Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V16_0/V16NO036.TXT

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Date: Tue, 12 Jan 93 05:00:06
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V16 #036
To: Space Digest Readers
Precedence: bulk


Space Digest                Tue, 12 Jan 93       Volume 16 : Issue 036

Today's Topics:
                Anti-atoms (was Re: Making Antimatter)
                             DCX Testing
                            Delta Clipper
                      fiber optic cable (2 msgs)
                         future space travel
                   Invitation to SETI mailing list
  Let's be more specific (was: Stupid Shut Cost arguements) (2 msgs)
Price of moon-dust (was Re:Cheap Mars Rocks (Re: Moon Dust For Sale))
                    privatly financed space colony
                    Saving an overweight SSTO....
      SNC-Meteorite source (was Re^2: Cheap Mars Rocks) (2 msgs)
                      Surveyor 7 - 25 Years Ago

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

Date: 11 Jan 93 16:08:55 GMT
From: Bill Higgins-- Beam Jockey <[e-mail]>
Subject: Anti-atoms (was Re: Making Antimatter)
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Magnus Olsson) writes:
> In article <[e-mail]> [e-mail] (Bill Higgins-- Beam Jockey) writes:
>> H. Poth and collaborators have done work on
>>antiprotonic atoms, where a negative antiproton orbits a positive
>>nucleus for a short time (it's a nice probe of nuclear physics).
>
> And to clarify a little: "A short time" in this context is very short
> indeed. I don't know the lifetime for an antiproton-proton system, but
> the analogous electron-positron system, the positronium "atom", only
> lives for about a microsecond before the electron and positron
> annihilate each other.

I was vague because I was in a hurry.  Looking at the reference more
carefully (H. Poth, "Antiprotonic, Hyperonic, and Antihydrogen Atoms,"
*Proceedings of the First Workshop on Antimatter Physics at Low
Energy*, Fermilab, 1986-- it may not be the definitive source of
information, but had the advantage of being on the shelf in my
office), I see that Poth says the delay between capture of a p-bar
into an atomic orbit and its annihilation is less than 1E-10 seconds
in most solids and liquids.

> NOTE: I'm *not* dismissing antimatter as an energy source for
> spaceships. I'm only saying that it will take a very long time before
> it becomes even remotely practical.

"A very long time" in this context is more than a few microseconds.
These physicists are so addicted to their jargon!

     O~~*           /_) ' / /   /_/ '  ,   ,  ' ,_  _           \|/
   - ~ -~~~~~~~~~~~/_) / / /   / / / (_) (_) / / / _\~~~~~~~~~~~zap!
 /       \                          (_) (_)                    / | \
 |       |     Bill Higgins   Fermi National Accelerator Laboratory
 \       /     Bitnet:     [e-mail]
   -   -       Internet:  [e-mail]
     ~         SPAN/Hepnet:      43011::HIGGINS

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

Date: Mon, 11 Jan 1993 13:56:07 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: DCX Testing
Newsgroups: sci.space

As promised, here is some data on the DC-X test program. About nine
test flights are planned.

1. Flight series 1 will test:
  * Blended control (automatic flight with ground override)
  * Vertical landing and ground effects
  * Systems performance
  * Qmax: ~10 PSF
  * Altitude: ~600 feet AGL

2. Series 2:
  * Aero performance verification
    - Power-On drag
  * Expand performance envelope
  * RTLS demonstration
  * Qmax: ~60 PSF
  * Altitude: ~5,000 feet AGL

3. Series 3:
  * Rotation maneuver to validate aero model
  * Increasing Q at rotation
  * Reacquisition of GPS
  * Propelland management
  * Qrot: ~20-95 PSF
  * Altitude: 20,000 feet AGL

  Allen
--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "A great man is one who does nothing but leaves        |
|  [e-mail]     |  nothing undone"                                       |
+----------------------103 DAYS TO FIRST FLIGHT OF DCX----------------------+

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

Date: 11 Jan 93 13:59:02 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: Delta Clipper
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Gary Coffman) writes:

>>the DC-Y goals are 20,000 pounds to LEO (10K to polar) with an operational..

>I think we need to be a bit more specific about *which* LEO we are
>talking about.

I disagree. The point is that it decreases cost by one to two orders
of magnitude. If it takes two flights, so what? It's still a hell
of a lot cheaper than anything on the market.

