Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V16_3/V16NO388.TXT

Internet Message Format | 1993-07-13 | 34KB

Date: Tue, 30 Mar 93 05:41:20
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V16 #388
To: Space Digest Readers
Precedence: bulk


Space Digest                Tue, 30 Mar 93       Volume 16 : Issue 388

Today's Topics:
                  Alaska Pipeline and Space Station!
                          Artificial Gravity
            Budget Astronaut (was: Idle Question) (2 msgs)
                            Craf's Budget
                         Magellan Venus Maps
                   More water simulations (3 msgs)
                            nuclear waste
                    Pres. Clinton's E-mail Address
                           SSF Redesign....
                  Status of U.S./Soviet Cooperation
       the call to space (was Re: Clueless Szaboisms ) (3 msgs)
                 US Satellite Crashing on Brisbane??
                         Why is Venus so hot?

    Welcome to the Space Digest!!  Please send your messages to
    "[e-mail]", 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 [e-mail] (Internet).
----------------------------------------------------------------------

Date: 29 Mar 93 23:39:32 GMT
From: Henry Spencer <[e-mail]>
Subject: Alaska Pipeline and Space Station!
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>Governments don't have to be the only ones who can put crafts into space and
>such.. Private enterprise built the Alaska Pipeline, with little or no
>government direct help.. So why not have a group of private corps build a space
>station? why can't they the private corps do it, like they did with the Alaska
>Pipeline...??

Fine idea, but where's the market?  Answer:  the government... which does
not *want* it built privately, because that would mean smaller bureaucratic
empires and lots of unemployed aerospace workers.

At current prices, there is little private market for a station.  It's
mostly government-funded research or direct government activities.

Getting billions of dollars of private investment is no big trick, if there
is essentially no uncertainty about getting a substantial long-term payback.
For something highly speculative, with little assured near-term market, the
available money is much smaller.

The US government historically has been most unwilling to just set the
performance specs and guarantee the market for spaceflight.  (It's been
done with enormous success in other areas, notably aviation.)  NASA and
DoD like being in control and have been dragged kicking and screaming
into most of the handful of service purchases they've done of late.
And Congress almost never makes financial commitments more than one year
ahead, because they like meddling and their attention span is short.

US spaceflight is a tight little socialist empire that is fiercely
resisting dismantling; it is yet to be seen whether Goldin will be
Gorbachev or Krushchev.  Orders from Slick Willie saying "cut costs a
lot, but don't fire anybody" sure don't help.
--
All work is one man's work.             | Henry Spencer @ U of Toronto Zoology
                    - Kipling           |  [e-mail]  utzoo!henry

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

Date: 29 Mar 93 23:44:39 GMT
From: Henry Spencer <[e-mail]>
Subject: Artificial Gravity
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (John S. Neff) writes:
>I recall that the Apollo astronauts would rotate their capsule about the
>long axis for thermal control, they called it the "barbecue mode." Does
>anyone know what the artifical g force was when they were doing this?

Utterly negligible; the spin rate was very slow.

>A thuster on a Gemini capsule came on, by error, and spun up the capsule.
>It was said at the time that if the astronauts has not shut the thuster off
>they might have blacked out. This suggest rather high values of g are
>possible with relatively small spacecraft.

This was a pretty fast spin, and being spun more or less around your body
center is not good for you.

The problem is that spin rates higher than circa 2 RPM (the limits are
poorly known) will probably cause inner-ear problems due to Coriolis
forces and the like.  The spin radius needs to be long, and the spin
rate correspondingly low, before the "gravity" gradient encountered in
motions of a few meters -- e.g. people moving around -- becomes negligible.
5 RPM is too much.  3 might be okay with selected crews who didn't go
from rotating to unrotating sections too often.  You might have to go as
low as 1 if you wanted no crew-selection constraint and free movement.
--
All work is one man's work.             | Henry Spencer @ U of Toronto Zoology
                    - Kipling           |  [e-mail]  utzoo!henry

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

Date: 30 Mar 93 00:02:33 GMT
From: Henry Spencer <[e-mail]>
Subject: Budget Astronaut (was: Idle Question)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>: Scout is rated at 475 pounds to a 300 km orbit. It has lofted as much
>: as 522 pounds to LEO.
>
>A) How big is the absolute minimum atmospheric re-entry and life
>support module for the aspiring low-cost astronaut? ...

