Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V15_4/V15NO443.TXT

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Date: Sat, 21 Nov 92 05:01:46
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #443
To: Space Digest Readers
Precedence: bulk


Space Digest                Sat, 21 Nov 92       Volume 15 : Issue 443

Today's Topics:
                      Dyson Sphere's (again???)
                FREE-ENERGY TECHNOLOGY For Spacecraft
                      Galileo Update - 11/20/92
                     Lunar "colony" reality check
               man-rated centrifuge in So. California??
                     Moon Capture Theory (3 msgs)
                     NASA Town Meetings Schedule
                         Obscure Help  Needed
                          Scientific method
                     Shuttle replacement (3 msgs)
                            Solar Sailing
                         Space suit research?
          SSTO Viability (was: Shuttle replacement) (2 msgs)

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

Date: Fri, 20 Nov 1992 17:22:55 GMT
From: "Edward V. Wright" <[e-mail]>
Subject: Dyson Sphere's (again???)
Newsgroups: sci.space

In <wf2gt=[e-mail]> Maulik Harish Shah <[e-mail]> writes:

>    This had probably been discussed (I caught the tail end of a Dyson
>Sphere thread in the backposts). But:
>    How would you detect a dyson sphere? A true dyson sphere (as far as I
>know) would totally enclose the sphere. And, logically, the Material
>that  you would have to make the dyson sphere out of would have to have
>an enormous tensile strength.

Well, Dyson himself did not actually propose a solid sphere, which would
require materials that are not only unavailable but unreasonably strong,
given our understanding of physics.  What he invisioned was a large number
of habitats in orbit about a star which, together, would completely encircle
the star in a ball-of-twine formation.  From a distance, it would look like
a solid shell.

A star enclosed by a Dyson sphere (either Dyson's original or the solid
version, which was invented later by science-fiction writers) would be
invisible at normal wavelengths but would be visible, due to waste heat,
in the far infrared.  To astronomers, a star enclosed by a Dyson sphere
would appear as an infrared supergiant.  Dyson proposed that we look for
such stars as a means of finding extraterrestrial intelligence.

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

Date: Fri, 20 Nov 1992 20:14:37 GMT
From: "Michael C. Matthews" <[e-mail]>
Subject: FREE-ENERGY TECHNOLOGY For Spacecraft
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>
>
>     The technology described in the article copied below could be used to
>power spacecraft, space colonies, etc.:
>
>
>                            FREE-ENERGY TECHNOLOGY
>    [blah, blah, blah...]
>
>                                   Robert E. McElwaine
>                                   B.S., Physics, UW-EC
                                    ^^^^^^^^^^^^^
I think THIS is the REAL KEY to this ARTICLE.  BS physics, indeed.


--
Mike Matthews, ex-Tether Dude +------------->   [e-mail]
"Had the Shuttle on a String"  \_ Now accepting NeXTMail via KlugeNet(TM)!
Lockheed-ESC                  |
Houston, TX                   |          *** WILL HACK FOR FOOD ***

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

Date: Sat, 21 Nov 1992 03:40:35 GMT
From: Ron Baalke <[e-mail]>
Subject: Galileo Update - 11/20/92
Newsgroups: sci.space,sci.astro,alt.sci.planetary

Forwarded from Neal Ausman, Galileo Mission Director

                                 GALILEO
                      MISSION DIRECTOR STATUS REPORT
                               POST-LAUNCH
                          November 12 - 19, 1992

SPACECRAFT

1.  On November 13, the Trajectory Correction Maneuver (TCM-16) was performed
on the spacecraft.  The maneuver used the spacecraft's lateral thrusters to
impart a predicted total delta velocity of 0.89 m/s.  This maneuver was
executed at 1200 bps with the spacecraft pointed approximately 7 degrees off
the Sun.

     The spacecraft's performance throughout the activity was nominal. All
RPM (Retro-Propulsion Module) pressures and temperatures and attitude control
indicators were near predicted levels.  After the lateral burn segment, the
sequence planned pointing correction was executed; the sequence planned spin
correction was not needed.

2.  On November 14, after completion of TCM-16, the Energetic Particle Detector
(EPD) instrument was moved from Sector O (TCM safe position) to Sector 5 and
scanning operation initiated to continue science data collection.  The science
scanning mode continued until November 17 at which time the EPD was moved to
Sector 4 and the motor turned off.  The EPD instrument is continuing to
collect science data in Sector 4.