   Allen
--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "A great man is one who does nothing but leaves        |
|  [e-mail]     |  nothing undone"                                       |
+----------------------103 DAYS TO FIRST FLIGHT OF DCX----------------------+

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

Date: Mon, 11 Jan 93 08:43:18 EST
From: John Roberts <[e-mail]>
Subject: fiber optic cable

-From: [e-mail]
-Subject: Fiber optic umbilical
-Date: 4 Jan 93 15:30:14 GMT

-Putting a fiber optic umbilical on a remote sensing platform designed to
-traverse rough terrain seems very odd to me.  Can someone explain to me why
-this was done?  A few things come to mind such as eliminating the weight
-required for a radio and associated power supply.  Also the fiber optic does
-allow for high reliability and high speed data transfer.

-I'm *not* throwing stones at the Dante folks.  I'm just doing some head
-scratching and hoping someone will explain this to me.

Well, one thing for sure - plans for an Earth-Mars fiber optic link
will have to be scrapped. :-)

I can imagine the Dante team trying to straighten out the cable by hand,
and that tiny, heartbreaking "snap" (or maybe they didn't hear anything
at all). Commercial fiber optic cable is great in stationary applications,
but it's too easy to stretch it or bend it beyond the radius of curvature
limits. The people who install our fiber optic links put up warning signs
with a drawing of a hangman's noose, implying what will happen to anybody
who tries to move the equipment. :-)

Does anybody (the phone companies or the military, for instance) use
fiber optic cable that's stiff enough to reduce the risk of breaking?

John Roberts
[e-mail]

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

Date: Mon, 11 Jan 93 16:43:53 GMT
From: Doug Mohney <[e-mail]>
Subject: fiber optic cable
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (John Roberts) writes:

>. Commercial fiber optic cable is great in stationary applications,
>but it's too easy to stretch it or bend it beyond the radius of curvature
>limits. The people who install our fiber optic links put up warning signs
>with a drawing of a hangman's noose, implying what will happen to anybody
>who tries to move the equipment. :-)
>
>Does anybody (the phone companies or the military, for instance) use
>fiber optic cable that's stiff enough to reduce the risk of breaking?

There are at least two missiles (Army/FOG-M, and a Navy project) which use
some sort
of spooling mechanism to pay out "cable" (well, probably not more than a
strand). The Army system is (forgive me pureists) basically a longer range TOW
anti-tank missile, designed to be launched off a trailer dragged behind a
Hummer, and will go against either tanks or helos. The Navy missile is more
interesting because they pay out cable between a fast moving attack plane and
the missile at up to hmm, at least 20 kilometers; Army system is some number
not more than 10K.

However, both Army and Navy don't have to worry about rewinding the cable after
the packages are delivered :-)

Both systems have been demonstrated as feasible/workable/makeable, but I'm not
sure what the current political funding headaches are. It's more a matter of
money & politics rather than technology which is holding up full-scale
production and deployment of both systems.
                    I have talked to Ehud, and lived.
  -- >                  [e-mail]                        < --

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

Date: Mon, 11 Jan 1993 15:07:37 GMT
From: Gary Coffman <ke4zv!gary>
Subject: future space travel
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Nick Janow) writes:
>
>Do you have to have a planet under you just because your parents did?  Let
>your imagination roam...  :)

Indeed we *may* need a planet under us, and a particular one at that, if
the environmental biologists are right about some of the things they're
currently nattering about. Some of them think a particular magnetic field
is important for biological development, not to mention radiation shielding.
They seem to think that a 1 G gravity field is important as well. And on
and on.

We like to think that life is infinitely adaptable, but what it adapts
*into* may not be recognizably human or even terrestrial under extra-
terrestrial conditions. A long term space habitat could clarify the
importance of the various environmental inputs supplied by Earth on
the development and maintainence of human and non-human life.

It's likely that we can artificially duplicate any conditions needed
to maintain human life off Earth indefinitely, but we can't be sure
that we haven't missed some subtle factor until we actually try it.

