Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT_ZIP/spacedig/V16_3/V16NO387.ZIP/V16NO387

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Date: Tue, 30 Mar 93 05:34:50
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V16 #387
To: Space Digest Readers
Precedence: bulk


Space Digest                Tue, 30 Mar 93       Volume 16 : Issue 387

Today's Topics:
 Acceptable metric conversions (was Re: Pioneer Venus Last Findings)
                        Algonquin Space Campus
                     Artificial Gravity (3 msgs)
                 DC-X: Pratt Ships Final Test Engine
                             Dyson motor
                       Living in high pressure
                   Mars Observer Update - 03/29/93
                        Mexican Space Program?
                Modulated Directed Tachyons for Commo?
                        More water simulations
                      Question on Cassini Radar
Speculation: the extension of TCP/IP and DNS into large light lag enviroments (2 msgs)
                   Terraforming Venus cheaply? NO!
                             UARS status?
                Venus is covered with water? (2 msgs)

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Date: 29 Mar 93 16:30:26 -0500
From: [e-mail]
Subject: Acceptable metric conversions (was Re: Pioneer Venus Last Findings)
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Bill Higgins-- Beam Jockey) writes:
> In article <[e-mail]>, [e-mail] (Andrew Folkins) writes:
>> In <[e-mail]> [e-mail] (Ron Baalke) writes:
>>>
>>>EVIDENCE POINTS TO OCEANS, LIGHTNING ON EARLY VENUS
>>>
>>>25 and 75 feet deep (762 and 2286 centimeters).
>>>80 miles (129 kilometers) above Venus' surface, it found evidence for
>>>structures (1-60 miles in size (1.6-96 kilometers).
>>>Pioneer provided data from 80 to 210 miles (129 to 336 kilometers)
>>>kilometers) was more than 10 times denser and 2120 F (1,000 degrees Celsius)
> [lots of similar examples deleted]
>>
>> Maybe we should send the PR crew back to Introductory Physics and teach them
>> about significant digits, or at least take their calculators away...
>
> Andrew, you have pointed out the problem very well.  Now for your
> homework, imagine you are the boss of Public Affairs for a NASA
> center.  Write guidelines, in 300 words or less, which will guarantee
> that your employees will always produce acceptable English-to-metric
> and metric-to-English conversion figures in their press releases.
>
> Bill Higgins, Beam Jockey

Here's one straight from Oc's razor - _Just_ use metric measurements!
Let the public or, better yet, journalists do the conversions. ):-)>
That should clear things up.
Tom Freebairn
_

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

Date: Mon, 29 Mar 93 20:23:57 GMT
From: Michael Roberts <[e-mail]>
Subject: Algonquin Space Campus
Newsgroups: rec.models.rc,rec.models.rockets,rec.pyrotechnics,rec.scouting,sci.aeronautics,sci.astro,sci.geo.meteorology,sci.misc,sci.space,tor.general,york.general

              ALGONQUIN SPACE CAMPUS

Algonquin Space Campus is a space education facility located on the site of
the Algonquin Space Complex, situated on the south shore of Lake Traverse
88 km. west of Pembroke Ontario Canada in the heart of Algonquin Provincial
Park. The Institute for Space and Terrestrial Science (ISTS), an Ontario
Centre of Excellence is currently using this site for education and radio
astronomical research under licence from the National Research Council. One
of the hemisphere's largest radio telescope "dishes" is on-site with other
radio astronomy instruments.

Tranquillity II is the modern 18,000 square foot residence containing 20
carpeted staff and guest suites with ensuite baths, a Health Centre with a
resident nurse, games room, lounge, meeting rooms, satellite TV, Corel
Computer Centre, and tuck shop.  Tranquillity II features a supervised
weight room and bikes for fitness. Basketball and volleyball courts are
nearby. Nature walks are also conducted. The waterfront features superb
swimming, canoeing and a supervised sandy beach. Three lab buildings nearby
complete the Campus with a fascinating program in hands-on space science.

Earth Lab focuses on remote sensing using space and airborne imagery. A
special receiver is available to tune in weather photos during satellite
passes. Space Lab explores human performance in space with various vection
devices, including a wild multi-axis "gyroscope" ride. Space robotics lab
uses special robot arms and TV equipped remote controlled "lunar rovers".
Star Lab explores astrophysics using solar telescopes, lasers and
interferometers. Communication satellites are also investigated.  There are
evening plenaries, star parties, model rocket workshops, contests,
campfires, barbeques nightwalks and other social events.