3.  On November 14 and 15, delta Differenced One-Way range (DOR) passes were
performed over DSS-14/63 (Goldstone/Madrid) and DSS-14/43 (Goldstone/Canberra).
Initial results indicate the four delta DOR passes were successfully performed.

4.  On November 16, a periodic RPM 10-Newton thruster maintenance activity was
performed; 10 of the 12 thrusters were "flushed" during the activity.  The
P-thrusters were not flushed because they were used to perform science turn
(SITURN) activities on the same day.  Spacecraft performance throughout the
activity was normal.

5.  On November 16, the spacecraft performed a 13 degree SITURN.  The purpose
of the SITURN was to maintain the spacecraft within plus or minus 10 degrees
of the sun at the current solar distance.  Real-time commands were also sent to
change the downlink telemetry format back to the Low Rate Science (7.68 kbps)
from the Engineering High Rate 1200bps (automatically selected in the maneuver
PA) to collect a unique near-Earth magnetosphere data.

6.  On November 16, the Earth vector and Earth stars were updated to the
spacecraft's current attitude.  This change implements the attitude maintenance
strategy required in the case of an AACS (Attitude and Articulation Control
Subsystem) POR (Power-On Reset).  If a fault occurs which terminates the
currently executing sequence, the spacecraft will maintain its current
attitude.

7.  On November 17, the Relay Radio Hardware (RRH) oscillators No. 1 and 2
were powered on in preparation for the Probe Mission Sequence Test (MST)
scheduled for November 20, 1992.  Shortly after turn on the oscillator
temperatures increased to expected values.

8.  On November 18, real-time commands were sent to turn the Ultraviolet
Spectrometer (UVS) instrument on, load and readout the UVS memory, and start
the UVS microprocessor.  Three memory readouts of the UVS load were completed
and verified prior to turning the UVS microprocessor on. The instrument was
then configured to a nominal state with the master high voltage disabled,
G-channel selected, and the grating stepping.  The UVS is now properly
configured for the start of EE-9 (Earth-Earth 9 sequence). The UVS
supplemental heater was turned off to complete the activity.

9.  On November 19, real-time commands were sent to increase the telemetry
rate from 7.68 kbps to 28.8 kbps in preparation for the Probe Mission Sequence
Test (MST) on the following day.  Additionally, Delayed Action Commands (DACs)
were sent to turn ranging off and two-way non-coherent (TWNC) on prior to the
MST and reconfigure to ranging on and TWNC off after the MST completes.  These
actions were taken to optimize telecommunications performance during the Probe
MST.

10. The AC/DC bus imbalance measurements exhibited some change. The AC
measurement has ranged from 15DN to 17DN and now reads 15DN (3.5 volts).
The DC measurement has ranged from 134DN (15.7 volts) to 142DN (16.7 volts)
and now reads 142DN (16.7 volts).  These measurement variations are consistent
with the model developed by the AC/DC special anomaly team.

11. The Spacecraft status as of November 19, 1992, is as follows:

       a)  System Power Margin -  80 watts
       b)  Spin Configuration - Dual-Spin
       c)  Spin Rate/Sensor - 3.15rpm/Star Scanner
       d)  Spacecraft Attitude is approximately 6 degree
           off-sun (leading) and 16 degrees off-earth (lagging)
       e)  Downlink telemetry rate/antenna-28.8kbps (coded)/LGA-1
       f)  General Thermal Control - all temperatures within
           acceptable range
       g)  RPM Tank Pressures - all within acceptable range
       h)  Orbiter Science- PWS, PLS, UVS, EPD, MAG, HIC and DDS
           are powered on
       i)  Probe/RRH - RRH oscillators powered on, temperatures
           within acceptable range
       j)  CMD Loss Timer Setting - 264 hours
           Time To Initiation - 260 hours


UPLINK GENERATION/COMMAND REVIEW AND APPROVAL:

1.  The EE-12 Final Profile Design Product was approved by the Project on
November 13.  This sequence covers spacecraft activities from January 20, 1993
to January 23, 1993 and from February 8, 1993 to April 12, 1993.

2.  The EE-11 Preliminary Sequence and Command Generation products were
approved by the Project on November 17.  This sequence covers spacecraft
activities from December 7 to December 28, 1992 including the Earth 2 closest
approach on December 8.