Gary
--
Gary Coffman KE4ZV          |    You make it,     | gatech!wa4mei!ke4zv!gary
Destructive Testing Systems |    we break it.     | uunet!rsiatl!ke4zv!gary
534 Shannon Way             |    Guaranteed!      | emory!kd4nc!ke4zv!gary
Lawrenceville, GA 30244     |                     | emory!ke4zv![e-mail]

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

Date: 11 Jan 93 14:36:19 GMT
From: Del Cotter <[e-mail]>
Subject: Invitation to SETI mailing list
Newsgroups: sci.space,sci.astro,sci.anthropology,rec.arts.sf.science

The message below is an invitation to join a simulation of a successful
Contact with ExtraTerrestrial Intelligence.  If you are interested in
participating in simSETI, contact Jim Moore at:

                        [e-mail]

Please trim the Newsgroups line as appropriate when posting followups.
---Message follows---

      *******************************************************
      *  CONTACT  X   --  INVITATION for PARTICIPATION  in  *
      *                                                     *
      *                    simSETI                          *
      *                                                     *
      *******************************************************

CONTACT is a national academic conference which brings together some of the
nation's foremost scientists, science fiction writers and artists to
exchange ideas, explore possibilities and stimulate new perspectives about
humanity's future.  Since anthropologists study "alien" cultures and science
fiction writers & artists create them, each group may learn something about
"The Other" from such interaction. Our goal: To encourage serious and
creative inter-disciplinary speculation guided by the principles of science.

Each year we meet at CONTACT to promote the integration of human factors
into space age research and policy, emphasize the interaction of the Arts
and Sciences and their technologies, and develop ethical approaches in
cross-cultural contact, whenever and wherever it occurs.

ABOUT simSETI:  How would Earth respond to a successful SETI (Search for
Extraterrestrial Intelligence)?  There are three approaches to finding out:
conduct a real SETI and see what happens (very accurate, but no room for
mistakes); armchair speculation (accuracy depends on the speculator, with
only persuasiveness to validate the ideas prior to "testing"); or to try to
simulate the event (questionable accuracy, but probably the most "realistic"
we can hope for).

simSETI is a simulated ETI detection event, begun at CONTACT IX in March,
1992 and continued via Internet since then.  In it, an "ET team" has created
an alien and the planet, ecology, and culture to go with it; these ETs have
sent a signal which has been received by an "Earth team" which is trying to
decode, interpret, and respond to the signal.  So far, the Earth team has
largely decoded the first set of signals and concluded that they do indeed
represent a message (apparently containing information about a planetary
system and some elementary math notation, etc).  Additional messages
received within the last month are still being deciphered, and more are
expected in the weeks preceding CONTACT X (copies of these signals are
available by email from the address below).

CONTACT X will be held in Santa Clara, CA, from 26-28 Feb. 1993.  During the
conference we will attempt to interpret the ET signals, what they tell us
and what they tell us about the senders themselves.  We will then try to
formulate a "global policy," respond, and see what happens.   Some people
will be onsite, and the rest will continue to participate via email.

What each of us will really learn from this exercise will depend on our
interests.  For some, simSETI represents a cryptography puzzle; for others,
the challenge lies in re-constructing the ETs based on fragmentary clues
plus general physical, biological, and cultural principles.  It is
impossible to predict whether or not we will learn anything about ourselves
that is directly useful for NASA planners. That is in the nature of a
simulation--if we knew what insights it would provide, there would be no
point in doing it (other than to have fun!).

If you are interested in participating in simSETI, contact Jim Moore at

                        [e-mail]

We especially hope for participation from continents other than North
America.  Because CONTACT is based here and most onsite participants are
American, this simulation of a global event risks missing out a global
perspective.

 ************************************************************************
 *  CONTACT is the brainchild of Jim Funaro (Anthropology Dept.,        *
 *  Cabrillo  College, Aptos CA 95003), with input from many others     *
 *  over the 9 years  it has been going.  You can read about CONTACT    *
 *  in the October 1992 issue of _Omni_ ("How to build an alien", by    *
 *  Keith Ferrell); write to Jim Funaro for more background on CONTACT  *
 *  or for registration information to attend CONTACT X in person (no   *
 *  registration required for email participants).  A newsletter is     *
 *  published four times a year and is available for $15 annually from  *
 *  Greg Barr, CONTACT Newsletter, 1412 Potomac Ave. SE, Washington DC  *
 *  20003-3032.                                                         *
 *                                                                      *
 *  CONTACT consists of:                                                *
 *     SYMPOSIA:  Interdisciplinary forums in which professional        *
 *        scientists, writers and artists present scholarly papers for  *
 *        publication and for discussion with the audience.             *
 *                                                                      *
 *     THE BATESON PROJECT:  A seminar of invited experts each year     *
 *        addresses a selected topic of academic and public interest    *
 *        relating to our future on Earth or in space.                  *
 *                                                                      *
 *     CULTURES OF THE IMAGINATION:  An educational scenario involving  *
 *        world building (physical sciences), creating an appropriate   *
 *        alien ecology and biology (life sciences), culture design     *
 *        (social sciences), and/or cross-cultural contact (sciences,   *
 *        arts, and humanities).                                        *
 *                                                                      *
 *     WORKSHOPS:  Educational mini-courses directed by professionals   *
 *        provide theoretical background and "hands-on" experience in   *
 *        world construction, bioform design, culture building, inter-  *
 *        cultural contact, etc.                                        *
 *                                                                      *
 ************************************************************************