Terry Dickinson, a leading Canadian astronomer and journalist has described
the Algonquin Space Campus experience as "a perfect balance between
entertainment and education". No qualifications or technical background are
required: just a healthy curiosity and a love of nature.

Algonquin Space Campus offers separate 1 week sessions (Sunday to Saturday)
for high school students, or teachers, or adults from June 6 to September
18. Air travelers can fly into Toronto and meet the Space Campus deluxe
highway coach.

For a free poster/brochure please contact Chris Coggon, ISTS, 4850 Keele
St., North York, Ontario M3J 3K1. Phone [phone] or call toll-free in
the US and Canada: 1-800-563-3115. E-mail: [e-mail]

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

Date: Mon, 29 Mar 1993 19:52:27 GMT
From: Greg Moore <[e-mail]>
Subject: Artificial Gravity
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Nick Szabo) writes:
>[e-mail] (Henry Spencer) writes:
>
>>You've missed a point:  where is the *requirement* for it?
>> [artificial gravity]
>
>You've missed a point: where is the *requirement* for astronauts?
>Most of the astronaut program is justified by "life sciences"
>research, which is predicated on an alleged major need for astronauts
>in the future.
>

    You missed the point.  The original poster asked a question
that involved astronauts.  He did not ask for your personal diatribe.

>
>--
>Nick Szabo                     [e-mail]

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

Date: Mon, 29 Mar 1993 21:04:42 GMT
From: "John S. Neff" <[e-mail]>
Subject: Artificial Gravity
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Greg Moore) writes:
>From: [e-mail] (Greg Moore)
>Subject: Re: Artificial Gravity
>Date: Mon, 29 Mar 1993 19:52:27 GMT
>In article <[e-mail]> [e-mail] (Nick Szabo) writes:
>>[e-mail] (Henry Spencer) writes:
>>
>>>You've missed a point:  where is the *requirement* for it?
>>> [artificial gravity]
>>
>>You've missed a point: where is the *requirement* for astronauts?
>>Most of the astronaut program is justified by "life sciences"
>>research, which is predicated on an alleged major need for astronauts
>>in the future.
>>
>
>    You missed the point.  The original poster asked a question
>that involved astronauts.  He did not ask for your personal diatribe.
>
>>
>>--
>>Nick Szabo                     [e-mail]
>
>
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?

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.


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

Date: 29 Mar 93 23:01:05 GMT
From: Nate Smith <[e-mail]>
Subject: Artificial Gravity
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (John S. Neff) writes:
>
>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.

i heard a good story about this incident from a guy who was working on
some fringe aspect of the Gemini program.  he related that long after
the fated mission was abnormally concluded in the Pacific, one of the
post mortem tasks given to the engineers back in the states. they
analyzed all the computer-generated instructions given to the capsule
over that crazy stretch of no control.  they were told to search for
clues in the data that might help them understand what was malfunctioning
in the onboard computer.  when they examined the telemetry they were
astonished.  after a protracted period of futility, suddenly the thrust
corrections came pouring in right on the money and the capsule was
brought back to a nominal configuration.  they were perplexed because
they could not believe the computer could make those calculations that
fast.  they went back to the astronaut pilot and showed him their charts
and analysis.  the astronaut smiled and said "I know.  I shut it off and
switched over to manual."

- nate
(this must be an old story seen before)

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

Date: 29 Mar 93 23:17:43 GMT
From: "Chris W. Johnson" <[e-mail]>
Subject: DC-X: Pratt Ships Final Test Engine
Newsgroups: sci.space

Page 25 of the March 22nd issue of Aviation Week has a very short
article which provides a little info on the status of the DC-X
project which I thought others might be curious to see. In part it
reads:

"Pratt & Whitney has delivered the last of four modified RL10 rocket
engines for use in McDonnell Douglas' prototype DC-X single-stage
rocket technology vehicle.

"The engines will be integrated in the DC-X on a schedule that
should enable flight demonstrations to begin this summer at White
Sands Missile Range, N.M. During testing, DC-X will be flown up to
altitudes of 30,000 ft., and demonstrate rotation and vertical
landing maneuvers within a 100 ft. touchdown footprint. [....]