George Herbert estimated a minimum one-man capsule as just feasible
for the new stretched Pegasus, which puts Scout out of the running unless
you can beat George's weight numbers substantially.  (Probably possible,
but maybe only by fairly radical methods.)

>B) Would it be legally possible for some rich soul to book a Scout
>flight for a couple of unmanned tests, then the final manned flight?
>Would a "man rating" of the Scout stand in the way?

There is no *fundamental* legal obstacle.  However, all space launches
involving US citizens need approval from the Office of Commercial Space
Transportation, and they are *not* required to restrict their considerations
to safety of innocent bystanders.  You might have trouble on this one.

You also have to talk LTV into it, of course, which might require waving
considerable amounts of money under their nose.  They don't have to give
a reason for refusing to sell to you.  There is also the small matter of
the Scout production line having been closed down quite a while ago...
--
All work is one man's work.             | Henry Spencer @ U of Toronto Zoology
                    - Kipling           |  [e-mail]  utzoo!henry

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

Date: 30 Mar 93 00:07:16 GMT
From: Henry Spencer <[e-mail]>
Subject: Budget Astronaut (was: Idle Question)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (John S. Neff) writes:
>My recollection is that the acceleration of a Scout is very high. Someone
>told me that it has supersonic velocity a few second after launch...

Nope, the highest acceleration is just before either third- or fourth-stage
burnout, depending on the payload.  For heavy loads it's just under 8G.  No
fun, but unlikely to cause serious injury.
--
All work is one man's work.             | Henry Spencer @ U of Toronto Zoology
                    - Kipling           |  [e-mail]  utzoo!henry

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

Date: Tue, 30 Mar 1993 00:18:21 GMT
From: Henry Spencer <[e-mail]>
Subject: Craf's Budget
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Tom) writes:
>>Because Congress gave CRAF/Cassini an absolute total overall budget cap...
>>something that has not been done for most other projects, including Fred.
>>Few NASA projects, manned or unmanned, would survive to fly if they had
>>firm budget limits.  Overruns are a way of life for NASA space projects.
>
>So why the change?  When you say 'congress', do you mean all of them, for
>this particular project, suddenly got fiscally concious, only to forget the
>whole discipline thing for the next project that came down the pike? ...

Fred starting coming the pike a long time before CRAF/Cassini, and has
gained a lot of political momentum that would hamper any Congressional
attempt to set a budget cap.

I think it is pretty likely that almost any major NASA project approved
by Congress *in future* will have a cap.

Incidentally, it's not just manned projects that have these overruns.
One reason why Congress got cranky about CRAF/Cassini was what happened
with Mars Observer and Galileo.  (The planetary people got gored somewhat
by shuttle overruns, but it didn't help at all that Galileo was having
massive overruns at the same time.)
--
All work is one man's work.             | Henry Spencer @ U of Toronto Zoology
                    - Kipling           |  [e-mail]  utzoo!henry

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

Date: 30 Mar 1993 00:34 UT
From: Ron Baalke <[e-mail]>
Subject: Magellan Venus Maps
Newsgroups: sci.space,sci.astro,alt.sci.planetary

                         ==========================
                             Magellan Venus Maps
                               March 29, 1993
                         ==========================

Three more Magellan Venus maps are now available in GIF and JPEG formats.
These maps are courtesy of Peter Ford from MIT, working on the Magellan
Project.  They were made from the altimeter and radiometer data from
all 3 Magellan radar mapping cycles (24 months of operation).  The maps
are shown in Mercator projection for the regions of the planet between
69 degrees north and 69 degrees south latitude, and in stereographic
projections for the polar regions.  The images have been anti-aliased
in order to make their embedded text readable, and have been reduced to
820x820 pixel, 256 color resolution.  Caption files accompanying the
images are also included.  The images are available using anonymous ftp
to:

        ftp:      ames.arc.nasa.gov (128.102.18.3)
        user:     anonymous
        cd:       pub/SPACE/GIF
        files:    gedrp3v2.gif (Microwave Emissivity Map)
                  gedrp3v2.txt
                  gsdrp3v2.gif (Average Meter-Scale Slope Map)
                  gsdrp3v2.txt
                  gtdrp3v2.gif (Topography Map)
                  gtdrp3v2.txt

        cd:       pub/SPACE/JPEG
        files:    gedrp3v2.jpg (Microwave Emissivity Map)
                  gedrp3v2.txt
                  gsdrp3v2.jpg (Average Meter-Scale Slope Map)
                  gsdrp3v2.txt
                  gtdrp3v2.jpg (Topography Map)
                  gtdrp3v2.txt