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

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

Date: Mon, 11 Jan 1993 14:05:36 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: Let's be more specific (was: Stupid Shut Cost arguements)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Gary Coffman) writes:

>>Why does this have to wait for Freedom?  We could do that right now.
>>In fact, we'd save money launching Freedom on Energia instead of Shuttle.

>The *redesign* (yet again) of Freedom required for it to be launched
>by Energia would very likely cost more than any launch cost savings
>that might be achieved.

An internal NASA group examining that posibility a year ago came fo the
opposite conclusion. They concluded that assembly costs could be cut
in half if the orbit was changed to 51 degrees and Energia was used.

   Allen
--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "A great man is one who does nothing but leaves        |
|  [e-mail]     |  nothing undone"                                       |
+----------------------103 DAYS TO FIRST FLIGHT OF DCX----------------------+

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

Date: Mon, 11 Jan 1993 15:48:12 GMT
From: Gary Coffman <ke4zv!gary>
Subject: Let's be more specific (was: Stupid Shut Cost arguements)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Edward V. Wright) writes:
>In <[e-mail]> [e-mail] (Jeff Greason ~) writes:
>>1) A thermal protection system, capable of surviving multiple reentries
>>   (many) suitable for reuse.  On previous vehicles, this is ablative and
>>   non reusable, or (on Shuttle), heavy and only marginally reusable.
>
>Nonsense.  The first US ICBM warhead (Atlas) used a nonablative copper
>heat shield.  Copper's too heavy for SSTO, but there are many newer
>refractory metals that would work just fine.  The problem is not that
>there's no TPS available, it' choosing from among several alternatives.

A warhead re-entry vehicle is not a good model for a lander. A warhead
doesn't attempt to do atmospheric braking. It's shaped like a long narrow
cone, or hypersonic bullet. It tries to *penetrate* the atmosphere as rapidly
as possible to avoid interception. It's dwell time is very short and it's
protected mostly by the opaque plasma sheath that forms a boundary between it
and the atmospheric friction. Copper is a very good conductor of heat,
second only to silver, but the passage through the atmosphere is so brief
for a warhead that the heat doesn't have time to migrate deeply into the
vehicle and prematurely cook off the conventional explosive lenses.

A lander presents a blunt surface to the atmosphere and tries to shed
as much velocity as possible by atmospheric braking. The dwell time is very
much longer, and the heat loading much higher. Shuttle designers originally
considered a titanium skin for the Orbiter, but even a metal as refractory
as titanium wasn't up to the job (besides driving up fabrication costs
dramatically), so they chose to use refractory silicates in the form of
tiles. These are very poor conductors of heat, you can place your bare
hand against one side of the tile while playing an oxy-acetylene torch
on the other and not notice a temperature rise. There has been much progress
in artificial ceramic refractory materials since Shuttle was designed, and
better choices are likely available now. Indeed, special refractory blankets
have replaced tiles in certain non-critical areas on Shuttle. But copper, or
any other metal won't do for a lander as opposed to a hypersonic plunger like
a warhead.

Gary
--
Gary Coffman KE4ZV          |    You make it,     | gatech!wa4mei!ke4zv!gary
Destructive Testing Systems |    we break it.     | uunet!rsiatl!ke4zv!gary
534 Shannon Way             |    Guaranteed!      | emory!kd4nc!ke4zv!gary
Lawrenceville, GA 30244     |                     | emory!ke4zv![e-mail]

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

Date: Mon, 11 Jan 1993 11:44:23 CET
From: [e-mail]
Subject: Price of moon-dust (was Re:Cheap Mars Rocks (Re: Moon Dust For Sale))
Newsgroups: sci.space,sci.astro,alt.sci.planetary

So, what is the price for the "moon-dust"?
Say something like the price for a small piece of the Nakhla-Meteorite, and
I *defenitely* buy some stuff...|

What amount of "moon-dust" is thought to be released? A few gramms? Some kilo-
gramms? Is it real "dust" or small (millimeter-sized) fragments?