3.  The EE-9 Final Sequence and Command Generation package was approved for
transmission by the Project on November 19, 1992.  This sequence covers
spacecraft activities from November 23, 1992 to December 5, 1992.  The
sequence is scheduled to be sent to the spacecraft on November 21.

GDS (Ground Data Systems):

1.  A second SPC-60 (Madrid Signal Processing Center) Telemetry Data Flow test
was conducted on Monday, November 16.  The test was successful in establishing
a configuration for the Probe checkouts.  This configuration utilized two
Type A TPA's (Telemetry Processing Assemblies) in parallel, one configured to
the 56K full duplex line and one configured to the 224kbps Simplex line, with
Area Routing Assembly (ARA-1) as Prime and ARA-2 as backup.  The only drop-outs
with this configuration were associated with "line hits" and were recoverable
on ARA ODR (Original Data Recording) replays. The test also successfully
demonstrated the configuration to be used to support 134.4 kbps High Rate
science at Earth 2.  As a result of an excellent effort by DSN (Deep Space
Network) and SPC-60 personnel, data dropouts have been minimal this week.


TRAJECTORY

     As of noon Thursday, November 19, 1992, the Galileo Spacecraft trajectory
status was as follows:

    Distance from Earth         14,931,800 km (.10 AU)
    Distance from Sun           161,989,800 km (1.08 AU)
    Heliocentric Speed          118,300 km per hour
    Distance from Jupiter       912,828,500 km
    Round Trip Light Time       1 minute, 38 seconds


SPECIAL TOPIC


1.  As of November 19, 1992, a total of 8684 real-time commands have been
transmitted to Galileo since Launch.  Of these, 3660  were initiated in the
sequence design process and 5024 initiated in the real-time command process.
In the past week, 35 real time commands were transmitted: none were initiated
in the sequence design process and 35 initiated in the real time command
process.  Major command activities this week included commands to reconfigure
the downlink telemetry data rate to 7.68 kbps, turn the UVS instrument on and
configure it for science data collection, turn the UVS supplemental heater off,
switch the telemetry rate to 28.8 kbps, and configure ranging and the TWNC for
the probe MST.

2.  A training rehearsal for the GOPEX experiment operations was successfully
completed November 18th.  The rehearsal was supported by elements of the
Galileo Flight Team (MCT, NAV, and SDT), DSN Ops Team and GOPEX operations
Team at Table Mountain Observatory (TMO) and Kirtland AFB.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Learn to recognize the
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | inconsequential, then
|_____|/  |_|/       |_____|/                     | ignore it.

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

Date: 20 Nov 92 12:04:25 EST
From: Benjamin Cash <[e-mail]>
Subject: Lunar "colony" reality check
Newsgroups: sci.space,alt.sci.planetary

In article <[e-mail]> [e-mail] (Wayne Harvey) writes:
>
>I seem to remember some theory a while back that the moon was actually
>*captured* by Earth at some stage (I think it was about 800 million
>years ago), which also has corollaries in some of the very early

 Just to toss a couple of pennies at this one, I believe that the latest and
best accepted theory on how we got the moon involved a collision between

proto-earth and another proto-planet about the size of Mars (note that this
was emphatically NOT Mars itself) We ran a computer simulation in one of my
geology classes that showed that at the proper angle the collision produced
a cloud of debris that set up in orbit around the earth, in a stable enough
situation that they would stay there instead of crashing back down or flying
away. This explains why the moon and earth have very similar compositions,
are of approximately the same age etc...

I learned this a couple of years ago, so it may be out of date and I may have
forgotten some, but this was definitely seen as much more likely than the
captured, simultaneous formation, or the 'tearing off' theories. Anybody who
is more up-to-date feel free to correct me, and I'll try to hunt down my
notes for that class.

Ben Cash
[e-mail]
Havard University

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

Date: 20 Nov 92 18:22:11 GMT
From: Tom Perrine <[e-mail]>
Subject: man-rated centrifuge in So. California??
Newsgroups: sci.space

I'm posting this query for a friend with no net access, so please respond
via e-mail to [e-mail].

Are there any man-rated centrifuges in Southern California?  My friend is
specifically interested in any near San Diego, although anywhere in the state
would be of interest.