---------------------------------------------------------------------
gedrp3v2.txt

These maps of Venus show how well various regions of the surface
radiate heat compared to a perfect radiator.  They display in color a
quantity called emissivity, observed using a Magellan Synthetic
Aperture Radar (SAR) receiver during its 24 months of systematic
mapping in Venus orbit.  Color is used to code the emission efficiency
(see color bar).  Red corresponds to the highest, blue to the lowest
values of emissivity.  The upper image shows the portion of the planet
between 69 degrees north and 69 degrees south latitude in Mercator
projection; beneath it are the two polar regions covering latitudes
above 44 degrees in stereographic projection.  The horizontal
resolution varies with latitude, being determined solely by the
"footprint" of Magellan's high-gain SAR antenna beam.  Near the equator
the surface resolution is about 20 kilometers (12.4 miles) but at high
latitudes it degrades to as much as 100 kilometers (62 miles).
Emissivity of the surface is a measure of how well the surface radiates
heat.  Higher regions, such as the Maxwell Montes (at top left center)
and Aphrodite Terra (along the equator at right center), usually show
lower values of emissivity than are typical of lower-lying areas.  On a
cooler planet, such as Earth or Mars, water or ice might explain the
puzzling observations but at the surface temperature of Venus -- 470
degrees C (878 F) -- neither can be present.  Some theories call for
the presence of an electrically-conducting mineral such as pyrite (the
minerals have an electrical field when illuminated by radar); others
suggest a material as yet unidentified that has an extremely low
electrical loss.  The data shown here were compiled and analyzed at the
Center for Space Research, Massachusetts Institute of Technology.
---------------------------------------------------------------------
gsdrp3v2.txt

These images display the meter-scale roughness of the Venus surface
(characterized by its root-mean-square average slope), as observed by
the Magellan radar altimeter during its 24 months of systematic
mapping.  The lightest shades locate areas having the highest values of
roughness, while darker shades indicate areas that are smoother.  The
upper image shows that part of the planet between 69 degrees north and
69 degrees south latitude in Mercator projection; beneath it are the
two polar regions covering latitudes above 44 degrees in stereographic
projection.  Easterly longitudes run across the Mercator map from left
to right, and around the periphery of the polar stereographic
projections.  Resolution of the surface varies with spacecraft
altitude, being about 10 kilometers near the equator and degrading to
as much as 25 kilometers at high latitudes.  Black areas indicate where
data were not obtained by Magellan.

There is a tendency for elevated regions, e.g. the Maxwell Montes (at
top center) and Aphrodite Terra (along the equator at right), to show
steeper meter-scale slopes than are typical of lower-lying areas.  The
steeper slopes probably result from disruption of the surface
associated with tectonic activity in these regions.  Note the large
2300-kilometer (1400-mile) diameter circular feature (Artemis Chasma)
in the lower right of the Mercator image. This feature is thought to
have been caused by a gigantic plume of heated rock rising from the
planet's interior.  The data shown here were compiled and analyzed at
the Center for Space Research, Massachusetts Institute of Technology.
---------------------------------------------------------------------
gtdrp3v2.txt