Greetings
  Herbert

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

Date: Mon, 11 Jan 93 09:08 EDT
From: <[e-mail]>
Subject: privatly financed space colony

Your figures seem fine but I see one problem. If you start saving at 20
you arnt ready to purchase a colony untill your 40. If it takes 10 years
from the time you start purchase untill you can expect delivery ,then the mean a
ge of the colonists will be 55 to 60. The moon may be a great place to spend
your old age and you could maybe live to be a hundred there but this isn't
proven yet. (And source of income) If you want to leverage your buy of a colony
you need a way to payback the morgage. If all your investors go to the moon
they wont have a proven source of income and all of ther planet side job
income will disipear.(accept maybe retirment benifits) And the banks at
least in the US frown on giving loans to anyone whos life expectancey is
shorter than the loan period. I hate playing the bad guy, your ideas have
merit and I will give it personal consideration, but you had beter think
of using a Japanese bank.(They are starting to give 100 year morgages to
families as aposed to individuals.) And youd better think about sending
your kids.
beaufait @cebaf2.cebaf.gov

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

Date: 11 Jan 93 12:33:44 GMT
From: "Herity D." <[e-mail]>
Subject: Saving an overweight SSTO....
Newsgroups: sci.space

[e-mail] (Gregory N. Bond) writes:

>2) The mass overrun is a substantial fraction of payload, or exceeds
>payload.  Then a possibility would be to delete the life support and
>crew cockpit and use the thing unmanned.

Its planned to be unmanned. It may later carry passengers in a special
module, but it doesn't need a crew.
--
-----------------------------------------------------------|"Nothing travels   |
| Dominic Herity,  [e-mail],                      |faster than light, |
|Computer Science Dept, Trinity College, Dublin 2, Ireland.|except possibly bad|
| Tel : [phone] ext 1720 Fax : [phone]       |news"-Douglas Adams|

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

Date: Mon, 11 Jan 1993 11:13:44 CET
From: [e-mail]
Subject: SNC-Meteorite source (was Re^2: Cheap Mars Rocks)
Newsgroups: sci.space,sci.astro,alt.sci.planetary

Nobody knows for sure how the SNC came from Mars to Earth, but some models
have been calculated which show that an impact on Mars could have done the
job. Some scientists even say, all three types of SNC's (Shergottites,
Nakhlites and the single Chassigny) were ejected by the same impact on the
surface of their parent planet (=Mars|?|), and there are some elliptical
craters, one of which may be the source region of the SNC's.

I have to admit, that nobody even knows for sure weather they come from the
red planet, but there are some clues that this is the case: Besides the
Water-and Gas-Analysis, one can show that they have formed in an enviroment
with magnetic field and gravitation, only 1.3Ma ago. Minor planets have not
been active for so long, and have no (or very minor) magnetic and gravitational
fields. Thus, the parent body of the SNC's is thought to be a large planet.
Only Mercury, Venus and Mars have a hard surface mad of rocks: It's not easy
to explain the celestial mechanics how a "Mecury-Meteorite" came to earth, as
it is not easy to explain how a "Venus-Meteorite" survived it's high-speed
flight trough the dense atmosphere of Venus.
You see, it MUST be Mars| What else?

Sure enough, SNC's don't fall on Antarctica more often than on other
continents. But unless you see it fall, Luna- and Mars-Meteorites are hard
to distingush from terrest.rocks. (For example, they have no high-iron
content as all the other (Iron-, Stony-Iron- and Stony-)Meteorites.)
After all, from seven known Shergottites, five come from Antarctica, and none
of the three known Nakhlites has been found in Antarctica. Whereas most of
the Antarctic SNC's are rather small (one large Mars-rock of 18kg has been
found), the non-Antarctic falls are mostly large (18kg Zagami, 40kg Nakhla,
a few kg's Chassigny). So possibly some small non-Antarctic SNC's have
simply not been found in the field.

