
gold-plated, neutronium-armored satellites. That, of course, means they
can't build very many of them. If launches were suddenly cheaper, folks
could build different satellites -- but until they do, there won't be
enough launches to achieve much economy of scale. (Btw, to see what I
mean, contrast the (ex-)Soviet spy satellite philosophy with the U.S.'s.)
------------------------------
Date: 20 Nov 1992 18:23 CST
From: wingo%cspara.decnet@Fedex.Msfc.Nasa.Gov
Subject: Shuttle replacement
Newsgroups: sci.space.shuttle,sci.space
In article <1992Nov19.144842.23088@iti.org>, aws@iti.org (Allen W. Sherzer) writes...
>In article <BxxDL7.9Ly@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes:
>
>>>The US shouldn't be putting it's money into the design of ANY expendable
>>>launcher. We have done that for too long and it's hasn't reduced launch
>>>costs by a dime.
>
>>Actually, this isn't a very sound argument.... [Henry goes on to say
>>that it hasn't been tried and examples from China and Russia show it
>>CAN be a lot cheaper]
>
>Allow me to rephrase: NASA has shown that it cannot execute large multi-year
>multi-billion $$ projects in a cost effective manner. Some blame for this
>goes to Congress, and some to NASA. Asking them to do it again will simply
>waste more money and delay the creation of a spacefaring civilization.
>
No Allan, what has been shown is that when you micromanage a program and or
cut the budget below the request and or stretch the program to "save money"
Nasa nor anyone else for that matter can complete a job in a cost effective
manner. There are many NASA programs that have been completed on time and
under budget WHEN that whole budget has been provided AND no recissions or
redesigns or other crap has been foisted on the program.
>I don't doubt that much cheaper expendables CAN be build (Zenith Star
>launchers for example cut costs in half). I simply don't believe that the US
>government can build them.
>
The baby saturn can do the same thing. Funny thing is that the NLS 1 design
ended up in the single engine configuration that we propose for the Baby
Saturn. Oh by the way I have confirmed the existence of at least 8 well
preserved Saturn F1 engines at the Marshall Space Flight center. They are
doing some work on them. However it looks like the cost of refurbing the
F1 test stand is a bit high to implement right now.
By the way Henry, I found out some interesting stuff there are three versions
of the Saturn V first Stage. These are as follows
S1C-T Test Stage for Manufacturing and Ground firings
This is the one at the Alabama Space & Rocket Center
S1C-D Dynamic Test model. Was later scrapped at the end of
the program.
S1C-1,2,3.... Flight Saturn S1 C stages.
------------------------------
Date: 20 Nov 1992 12:59 PST
From: SCOTT I CHASE <sichase@csa3.lbl.gov>
Subject: Solar Sailing
Newsgroups: sci.space
In article <N4HY.92Nov20111535@wahoo.UUCP>, n4hy@wahoo.UUCP (Bob McGwier) writes...
>
>I have a local high school student asking me for information on Solar
>sailing. I have programs that will allow him to manipulate the sail
>if I knew how to calculate `thrusts' etc. from the photon pressure.
>Any details you care to send, primarily references, that will allow me
>to help this very bright student, I would appreciate it.
>
>Please use EMAIL. I will summarize replies that contain useful information.
I tried to E-mail, and failed. Here's some incomplete information
which might be useful.
It's fairly straightforward to calculate the force on your sail
from solar radiation pressure. Here's a back-of-the-envelope calculation
which ignores some details. Consider an individual photon hitting
your sail. It has total momentum p = h*lambda, where h is planck's constant
and lambda is the wavelength. By totally reflecting off your sail,
you get a total momentum change of dp = 2*p. To calculate the total
pressure from the Sun on a sail of area A at distance D from the Sun,
you need only to know the total solar luminosity, L = 3.8x10^26 Joules/sec.
If your sail makes an angle theta with respect to the Sun, it has
an effective area of A*cos(theta), and intercepts a total fraction f
of the light, where
f = A*cos(theta)/(4*pi*D^2),
so a total photon energy of E = f*L hits it. Now, for a photon, E = pc,
where c = 3x10^8 m/s, so you can find the total momentum of the light
hitting your sails and p = E/c, and then your total momentum change per
second is 2*p. Your acceleration is then 2*p/m, where m is your ship's
mass, directed away from the Sun.
There is more to Solar sailing, however, than just the radiation pressure.
The Solar wind contains massive particles which will also hit your
sail. I don't have data handy for what the flux is, but you would
need to look it up and make some kind of correction for it. It might
even dominate! It will be much harder to calculate the effects of
the proton wind on your sail, since the protons will pass through your
sail, imparting only some of their kinetic energy. It gets messy, as
the energy loss fraction will depend upon the atomic composition of your
sail and the energy distribution of the protons. I can work up some
estimates if you want them.