"The DC-X's RL10A-5s have been modified for variable throttling,
and are equipped with a new thrust chamber for sea-level operation.
Pratt & Whitney produces other versions of the cryogenic RL10 for
use in General Dynamics' Centaur upper stage, but those engines
are designed only for upper atmosphere operation."


Chris W. Johnson

Internet:   [e-mail]
UUCP:       {husc6|uunet}!cs.utexas.edu!ut-emx!chrisj
CompuServe: >INTERNET:[e-mail]
AppleLink:  [e-mail]@internet#

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

Date: 29 Mar 93 20:45:17 GMT
From: Del Cotter <[e-mail]>
Subject: Dyson motor
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>In article [e-mail], [e-mail] (Del Cotter) writes:
>
>>    0 Asteroid Psyche moved into Venus orbit
>>      Construction of Dyson motor begins
>>
>>  500    Dyson motor in operation
>>
>>13200    Venus spun up to 24 hour day by Dyson motor
>>    Dyson motor dismantled
>
>Interesting... What is a Dyson motor?  I think I know what a Dyson sphere
>is.  It is a solar energy capture/conversion sphere approx. the size of
>earth orbit, right?  This must be another Dyson idea.

The Dyson motor was, I think, first proposed as a means of centrifugally
disassembling Jupiter for the raw materials for a Dyson Sphere.  It is
loosely based on the idea of a squirrel-cage motor.  Windings are laid
down along lines of latitude carrying a current to generate a fixed
quadrupole field.  A pole to pole current generates a toroidal field.

A cloud of electric generators in orbit drive the return current [some
handwaving here] and spiral in as they transfer angular momentum to
Venus.  They are then precessed into antiparallel orbits [more handwaving]
and spiral out.  They then go into solar orbit before returning to a high
parallel orbit [this bit I understand] to spiral down and start the next
cycle.

The energy to spin Venus up from 3e-7 rad/s to 7e-5 rad/s comes to about
3e29 J.  This is assumed to come from Clarke Stations (ie. solar power
stations in solar orbit at ~0.1 AU.  Peak power consumption over the
project is ~1e18 W.

Dyson is far from clear where the angular momentum is coming from.  While
some of it may be coming from the Sun's rotation, I think most of it
would come from Venus' orbit around the Sun.  So in spinning Venus up,
you are moving it closer to the Sun by an immeasurably small amount.

Refs.

M J Fogg "The Terraforming of Venus"
J. Brit. Interplanetary Soc. _40_, pp. 551-564 (1986?)

F J Dyson "The Search for Extraterrestrial Technology"
"Perspectives in Modern Physics" pp. 641-655 (1966)
Interscience Publishers, New York

BTW I see my original article <[e-mail]> on the Fogg paper
has expired.  Could some kind soul mail me a copy?


--
 ',' ' ',','  |                                                  |  ',' ' ',','
   ', ,','    |       Del Cotter       [e-mail]      |    ', ,','
     ','      |                                                  |      ','

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

Date: Mon, 29 Mar 93 17:40:49 EST
From: Tom <[e-mail]>
Subject: Living in high pressure

Callec Dradja sez;
>>How about a 100atm CO2/O2 atmosphere, does CO2 somehow interfere with
>>the uptake of oxygen by the lungs, or is CO2 basically inert much like
>>the N2 part or our atmosphere. If we were to increase the amount of
>>N2 in Earth's atmosphere would we also need to increase the ammount
>>of O2 in order for people to breath normally? I must admit that I know
>>very little about human respiration.

Michael Moroney responds;
>No, the body uses the amount of CO2 in the blood, not the amount of O2
>in the blood to determine the need to breathe.  100 atm CO2 would really
>confuse the body if not kill you outright (CO2 dissolves in water/blood,
>100 atm would make your blood a real cola drink!)

From what I (dimly) remember, co2 is poisonous in amounts greater
than around 3% of the total, for completely different reasons.  Anyone know
more about this?  Seems like it had something to do with the ability of
the lungs to take in oxygen.  So even if you conciously breathe, it doesn't
do any good, or something like that.