The meaning of life?
Possibly to find a lare mars-rock in your backyard??? :)

So keep on searching|
  Herbert

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

Date: Mon, 11 Jan 93 16:43:32 GMT
From: Joe Cain <[e-mail]>
Subject: SNC-Meteorite source (was Re^2: Cheap Mars Rocks)
Newsgroups: sci.space,sci.astro,alt.sci.planetary

In article <[e-mail]> <[e-mail]> writes:
>Nobody knows for sure how the SNC came from Mars to Earth,
...
>Sure enough, SNC's don't fall on Antarctica more often than on other
>continents. But unless you see it fall, Luna- and Mars-Meteorites are hard
>to distingush from terrest.rocks.

Why has no one looked in Greenland?

Joseph Cain        [e-mail]
[e-mail]        scri::cain
[phone]        FAX [phone] or -0098

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

Date: 11 Jan 1993 17:27 UT
From: Ron Baalke <[e-mail]>
Subject: Surveyor 7 - 25 Years Ago
Newsgroups: sci.space,sci.astro,alt.sci.planetary,comp.robotics,sci.geo.geology

This is in honor of Surveyor 7, which was launched and landed
on the Moon 25 years ago.
-----------------------------------------------------------------

OFFICE OF PUBLIC INFORMATION
JET PROPULSION LABORATORY, CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA.  TELEPHONE [phone]

Sunday, December 31, 1967

       SURVEYOR VII TO COMBINE DIGGING, CHEMICAL TESTING
                 OF SURFACE OF MOON'S HIGHLANDS

         PASADENA, CALIFORNIA--Surveyor VII will both dig and
analyze the Moon's surface if all goes well next month in the
last and probably most difficult of the United States' series
of lunar surface probes.
         This Surveyor is scheduled to land in the rough south-
west highlands, 18 miles north of Tycho Crater.  The four suc-
cessful Surveyors all have descended in the relatively smooth
equatorial belt designated likely for later Apollo astronaut
landings.
         Scientific investigators of the National Aeronautics
and Space Administration and Caltech's Jet Propulsion Laboratory
hope to satisfy their curiosity about this more formidable area
of the Moon and add to the increasing knowledge of the composi-
tion of the Moon's soil.
         Scientific investigators of the National Aeronautics
and Space Administrations and Caltech's Jet Propulsion Labora-
tory hope to satisfy their curiosity about this more formidable
area of the Moon and add to the increasing knowledge of the
composition of the Moon's soil.
         Surveyor III last April utilized a claw-type digger to
probe the hardness of the lunar surface.  Dr. Ronald F. Scott,
Caltech civil engineering professor and experimenter on the
sampling device, said the digging showed the surface material
was granular and slightly cohesive, not unlike some Earth soil.
         The ASI readings from Surveyors V and VI indicate that
the lunar material analyzed is similar to terrestrial basalts
and basaltic achrondite, Dr. Anthony L. Turkevich, University of
Chicago, principal chemical investigator, reports.  The ASI gold
box enables scientists to correlate Moon components with the
chemical elements as well as Earth and meteoritic rock types.
         Basaltic achrondites form a small percentage of all
meteorites that have been found on Earth.  It seems possible to
scientists that they could be fragments of lunar rock, ejected
by the impact of a meteorites on the Moon, Dr. Scott says.
         Surveyor's digger, or surface sampler, operated by
Floyd Robertson, JPL engineer, and Dr. Scott, will scoop up
soil from below the Moon's surface and spread it for the ASI to
analyze.  The plan calls for the claw to dig as deeply as
possible--18 inches is the maximum--as well as scrape surface
material.
         The claw, on the end of a five-foot aluminum flexing
arm, also will be capable of picking up the analyzer box and
putting it down on excavated dirt anywhere within an area of a
few square feet.  On signal from JPL's Goldstone Station, the
claw will grasp a small knob above the box.  The box is attached
to the spacecraft by a nylon cord.
         The digger arm can be swung out in a 112-degree sweep,
nearly one-third of a circle.  It can be lifted as high as 40
inches, and dropped to break up clods or rocks.  The falling
scoop can exert a pressure of three pounds per square inch.
Surveyor III tests, however, found lunar rocks that withstood
up to several hundred pounds per square inch when squeezed by
the door of the motor-driven digger.
         Dr. Scott's conclusion about the surface where Surveyor
III landed was that it was mostly fine-grained, slightly cohe-
sive soil much like damp sand found on Earth, with some increase
in firmness and density with depth.  However, Surveyor III's
digger got down only seven inches.
         By digging deeper trenches, Dr. Scott believes it will
be possible to obtain more data on the bearing strength of the
lunar soil.  This is done by computing the difference in
electrical motor current required to move the scoop in various
phases of the digging.
         The bearing strength of the Moon in the four Apollo
belt areas has been measured at 3 to 8 pounds per square inch
at a depth of one to two inches.  It is suspected to be stronger
further down.  At any rate, NASA and JPL scientists now feel
there is no need to worry about the ability of any of the four
sites tested thus far to support astronauts.
         The digger's five-inch claw will have two small
U-shaped magnets at its base.  With the aid of the television
camera aboard, investigators will see whether anything sticks
to the magnets.  Previous Surveyor magnet tests indicate only
about 1/4 of one per cent of the Apollo belt soil is magnetic,
perhaps meteoritic iron.
         The January mission is the most sophisticated in the
Surveyor series.  The camera, digger and ASI all are operated
via the same radio channel, hence they cannot be commanded
simultaneously.  Any station in the JPL Deep Space Network can
give command signals to the camera and the ASI, but only
Goldstone will control the digger.  This limits its operation to
about five hours daily, with a like period allowed for taking
pictures of the excavating.
         The first post-landing day will be occupied with photo-
surveying the landing area near Tycho and warming up the alpha
scattering box for its first 20-hour analysis.  The digger will
be deployed on the second day and start scraping and scooping.
         With luck, the scientists hope to make at least two
thorough analyses of moon soil--at the surface and in depth--in
the first two weeks after the arrival of Surveyor VII.
----------------------------------------------------------------
From the "Solar System Log"