This map of the topography of Venus was obtained by the Magellan radar
altimeter during its 24 months of systematic mapping.  Color is used to
code elevation (see color bar), and simulated shading to emphasize
relief.  Red corresponds to the highest, blue to the lowest
elevations.  The upper image shows the portion of the planet between 69
degrees north and 69 degrees south latitude in Mercator projection;
beneath it are the two polar regions covering latitudes above 44
degrees in stereographic projection.  Height accuracy is better than 50
meters; horizontal ("footprint") resolution of the surface depends on
spacecraft altitude, with a resolution of about 10 kilometers (6 miles)
near the equator and as much as 25 kilometers (15.5 miles) at higher
latitudes.  The Magellan altimeter acquired topography data over 98
percent of the planet's surface.  Gray areas show the coarser results
from the Pioneer Venus (1978) and Venera 15/16 (1983) radar altimeters,
and indicate where data were not obtained by Magellan.  The elevated
region in the north is Ishtar Terra, dominated by Maxwell Montes (the
planet's highest mountains) which rise 11 kilometers (36,000 feet)
above the planetary mean elevation.  Southwest of Ishtar are the
highlands of Beta Regio and Phoebe Regio, which are bisected by a major
north-south trending rift zone.  The scorpion-shaped feature extending
along the equator between 70 and 210 degrees longitude is Aphrodite
Terra, a continent-like highland that contains several spectacular
volcanoes at its eastern limit: Maat, Ozza and Sapas Montes.  The
altimetric data shown here were compiled and analyzed at the Center for
Space Research, Massachusetts Institute of Technology.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Don't ever take a fence
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | down until you know the
|_____|/  |_|/       |_____|/                     | reason it was put up.

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

Date: 29 Mar 1993 23:42:20 GMT
From: Dave Akin <[e-mail]>
Subject: More water simulations
Newsgroups: sci.space

In article <1p7qgb$[e-mail]> Dave McKissock,
[e-mail] writes:
>>> When we practise the EVA's in the water tanks... We utilize
>>> astronauts, who HAVE ON-ORBIT EVA EXPERIENCE. Thus, we are asking
>>> somebody who "has been there" to gauge the acceptability of our
>>> suggested EVA tasks.
>>
>>I understand that Intelsat didn't use the tanks. But tell me, did they
>>have astronauts who HAVE ON-ORBIT EVA EXPERIENCE sign off on the
>>procedure? If not, why not and if so, how do you explain that it
>>failed to go as planned? Did they sign off on Solar Max and the others?
>
Again, the training applicable to the Intelsat retrieval
(specifically, the use of the capture bar that didn't work on-
orbit) was done with the astronaut in 1-G, and using an air-
bearing full-scale simulation of the Intelsat back end. I
don't believe there was ever any pretense that the dynamics
were completely accurate, just the best that could be done
within time and cost constraints for flight training. You
can't blame Intelsat (can you "blame" an eventual success
on something?) on neutral buoyancy, because that's not
where that particular phase of training took place.

Astronaut training is almost entirely procedures driven -
when the time comes to do it on-orbit, they want to make
sure therre's no ambiguity on "what to do next". To the
extent that dynamics can be accurately simulated, they may
be (based on the perceptions of difficulty, based on prior
experience), but the primary thing is to make sure the
_procedures_ are understood and familiar. And that's
usually more than enough...
>
>>No, I'm not an astronaut; just a lowly engineer. However when I see that
>>none of the satellite rescues/repairs have gone as planned or how they
>>should have (according to the simulations) I tend to question the
>>simulations. I woldn't throw out the simulations, simply understand
>>that there is a lot we don't understand. My solution would be to
>>do more EVA experiments so errors in the simulations can be identified
>>and quanified. NASA now seems to agree with this view.
>
>I wasn't aware that NASA agreed that "more EVA experiments [are
>needed] so errors in the simulations can be identified and quantified".
>
>I thought we agreed to perform more EVAs on upcoming Shuttle flights,
>because someone looked at a plot of planned EVA hours versus
>Shuttle missions, and noted that with SSF many hours of EVA are
>needed for maintenance and assembly. So, rather than having a
>step change in EVA hours, they would gradually build-up the use
>of EVA.
>
>I don't believe anybody from NASA agreed to build mass simulators,
>for example, of SSF modules, and have the astronauts practise
>EVAs with them. I thought the planned EVAs were to be simple, low
>budget affairs (like the last one, where one astronaut simply
>carried the other one around the cargo bay).