-Tommy Mac
-------------------------------------------------------------------------
Tom McWilliams | 517-355-2178 (work) \\     Inhale to the Chief!
[e-mail]  | 336-9591 (hm)\\  Zonker Harris in 1996!
-------------------------------------------------------------------------

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

Date: 29 Mar 93 21:29:06 GMT
From: Steve Derry <[e-mail]>
Subject: Mars Observer Update - 03/29/93
Newsgroups: sci.space,sci.astro,alt.sci.planetary

Pat ([e-mail]) wrote:
: Now what SPace NEws said, is that they are concerned about instrument
: failure while waiting for the Dust to settle.   Is this true?
: Are they really concerned about instrument failure?

Can you give a reference to this?  This sounds interesting and I haven't
heard about this before.

: And if that is the case, could they have planned the mission to avoid the
: dust season?   ALso,  it seems to me, that fuel is a real precious
: resource.  After the mapping is done,  reserve fuel could
: be saved for  orbit changes,  or to improve mapping of the moons phobos
: and deimos.

There are two separate propulsion systems on MO, and they use separate fuel
supplies with different types of fuel.  The more powerful is the bi-propellant
system, which is used for cruise trajectory corrections, orbit insertion, and
transition to the mapping orbit.  The other (mono-propellant) system is used
for attitude control (along with momentum wheels) throughout the mission, and
it is used for orbital trim maneuvers after the mapping orbit is achieved.  I
believe it was also used for TCM-3 because the magnitude of the maneuver was
small.

Once the mapping orbit is achieved, the bi-propellant system will no longer be
used, so there is no point in trying to conserve any of its fuel beyond what
is needed for the transition.  It sounds to me like they are a bit fat on
bi-propellant fuel (it does happen every now and then) because everything has
worked out favorably up to this point, so JPL will take advantage of the extra
fuel to accelerate the transition so that science operation can start sooner.

If you look at MO's cruise configuration vs. the fully operational configura-
tion, it appears that the HGA, solar panels, and instrument booms are
positioned so that they will not be contaminated by the bi-propellant engines
during cruise.  The science configuration has these appendages moved towards
the engines but away from the instruments, so that the instruments fixed on
MO's body will have an unobstructed view of Mars.  I don't think they would
want to fire the bi-propellant engines in this configuration, even if they
had the fuel!

--
Steve Derry
<[e-mail]>

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

Date: 29 Mar 93 22:19:07 GMT
From: Henry Spencer <[e-mail]>
Subject: Mexican Space Program?
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>Is there any info on a mexican space program? Now with the trade agreement will
>there be a space agreement (if not already in effect) between the US, Canada,
>and Mexico?

Extremely unlikely on any substantial scale.  Canada's space budget is tiny
compared to the US's, and Mexico's has got to be smaller yet.  If the US is
putting up most of the money, they're going to want control... and Canada
and Mexico are not going to be interested in putting up money for projects
they have no say in.

Canada is already an associate member of ESA, precisely because there was
no way any US-Canada "partnership" was going to be equitably run.  ESA has
its share of big-country-vs-little-country problems, but overall it has a
much better record.
--
All work is one man's work.             | Henry Spencer @ U of Toronto Zoology
                    - Kipling           |  [e-mail]  utzoo!henry

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

Date: 29 Mar 93 22:11:50 GMT
From: "Ray Swartz (Oh, that guy again" <[e-mail]>
Subject: Modulated Directed Tachyons for Commo?
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Simon E. Booth) writes:
>
>Darn- and I was hoping they could develop the tachyon bomb- the bomb
>that detonates before it was dropped....


    Actually, I've always liked the idea of a neutrino bomb.  It detonates
over a target city...

        ... and nobody notices it.


Raymond L. Swartz Jr. ([e-mail])
================================================================================
I read the newspaper today and was amazed that, in 24 hours, five billion
people could accomplish so little.
================================================================================

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

Date: 29 Mar 1993 21:42:35 GMT
From: Dave McKissock <[e-mail]>
Subject: More water simulations
Newsgroups: sci.space

In a previous article, [e-mail] ("Allen W. Sherzer") says:

>
>I'm not saying that assembly of fred won't work. I am saying that our
>EVA experience isn't enough to say it can be done based only on water
>tank simulations.
>
>Note that saying we don't know if it can be done isn't the same as
>saying it can't be done. Also note that NASA now accepts this as an
>unknown and is scheduling more EVA to see if a problem exists.