-Scott
--------------------
Scott I. Chase "It is not a simple life to be a single cell,
SICHASE@CSA2.LBL.GOV although I have no right to say so, having
been a single cell so long ago myself that I
have no memory at all of that stage of my
life." - Lewis Thomas
------------------------------
Date: Fri, 20 Nov 1992 20:47:05 GMT
From: david michelson <davem@ee.ubc.ca>
Subject: space news from Oct 23 Science (not AW&ST)
Newsgroups: sci.space,alt.sci.planetary
In article <2421@usna.NAVY.MIL> wdw@math2.sma.usna.navy.MIL (Wm. Douglas Withers -- math FACULTY <wdw@sma.usna.navy.mil>) writes:
>
>I wonder why the same techniques can't be used to shed light on the question
>of the presence of ice at the Moon's poles. Comments, anyone?
>
It's a matter of the relative inclination of the orbits of Mercury and Earth.
From Slade, Butler, and Muhleman, ``Mercury Radar Imaging: Evidence for Polar
Ice,'' Science, 258, 635--640, 23 Oct 1992:
"On both days, the sub-earth latitudes were far enough north for our
instruments to see over the north pole and into areas thought to be
permanently shadowed from the sun."
Figures 1 and 3 in Harmon and Slade, "Radar Mapping of Mercury..." which
follows immediately after the Slade et al. paper, make this very clear.
We simply can't see the moon from the same aspect from the earth's surface.
We *really* need to get a lunar polar orbiting geochemical mapper built and
launched!
--
Dave Michelson
davem@ee.ubc.ca
------------------------------
Date: Fri, 20 Nov 1992 21:07:06 GMT
From: Dan Vento <vento@mars.lerc.nasa.gov>
Subject: Space suit research?
Newsgroups: sci.space
In article <1992Nov17.033954.4419@ucsu.Colorado.EDU>,
fcrary@ucsu.Colorado.EDU (Frank Crary) wrote:
>
> Actually, Vail or Aspen at ~10 psi average, would be a better example
> than Denver (~12 psi...) I have never understood why NASA doesn't
> consider this fact relevant. I know the reason the Case for Mars IV
> conference endorsed 14.5psi for Mars missions: NASA apparently likes
> it and will probably be using that pressure in many existing systems
> by the time a Mars mission is launched. Having two different pressures
> is a _major_ pain, so the general consensus was to stick to 14.5psi...
>
> Frank Crary
> CU Boulder
Another reason that NASA does not like low pressure high oxygen (e.g. 5 psi
pure oxygen) is the danger of fires in the crew cabin while in orbit. Most
materials don't burn easily in low g in "normal" air. Enriched oxygen
environments can be a serious problem for materials flammability. Needless
to say, this is a big driver in any decisions to be made about the cabin
environment for manned flight.
Dan Vento
vento@mars.lerc.nasa.gov
------------------------------
Date: Fri, 20 Nov 92 22:35:42 EST
From: John Roberts <roberts@cmr.ncsl.nist.gov>
Subject: Space suit research?
-From: fcrary@ucsu.Colorado.EDU (Frank Crary)
-Subject: Re: Space suit research?
-Date: 20 Nov 92 22:39:24 GMT
-Organization: University of Colorado, Boulder
-I wasn't suggesting enriched oxygen: A 10 psi, 20% oxygen atmosphere
-should be perfectly acceptable. That's less oxygen than at sea level,
-but certainly enough to support people (even physically active people).
-Since there are cities with this sort of partial pressure of oxygen,
-and people, in fact, go there to be physically active (ski), I'd say
-there is considerable evidence that this isn't a health problem.
Apparently anything significantly below 3 psi partial pressure of oxygen
is a potential health risk, unless you have many generations of ancestors
who lived in the mountains. The body undergoes various changes to adapt to
low oxygen content, but some of these changes have undesirable side effects.
I'll try to find that Scientific American article again and post a summary.
John Roberts
roberts@cmr.ncsl.nist.gov
------------------------------
Date: Fri, 20 Nov 92 23:04:48 EST
From: John Roberts <roberts@cmr.ncsl.nist.gov>
Subject: Space suit research?
-From: ewright@convex.com (Edward V. Wright)
-Subject: Re: Space suit research?
-Date: 20 Nov 92 16:51:24 GMT
-Organization: Engineering, CONVEX Computer Corp., Richardson, Tx., USA
-In <Bxs6ou.2F4.1@cs.cmu.edu> roberts@cmr.ncsl.nist.gov (John Roberts) writes:
->-or are there long term bio effects????