Yeah, although there are some attempts to do "basic
research", the ONLY reason this new policy has gone into
effect is the desire to increase the NUMBER of people in
the crew office with EVA experience. (NASA HQ
mandated that all four crew assigned to the Hubble
refurbishment mission this December should be EVA
veterans. At the time, there were only nine active flight
crew who had already gone EVA. Limits your options for
flight assignments...) Considering the requirements on
everybody associated with a complex EVA like Hubble
(flight crew, controllers, and trainers), it's a real good idea
to let them get their initial experience on "easy" missions
like these familiarization EVAs.

  - Dave Akin
     Director, University of Maryland Space Systems Lab

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

Date: 29 Mar 1993 18:47:07 -0500
From: Pat <[e-mail]>
Subject: More water simulations
Newsgroups: sci.space

Dave,

    Dont tell me that It's easier to post from cleveland freenet
then from work?  Boy you must ahve a slow feed there at lewis.

pat

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

Date: 30 Mar 93 00:10:24 GMT
From: Henry Spencer <[e-mail]>
Subject: More water simulations
Newsgroups: sci.space

In article <1p81gs$[e-mail]> Dave Akin <[e-mail]> writes:
>... (NASA HQ
>mandated that all four crew assigned to the Hubble
>refurbishment mission this December should be EVA
>veterans. At the time, there were only nine active flight
>crew who had already gone EVA. Limits your options for
>flight assignments...)

Of course, the obvious :-) thing to do is to fly one of the cosmonauts
now in training for a US shuttle flight.  Somebody observed that those
two guys, between them, have almost as much EVA experience as the entire
active NASA astronaut corps...
--
All work is one man's work.             | Henry Spencer @ U of Toronto Zoology
                    - Kipling           |  [e-mail]  utzoo!henry

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

Date: 29 Mar 93 23:51:38 GMT
From: Henry Spencer <[e-mail]>
Subject: nuclear waste
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (William Reiken) writes:
>Why not
>use nuclear waste for powering the thermo-generators that NASA proposes for
>their Mars missions? ...

(1) The total requirement for isotopes for those missions is measured
    in kilograms.  While the hazardous-waste output of nuclear power
    plants *is* miniscule compared to that from fossil-fuel plants,
    it's not *that* miniscule.

(2) They need isotopes with relatively short half-lives and little or no
    gamma emission, so they get a lot of power output in a form that
    is easily converted to heat.

(3) It is really not that difficult to deal with nuclear waste satisfactorily.
    The problems of deep burial are political, not technical.
--
All work is one man's work.             | Henry Spencer @ U of Toronto Zoology
                    - Kipling           |  [e-mail]  utzoo!henry

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

Date: 29 Mar 93 23:53:36 GMT
From: Henry Spencer <[e-mail]>
Subject: Pres. Clinton's E-mail Address
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (LINENSCHMIDT, JAMES ROBERT) writes:
>I few weeks ago I caught a glimpse of a message that had Clinton's e-mail
>address.  Does anyone know what it is...

Why bother?  You surely don't think he'll be reading it himself, do you?
--
All work is one man's work.             | Henry Spencer @ U of Toronto Zoology
                    - Kipling           |  [e-mail]  utzoo!henry

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

Date: 29 Mar 93 13:44:36 GMT
From: Pat <[e-mail]>
Subject: SSF Redesign....
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
|Pat ([e-mail]) wrote:
|
|:     PS DOes anyone have a real solid justification for
|: the Alpha gimbbels as opposed to  going solar inertial?
|: and placing any earth sensors into a swing boom?
|Since it doesn't really matter much if the solar panels are a few
|degrees off, and a few degrees are a big deal for Earth Obs and
|astronomy, we decided to put the gimbals on the solar-pointing
|equipment.  So the "real, solid justification" is pointing accuracy.
|
|Hey, but don't mind me.  I'm just a Shuttle guy.


This doesn't seem to be a problem for the SHuttle experiments.

ASTRO  met some reasonable pointing criteria,  and  the atmospheric
payloads, also seem to match  some form of Pointing criteria.

Even if the Boom itself is only within 2 degrees of arc,  can't the instruments
have some form of vernier pointing?

The boom more or less maintains a steady down, and then precision
measuring equipment  determines the off point angle and rapidly
adjusts the final point angle?