I believe the work package #4 position is that we provided
sufficient evidence at the Critical Design Review that our
design meets all of the program requirements, specifically
including the requirement for on-orbit installation and
on-orbit maintenance using EVA. We verified our EVA procedures
using water tank simulations.

As I see it, the EVA community disagrees with you. They say that
based on the water simulations, they can state that EVA
procedures needed to assembly and maintain the WP-4
hardware are do-able.


>> 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?

Sorry, I can't defend the astronaut core. Anybody from JSC want
to tackle this?

>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).


--
<< You shall know the truth, and it shall set you free >>
Quote engraved in the marble wall @ CIA Headquarters
[e-mail]

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

Date: 29 Mar 93 20:44:35 GMT
From: Steve Derry <[e-mail]>
Subject: Question on Cassini Radar
Newsgroups: sci.space

The June 91 issue of Proceedings of the IEEE (vol 79, no 6) has an article
describing the Cassini Titan Radar Mapper.  All details in this posting are
from that article, which was written when Cassini was still scheduled for a
1995 launch.

The baseline Cassini mission calls for 59 orbits of Saturn, 35 of which will
make a close flyby of Titan.  29 of these will approach to within 4000 km,
with 15 of these approaching as low as 950-1100 km.  Each Titan pass will
provide an opportunity for about 32 minutes of radar operation yielding
1.5% coverage of Titan's surface per pass.  Although the article didn't
discuss total coverage for the mission, there will be some overlap of coverage
between passes, so the total coverage will be less than 50%.

The radar itself will operate at 13.8 GHz, using the same 3.66m HGA that is
used for telecom (ala Magellan).  The radar will emit a multi-beam pattern
that allows coverage of both sides of the ground track on a single pass.  The
radar operates in 3 resolution modes (depending on the altitude), with resol-
utions ranging from 400m to 1.6km.  One interesting complication is that the
uncertainties in the spacecraft ephemeris and attitude during the flyby's
lead to some pointing uncertainty during radar operation.  The plan is to
acquire the radar imagery in an unfocused SAR mode, and then do precise geo-
coding with a high-accuracy ephemeris which can be obtained from post-encounter
analysis.

In addition to SAR imaging, the radar will be operated in an altimeter/
scatterometer mode.

--
Steve Derry
<[e-mail]>

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

Date: Mon, 29 Mar 1993 19:36:59 GMT
From: "Phil G. Fraering" <[e-mail]>
Subject: Speculation: the extension of TCP/IP and DNS into large light lag enviroments
Newsgroups: alt.internet.services,sci.space

[e-mail] (Keith Mancus) writes:

>>>What is this COPOUS treaty you speak of?

>[e-mail] (Phil G. Fraering) writes:
>> A treaty that gave space "to all mankind;" literally, it gave _any_ nation

>> on the face of the earth veto power over anything done by anyone up there.
>
>> Go look up the COPOUS treaty and the debate surrounding it before you
>> come back to flame. Please.

>  I was under the impression that the US had not signed this treaty.
>Right or wrong?

Right. I furthermore argue that signing it would not be a good idea,
and that having not signed a bad treaty does not automatically turn
it into a good one (which seems to be what some people are saying).

--
Phil Fraering         |"...drag them, kicking and screaming,
[e-mail]|into the Century of the Fruitbat." - Terry Pratchett,
                       _Reaper Man_

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

Date: 29 Mar 93 22:35:01 GMT
From: Henry Spencer <[e-mail]>
Subject: Speculation: the extension of TCP/IP and DNS into large light lag enviroments
Newsgroups: alt.internet.services,sci.space

In article <[e-mail]> [e-mail] (Greg Nikolic) writes:
>>The Moon, Mars, etc. are "claimed for all mankind".
>
>     They probably said that about the New World, too.

Hell no.  Read your history books.  The New World was claimed by individual
governments and companies, who had pretty firm ideas that their property
belonged to *them* and nobody else.  Wars were fought over it.  The spat
over South America got to be so bad that the Pope was called in to decide
what parts belonged to who.  (By the time disputes over North America got
serious, most of the contenders were filthy heretic Protestants like the
British, so the Pope didn't have much of a say up here.)