Thanks,
Tom Perrine    [e-mail]

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

Date: Fri, 20 Nov 1992 17:31:46 GMT
From: Martin Connors <[e-mail]>
Subject: Moon Capture Theory
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Tom) writes:
>
> >I seem to remember some theory a while back that the moon was actually
> >*captured* by Earth at some stage (I think it was about 800 million
> >years ago), which also has corollaries in some of the very early
> >human legends.--

There were major developments in thinking on the origin of the Moon in the
1980's. Basically the three time-honored theories of which the above is
one (minus the part about human legends), the other two being co-accretion
and Darwin (Jr)'s tidal ripping out, have found a synthesis in the
possibility that a giant impact in the early solar system ripped part of
Earth's mantle out into an orbit debris ring which then coalesced to form
our Moon, with subsequent tidally-induced orbital evolution eventually
taking it to a larger orbit. This accounts for some of the composition
aspects of the Earth/Moon system (Earth has all the iron) if the Earth's
core had already formed at the time of the impact.

Check this out in Hartmann, W.K., Phillips, R. J., and G. J. Taylor
"Origin of the Moon" published by Lunar and Planetary Inst, Houston in
1986 as the conference proceedings from the Kona meeting where these ideas
came together. Some of the articles are technical - others not too bad in
that respect.

Any very recent edition of a good into textbook (Snow for example) also
will have more details. In short many of the objections you raise in your
original post are very valid and that theory is no longer accepted in its
original form - the 'most accepted' (different from being 'right') theory
at the moment combines it with the other two as described above. In that
way the severe bad points of each are diminished (by synergy!), but there
are still a few things to be ironed out...

Martin Connors         |
Space Research         | [e-mail]  [phone]
University of Alberta  |

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

Date: Fri, 20 Nov 92 16:57:18 GMT
From: Dave Jones <[e-mail]>
Subject: Moon Capture Theory
Newsgroups: sci.space

Tom ([e-mail]) wrote:
>
> >I seem to remember some theory a while back that the moon was actually
> >*captured* by Earth at some stage (I think it was about 800 million
> >years ago), which also has corollaries in some of the very early
> >human legends. That would lead to the assumption that the moon would
>
> This seems a rather shaky theory on first look.  For the Earth to capture
> something the size of the moon, and yet stay in the same orbit, and a
> nearly circular one at that, seems highly unlikely.  I could imagine a
>
> Has anyone heard of a fleshing-out of this theory?  Does it use simulations,
> of is it based just on legends, or what?
>
This is more from that 70's pulp book about the Hollow Moon, NASA's
conspiracy to hide the true nature of the Apollo missions etc. etc.
The book quotes legends as saying 'long ago, before there was a Moon' and
things like that.  Since the Moon was supposed to be a self-propelled
starship. the usual capture issues didn't apply.

800 million years is a bit further into the Dreamtime than most legend
hunters like to go.....

--
||------------------------------------------------------------------------
||Dave Jones ([e-mail])|Eastman Kodak Co. Rochester, NY  |

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

Date: Fri, 20 Nov 1992 18:43:42 GMT
From: James Davis Nicoll <[e-mail]>
Subject: Moon Capture Theory
Newsgroups: sci.space

>>I seem to remember some theory a while back that the moon was actually
>>*captured* by Earth at some stage (I think it was about 800 million
>>years ago), which also has corollaries in some of the very early
>>human legends.

    I  find  it *very* difficult  to believe  that events  800
million  years ago would  have corollaries  in  the myths of  a species
4  orders of magnitude less old, except  perhaps by co-incidence.

                        James  Nicoll

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

Date: Sat, 21 Nov 1992 04:12:03 GMT
From: Ron Baalke <[e-mail]>
Subject: NASA Town Meetings Schedule
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Gregory Aharonian) writes...
>    Here's a list of the remaining NASA Town Meetings around the country.
>I missed the New England because I found out too late (was this stuff ever
>posted to the NET?).
>

Yes, this information was posted to sci.space and sci.space.news a month ago.

>        December 3, 2:00-6:30 pm, Ramo Auditorium, CALTECH, Pasadena

One update, the location for December 3 NASA Town Meeting has been changed to
California State University, Dominquez Hills.

>For more information, call 202-453-3006
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Learn to recognize the
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | inconsequential, then
|_____|/  |_|/       |_____|/                     | ignore it.