The problem with the alpha gimbels, si they have to swing a Large
mass 360 degrees every 90 minutes,  while coping with large thermal
stresses.

If you had a small mass for the EOS payloads,  and the astro payloads,
the criticality is reduced.   We know how to make reliable scan platforms.
Look at voyager.  Sure given the station dynamics,  not everything gets imaged, but
over time,  one can build up a good composite.

ANyway EOS and astronomy are not station primary goals.  Life SCience and
materials are.  It seems kinda strange to torque Station Design characteristics
in order to meet a  tertiary science goal, that can be met on a
reduced scale with a well known technology.

But that's my critique of the entire station.

pat

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

Date: 29 Mar 93 14:39:44 GMT
From: Matthew DeLuca <[e-mail]>
Subject: Status of U.S./Soviet Cooperation
Newsgroups: sci.space

In article <1p5iav$[e-mail]> [e-mail] (Paul Eric Miller) writes:

>It is my impression that it is absolutely criminal that we are not
>taking advantage of the obvious economic advantages to the U.S. of
>contracting out many of our space services to the former Soviets [...]

Is it?  Think about the situation for a moment; the former Soviet space
industry has been fractured into 15 separate independent pieces.  Several
of the resulting nations are either at war with or hostile towards other
former republics.  Some industrial facilities formerly devoted to space
applications are now making toaster ovens.  Launch complex employees are
looting facilities of everything movable.  If you were the U.S. government
or a corporation, how fast would you rush to invest in this situation?

There are a number of good reasons to work with the Soviets in space, but
until the situation stabilizes over there, I seriously doubt any sane
Western organization or government is going to put signifigant money into
any joint projects.
--
Matthew DeLuca
Georgia Institute of Technology, Atlanta Georgia, 30332
uucp:      ...!{decvax,hplabs,ncar,purdue,rutgers}!gatech!prism!matthew
Internet: [e-mail]

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

Date: 29 Mar 93 23:12:28 GMT
From: Henry Spencer <[e-mail]>
Subject: the call to space (was Re: Clueless Szaboisms )
Newsgroups: sci.space

Organization: U of Toronto Zoology
Lines: 21
Sender: [e-mail]
Source-Info:  Sender is really [e-mail]

In article <1p5rar$[e-mail]> [e-mail] (Pat) writes:
>Also, given that japan has no indigenous sources of radioactives,
>what is the economic difference for japan to import oil,  versus
>radioactives,  of which only a few countries produce...

Vulnerability of the supply line.  Japan could easily stockpile 50 years'
supply of slightly-enriched uranium (which is not useful for bombs, so
acquiring it shouldn't be a major hassle).  This is most impractical for
oil; on a clear day, the captain of a supertanker on the Kuwait-Japan run
can see the funnel smoke from the supertankers ahead of and behind him.

Besides which, if it became a matter of national survival, Japan probably
*could* become self-sufficient in nuclear fuel quickly.  Even granite
contains small amounts of uranium -- indeed, I've seen it mentioned as
a long-term uranium source in scenarios envisioning massive growth of
nuclear power -- and extraction is just a matter of economics, no big
deal if there is no other supplier.  Similarly, mild isotope enrichment
is pretty easy, or you could use natural-uranium reactors like the CANDU.
--
All work is one man's work.             | Henry Spencer @ U of Toronto Zoology
                    - Kipling           |  [e-mail]  utzoo!henry

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

Date: 29 Mar 93 23:18:47 GMT
From: Henry Spencer <[e-mail]>
Subject: the call to space (was Re: Clueless Szaboisms )
Newsgroups: sci.space

In article <1p5ri9$[e-mail]> [e-mail] (Pat) writes:
>|>Please document the ROI for Nuclear Power...
>|Take the cost of WWII to the Japanese, inflate it to current dollars,
>|and you have the de minimus value of a domestically controlled energy
>|source to the Japanese...
> ...
>FDR's embargo of Oil, Tin and Iron  i thought was a combined problem
>for them.

It was the British/US/Dutch oil embargo that was the last straw.  Without
that, they could have toughed it out without renouncing their conquests
in China (the intended result of the embargo).  With it, they had to act
within 6-9 months or see their economy crippled and their military disabled.
They acted.