And yes, I said "and companies".  If slightly-dim memory serves, when the
(British) government of Canada wanted to expand its country out to what is
now western Canada, it had to buy the rights from the Hudson's Bay Company.
(The HBC had control over all territories draining into Hudson's Bay, by
its original royal charter.  At the time, nobody understood just how vast
that area is.)
--
All work is one man's work.             | Henry Spencer @ U of Toronto Zoology
                    - Kipling           |  [e-mail]  utzoo!henry

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

Date: Mon, 29 Mar 93 19:30:48 GMT
From: Dave Jones <[e-mail]>
Subject: Terraforming Venus cheaply? NO!
Newsgroups: sci.space

Simon E. Booth ([e-mail]) wrote:
> It's somewhat ironic that it would be easier (relatively speaking) to colonize
> planets further out than it would be to attempt colonization of Venus.
>
> (too bad we can't terraform the moon :-) .....)
>

Oh, I don't know.  10^-6 lunar masses of water - say a 20+ km ball of ice -
would give you a nice coating of wet stuff that would last, oh, longer than
humans have been living in cities, I should guess.  That's close enough,
isn't it ?  Of course, 14-day nights might be a problem.....

--
||Nothing can prepare you for the revelation   ||
||that your favorite movie director is a dweeb.||
||---------------------------------------------||
||Dave Jones ([e-mail])--------||

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

Date: 29 Mar 93 22:12:06 GMT
From: Henry Spencer <[e-mail]>
Subject: UARS status?
Newsgroups: sci.space

In article <1p14l3$[e-mail]> [e-mail] (Pat) writes:
>Looks, like there is real money in earthto space power beaming
>for eclipse management.   ANyone know how many sites would be
>needed to protect US DomSats in Geo,sync aand how about the more
>leo  birds,  would you need 6-8 World wide stations.

It wouldn't take that many stations to laser-illuminate the solar arrays
of most of the US-visible Clarke-orbit comsats.  The line of sight is
good (that's why the satellites are there!) and only a small chunk of
Clarke orbit is in shadow at any given time.  People are looking into it.

Trying to illuminate low-orbit satellites from the ground is a lost cause.
They are in shadow nearly half the time, and in view of any given point on
the ground for only a few minutes per orbit.
--
All work is one man's work.             | Henry Spencer @ U of Toronto Zoology
                    - Kipling           |  [e-mail]  utzoo!henry

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

Date: 29 Mar 93 20:48:53 GMT
From: donl mathis <[e-mail]>
Subject: Venus is covered with water?
Newsgroups: sci.space,sci.astro

In article <[e-mail]>, [e-mail] (Joe
Cain) writes:
|> In article <[e-mail]>
[e-mail] (James Thomas Green) writes:
|> >
|> >Noted astrophysicist Jay Leno said on the Friday 3/26 Tonight
|> >Show that Venus is covered with 75 feet of water!
|>
|> Come on now. Anyone who has seen the JPL video based on the Magellan
|> data KNOWS it is covered with scrambled eggs.

Then again, anyone who has seen the Tonight Show knows that so is
Jay Leno.

- donl mathis at Silicon Graphics Computer Systems, Mountain View, CA
[e-mail]

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

Date: 29 Mar 93 22:32:46 GMT
From: Chuck Shotton <[e-mail]>
Subject: Venus is covered with water?
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (donl mathis)
wrote:
>
>
> In article <[e-mail]>, [e-mail] (Joe
> Cain) writes:
> |> In article <[e-mail]>
> [e-mail] (James Thomas Green) writes:
> |> >
> |> >Noted astrophysicist Jay Leno said on the Friday 3/26 Tonight
> |> >Show that Venus is covered with 75 feet of water!
> |>
> |> Come on now. Anyone who has seen the JPL video based on the Magellan
> |> data KNOWS it is covered with scrambled eggs.
>
> Then again, anyone who has seen the Tonight Show knows that so is
> Jay Leno.
>

I think the problem is that Leno confused news reports about discoveries
made by the Pioneer spacecraft in orbit around Venus during its demise last
week.

Here's a quote out of the paper from last week:

    "The Pioneer spacecraft, which had been orbiting Venus for 14 years,
burned up shortly after bursting through the cloud-enshrouded planet's
sizzling atmosphere on Oct. 8, 1992 when it ran out of fuel.

    Its final data show the arid, searingly hot planet once was drenched
with 3.5 times as much water as thought earlier -- enough to cover the
entire surface with between 25 feet to 75 feet of either liquid or
vapor."

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End of Space Digest Volume 16 : Issue 387
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