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

Date: Fri, 20 Nov 1992 18:29:30 GMT
From: "John S." <[e-mail]>
Subject: Obscure Help  Needed
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (John Thompson Reynolds) writes:
>
>Has anybody out there seen any slide rules for sale?  The closest
>thing I've been able to find is a simple circular slide rule included in a
>"basic navigation kit".
>
>|> In article <[e-mail]> [e-mail] (James Davis Nicoll) writes:
>|>        I still find it hard to believe that I could so completely
>|>    forget a skill I used every day not so  long ago. It's also hard to
>|>    believe no book store seems to stock books on the subject anymore.
>|>    Are there no slide-rule makers left?
>|> --

I'm not sure which part of the above was posted by who, but I may have
one for sale. When I first started studying engineering a few years
back, my father gave me one that I looked at for about 5 minutes out of
curiosity. Then I tossed it onto a shelf and forgot about it. Can't
imagine why anyone would want to go through the trouble of learning to
use it. If I can find it, and my dad doesn't want it, (which I
seriously doubt. I'm pretty sure he's never used one), I guess it's for
sale. I'll look for it.
                                                                             \
==============================================================================>
         ______                 ____________________                         /
           /  __   _  _  _  _  /__   _  _  ___  __   _  _  ___  __   __
       ___/  /_/ _/--/ _/\_/  ___/ _/--/ _/_- _/-' _/--/ _/_- _/-<,_/__>

         [e-mail]     (John Shepherd)    Hughes STX, Lanham, MD

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

Date: Fri, 20 Nov 1992 18:38:27 GMT
From: Henry Spencer <[e-mail]>
Subject: Scientific method
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (John Roberts) writes:
>... for instance, for instance, the Earth-impact model of the formation
>of the moon has risen from obscurity to the "most favored model", with
>(as far as I know) little or no new input of information - it's based on
>mathematical models and old Apollo and Voyager data...

There is no problem testing a new theory quite rigorously using old data,
if you do it carefully.  The trick is simply to get some testable predictions
out of the theory before you look (closely) at the data, and then see if it
checks.  This does get more difficult if the new theory has to be calibrated
using the same data, but sometimes it can still be done.  It is more
satisfying to have prediction precede experiment, because that *guarantees*
that the theory was not custom-cooked to match the results, but having a
theory derived from general principles precisely explain measured phenomena
in detail is a valid test, and often a fairly good one.

Mercury's perihelion shift is considered one of the big early tests of
general relativity, even though the odd behavior of Mercury's perihelion
was known well before GR was developed.

In the case of the lunar-origin models, bear in mind also that "most
favored" is not necessarily synonymous with "completely accepted".  None
of the other major theories can explain the known facts *at all* without
truly drastic special-case assumptions.  It's not hard being the best
runner if all your competitors are in wheelchairs.
--
MS-DOS is the OS/360 of the 1980s.      | Henry Spencer @ U of Toronto Zoology
              -Hal W. Hardenbergh (1985)|  [e-mail]  utzoo!henry

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

Date: Fri, 20 Nov 1992 15:52:02 GMT
From: Brad Whitehurst <[e-mail]>
Subject: Shuttle replacement
Newsgroups: sci.space.shuttle,sci.space

In article <[e-mail]> [e-mail] (Allen W. Sherzer) writes:
...
>Most of the savings are because we are approaching the problem in a different
>way. The old way costs did need to be high because designs where complex
>and always pushed the technology. Keeping it simple (the first rule of good
>engineering), using existing well tested technology, and not pushing
>envelopes reduces costs.
>
>>Hmm, didn't you just say that Congress should just fund the DC-X,Y?
>
>A mis-statement on my part. I ment if Congress properly funds DC-Y. I
>do expect that DC-1 would be built by the private sector.
>
    If you are using well tested current technology, why should
the gov't. pay for any of the craft?  I'll agree that NASA has fumbled
several balls in the arena of routine space tranportation.  One of
its original missions, and the one I hope it returns to is to indeed
"push the envelope".  Do the R&D for NASP; do the R&D (and even
initial construction) for space habitat/labs (I'll leave the question
of Freedom's suitability open); do the lunar/planetary explorations.
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.
--

Brad Whitehurst    |   Aerospace Research Lab
[e-mail] |   We like it hot...and fast.