(Think about this when you hear somebody saying that Saddam could have been
forced to surrender by embargo.)

>I still think it'd be cheaper for them to just buy Texaco.

It's vanishingly unlikely that the US government would permit it.
--
All work is one man's work.             | Henry Spencer @ U of Toronto Zoology
                    - Kipling           |  [e-mail]  utzoo!henry

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

Date: 29 Mar 93 23:27:58 GMT
From: Henry Spencer <[e-mail]>
Subject: the call to space (was Re: Clueless Szaboisms )
Newsgroups: sci.space,talk.politics.space

In article <1ot012$[e-mail]> [e-mail] (Pat) writes:
>I've read alot about SPS's,  they seem like a good idea, etc,  but
>When I talk to my Utility Rep,  their biggest area of investment is
>in Negawatt Producers.  No, that's not a typo.  They make more
>money,  getting people to save energy,  load shift, etc  then they
>make now selling power.

Ask him about the lifetime of his power plants.  They don't last forever.
They're all going to have to be replaced, many of them within our lifetimes.
Reducing load helps, to be sure, but it has limits.
--
All work is one man's work.             | Henry Spencer @ U of Toronto Zoology
                    - Kipling           |  [e-mail]  utzoo!henry

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

Date: 30 Mar 1993 08:35:22 +1000
From: Dan Corbett <[e-mail]>
Subject: US Satellite Crashing on Brisbane??
Newsgroups: sci.space

The newspapers here in Australia are all abuzz with the news that
a US satellite is expected to re-enter and to fall somewhere in
Brisbane, Queensland.  Anybody know anything about this?  Which
satellite?  Is the prediction accurate?  Has it already happened?

Why do you guys always have to throw your space junk at
Australia??  ;^)

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

Date: Mon, 29 Mar 1993 23:03:29 GMT
From: Henry Spencer <[e-mail]>
Subject: Why is Venus so hot?
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Jeremy Follick) writes:
>All of which is, of course, irrelevant in this case. One atm is
>equivalent to 14.7 pounds per square inch. 100 atm is equivalent to
>1470 pounds per square inch. My guess is that you would be squashed
>flat long before you would die of suffocation or Nitrogen Narcosis.

Nonsense.  Pressures inside and outside equalize; your body is not very
compressible.  One atmosphere is a *lot* of pressure, a total of several
tons over the surface of your body.  By Jeremy's reasoning, almost any
substantial pressure change should be fatal.  It's not, as witness both
divers and astronauts.

You do have to worry about making sure that pressures inside and out
*do* equalize.  Quite apart from eardrum problems, any serious internal
overpressure will rupture your lungs -- holding your breath during a scuba
ascent is a potentially-fatal mistake even when the depth looks quite
insignificant.

>Hmm, (a few seconds punching keys on the calculator), 100atm is
>equivalent to diving about 3400 ft underwater (on Earth of course).
>I would be surprised if divers could get down that far without
>a submarine...

I don't believe it has ever actually been done, but I dimly recall a
study which concluded that dives to 5000ft ought to be practical with
hydrogen-oxygen mixes.  (At such pressures, the sheer physical effort
of moving the stuff into and out of your lungs is a serious issue, hence
the desire for the lightest possible gas.  They estimated that helium-
oxygen mixes would become impractical at 3000ft or so.)

As others have observed, most gases are *not* biochemically inert at
such pressures.  In particular, the easily-available ones like nitrogen
and carbon dioxide most definitely are not.  Don't bother looking around
for oddball compounds, either:  even chemically-inert molecules will
typically be excellent anesthetics at such pressures, probably due to
physical effects in cell membranes.  (This is the underlying problem
with nitrogen, in fact -- nitrogen drunkenness is an early stage of
anesthesia.)

To make Venus habitable, we really have to get *rid* of most of the
atmosphere somehow.  It's a hard problem; the old ideas about just
seeding the atmosphere with algae or bacteria were hopelessly naive.
--
All work is one man's work.             | Henry Spencer @ U of Toronto Zoology
                    - Kipling           |  [e-mail]  utzoo!henry

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

End of Space Digest Volume 16 : Issue 388
------------------------------