->There *may* be. For example, one of the Apollo astronauts, after a busy day
->on the moon, had bleeding under his fingernails - thought to be mainly a
->result of the low pressure. Little indications like that made NASA uneasy. :-)
-I can't see any reason why low pressure would cause bleeding under the nails
-as long as the pressure inside the body was equally low. Sounds like NASA
-was worried about a pressure leak in the gloves, causing the pressure there
-to be lower than the pressure in the rest of the suit. That could, quite
-likely, cause bleeding, with the pressure inside the body pushing a small
-amount of blood through the skin under the nails (which is quite thin).
Clearly, in non-toxic atmospheres of 1 Atm pressure or less, the main
physiological consideration is the partial pressure of oxygen. Here are
some *speculations* on ways in which the absence of gases other than
oxygen might make a difference:
# The internal body fluid differential pressures (and the range in blood
pressure with the pulse) are a much larger fraction of the pressure of
a 3 psi O2 atmosphere. (I'm not sure of any specific mechanism by which
that would make a difference, but I don't think we can casually dismiss
it as "obvious" that this wouldn't be a potential problem.)
# Given the vapor pressure of the body fluids, I would think the rate of
drying could be significantly increased. (Didn't somebody post that the
Apollo astronauts had problems in this respect?)
# Since the blood interacts much more strongly with oxygen and CO2 than
with nitrogen, I would expect the air flow mechanisms within the lungs
to be noticeably different.
As I said, these are speculations. While oxygen content is the main
concern, there *are* differences in a low-pressure, high-oxygen environment.
One or more of these differences could produce effects that are subtle, but
significant over the long run.
Evidently, NASA isn't sure either. :-)
John Roberts
roberts@cmr.ncsl.nist.gov
------------------------------
Date: Fri, 20 Nov 1992 22:39:24 GMT
From: Frank Crary <fcrary@ucsu.Colorado.EDU>
Subject: Space suit research?
Newsgroups: sci.space
In article <vento-201192160142@elwood.lerc.nasa.gov> vento@mars.lerc.nasa.gov (Dan Vento) writes:
>> Actually, Vail or Aspen at ~10 psi average, would be a better example
>> than Denver (~12 psi...) I have never understood why NASA doesn't
>> consider this fact relevant.
>Another reason that NASA does not like low pressure high oxygen (e.g. 5 psi
>pure oxygen) is the danger of fires in the crew cabin while in orbit. Most
>materials don't burn easily in low g in "normal" air. Enriched oxygen
>environments can be a serious problem for materials flammability.
I wasn't suggesting enriched oxygen: A 10 psi, 20% oxygen atmosphere
should be perfectly acceptable. That's less oxygen than at sea level,
but certainly enough to support people (even physically active people).
Since there are cities with this sort of partial pressure of oxygen,
and people, in fact, go there to be physically active (ski), I'd say
there is considerable evidence that this isn't a health problem.
Frank Crary
CU Boulder
------------------------------
Date: Fri, 20 Nov 1992 22:36:32 GMT
From: "Edward V. Wright" <ewright@convex.com>
Subject: SSTO viability
Newsgroups: sci.space
In <BxznD4.84I.1@cs.cmu.edu> roberts@cmr.ncsl.nist.gov (John Roberts) writes:
>What *I'd* like to know is why geese feel it necessary to honk frequently
>as they fly along, and what perhaps 50% of them know about Canada, that
>they refuse to go there even in the summer! :-)
Since you say geese are like bicycle riders, I'd guess they honk for the
same reasons as most cyclists I've seen. To warn some hapless pedestrian
that he's about to be run down from behind. :-)
------------------------------
Date: Fri, 20 Nov 1992 16:04:59 GMT
From: Ed Beshore <edb@hpgrla.gr.hp.com>
Subject: Re: FREE-ENERGY TECHNOLOGY For Spacecraft
Message-Id: <2970001@hpgrla.gr.hp.com>
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There are a couple of fascinating things about Mr. McElwaine's postings.
1. I love the way such zealots use capitalization in their texts. Somehow
their stuff always reads like a bottle of Dr. Brauner's concentrated soap.
(If you don't know what I'm talking about, ask for it sometime at a
health food/natural products store -- you'll know what I'm talking about
right away.)
2. Another thing that is interesting is everyone else's reactions to him. Instead
of considering him an amusing three sigma kind of character, people use much
more net capacity trying to figure out how to silence him or flaming his
posts. I propose someone post a small chunk of code to filter an author
from a notes file. If you don't want to read someones posts, then you
can let your coomputer do the clipping.
Otherwise, consider him a colorful amusement...
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Edward Beshore
Hewlett Packard Company Voice: (303) 350-4826
700 71st Avenue FAX: (303) 350-4675
Greeley Colorado, 80634 email: edb@hpgrla.gr.hp.com
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End of Space Digest Volume 15 : Issue 444
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