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

Date: Fri, 20 Nov 1992 18:51:45 GMT
From: Henry Spencer <[e-mail]>
Subject: Shuttle replacement
Newsgroups: sci.space.shuttle,sci.space

In article <[e-mail]> [e-mail] (Brad Whitehurst) writes:
>    If you are using well tested current technology, why should
>the gov't. pay for any of the craft?

The components are mostly well tested.  The combination is not.

>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...

Indeed so.  But the first step to showing profit potential is establishing
that the concept works in practice, and this involves enough up-front
financial risk that the private concerns have not been willing to fund it.
(People have tried.)  Nobody is confident enough in the concept that they
are willing to bet their future plans on it, which means no firm orders
for SSTO launchers... and not even Boeing will build an airliner without
getting at least a few firm orders signed first.
--
MS-DOS is the OS/360 of the 1980s.      | Henry Spencer @ U of Toronto Zoology
              -Hal W. Hardenbergh (1985)|  [e-mail]  utzoo!henry

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

Date: Fri, 20 Nov 1992 19:48:45 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: Shuttle replacement
Newsgroups: sci.space.shuttle,sci.space

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

>    If you are using well tested current technology, why should
>the gov't. pay for any of the craft?...

First of all, this is being done to test the concept. Most (not all) of
the parts exist but they are still being used in a new way. The key is the
parts which don't exist yet and to veryfy the overall concept. Since DC-Y
is an experimental craft then we will have a nice testbed to try new
ideas. For example, after DC-Y flies we can replace the engines with
aerospike engines and see if performance improves.

Second of all it the issue of risk. We are currently in a catch-22: nobody
launches much because costs are too high and costs are too high because
nobody luanches much. SSTO offers the promise of greatly reducing costs
and thereby opening the markets.

  Allen

--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "A great man is one who does nothing but leaves        |
|  [e-mail]     |  nothing undone"                                       |
+----------------------155 DAYS TO FIRST FLIGHT OF DCX----------------------+

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

Date: 20 Nov 92 16:15:35 GMT
From: Bob McGwier <wahoo!n4hy>
Subject: Solar Sailing
Newsgroups: sci.space

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.

Bob McGwier

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

Date: Fri, 20 Nov 1992 18:40:47 GMT
From: "John S." <[e-mail]>
Subject: Space suit research?
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Edward V. Wright) writes:
>
>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).
>
This makes me curious. I'm not at all familiar with space suit design.
I was wondering if they divided the suit into separate sections so that
if, say there was an extreme loss of pressure in one part, the rest
would remain pressurized? If so, how is the suit divided up?

If this has already been discussed here, my apologies for rehashing it.
In that case, could someone possibly email a response?

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

Date: Fri, 20 Nov 1992 17:20:03 GMT
From: "Edward V. Wright" <[e-mail]>
Subject: SSTO Viability (was: Shuttle replacement)
Newsgroups: sci.space.shuttle,sci.space

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

>Hmmm... this gives me an idea. Maybe the way to sell SSTO to Gore is
>to emphasize the non-poluting fuel it uses. Deltas and Titans burn
>nasty stuff which wold cause problems in large quantities.

Actually, the biggest polluter is the Space Shuttle.  (Hydrochloric
acid and other byproducts from those big SRBs.)

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

Date: Fri, 20 Nov 1992 17:11:16 GMT
From: "Edward V. Wright" <[e-mail]>
Subject: SSTO Viability (was: Shuttle replacement)
Newsgroups: sci.space.shuttle,sci.space

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

>We need to do other things as well. There was an article on this in
>a recent issue of Design News and the British newspaper The Guardian
>is also working on an article.

That's good, but the critical articles are the ones that appear
just after the first launch.  There were lots of articles written
about the Space Shuttle in the years before it flew, many of them
by good writers who actually knew what they were talking about it.
But none of them succeeded in mobilizing very much support for the
Space Shuttle.  That didn't happen until the public saw the launch
on television and read the (often inaccurate) front-page articles
from the usual AP wire service hack "science" writers.

Timing is critical.  I know that McDAC isn't spending a lot of money
on advertising and PR, but I hope they're ready with a good press
kit to hand out at the first launch.  Space groups supporting SSTO
should have their own press kits ready also.



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End of Space Digest Volume 15 : Issue 443
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