Surveyor 7
Launched: 0630 GMT, January 7, 1968
Vehicle: Atlas-Centaur 15 (Atlas No 5903C)
Site: ETR 36A
Spacecraft Mass: 1040kg at launch, 306kg on landing
Destination: Moon
Mission: Soft Landing
Arrival: Landed 010536 GMT, January 10, 1968, at 40.86 degrees S/47 degrees W.
Payload: TV Camera + stereo mirrors
         Alpha-scattering instrument
         Surface sampler
         Footpad magnet
End of Mission: February 21, 1968 (last contact 0024 GMT)
Notes: Seventh successful lunar lander (fifth U.S.)

     The four successful Surveyors satisfied Apollo requirements in
the Moon's equatorial zone, allowing Surveyor 7 to be released for a
scientific mission.  The ejecta blanket emanating from the bright,
fresh ray crater Tycho on the far south was chosen, the rough highland
region dictating a target area only 20 km in diameter instead of the
60 km of the earlier missions.  For this reason, two course corrections
were planned, but the first was so accurate - leaving Surveyor 7 only
2.5 km off target - that no further alteration was necessary.
     The three-legged vehicle touched at 3.8m/sec some 29 km north of
Tycho's rim after a 66 hour 35 minute flight.  The cameras revealed a
rough area covered in blocks but, surprisingly, with fewer crater than
the mare sites; there was a gentle slope of 3 degrees.  No other
spacecraft has landed further from the equator, a planned late Apollo
mission to Tycho never materializing.
     After 20.9 hours on the surface, a pyrotechnic squib was fired on
command from Earth to drop the alpha-scattering instrument to the
surface, but the spectrometer stayed put.  This was fortuitously the
first flight with both a sample arm and a spectrometer, and the scoop
was used to force the recalcitrant device to the ground.  That arm
later picked it up to analyze a rock and then the soil in a 1 cm deep
trench, accumulating 63 hours of data during the first lunar day.  The
main finding was a lower iron content than at the mare sites.
     The scoop was used in 16 surface bearing-strength tests, dug
seven trenches - one 40 cm long and 15 cm deep - and turned over a
rock.  One rock sample was "weighed" by lifting it and recording the
required motor current; a value of 2.4-3.1 g/cc was obtained.  One
rock was fractured, and on several occasions material stuck to the
two magnets mounted on the scoop.
     Some 20,993 pictures were recorded during the first lunar day
and observations continued for 15 hours after sunset at 0606 GMT
on January 25.  Image of the Earth and the Sun's corona out to
50 solar radii were obtained.  Stereo imaging of small areas
was possible by using a 9x24 cm mirror mounted on the antenna mast,
and on January 20 the TV had registered two 1 W lasers aimed at the
lander from observatories in California and Arizona.  This demonstrated
the feasibility of using lasers for communications and measuring the
Earth-Moon distance with great accuracy (this was done later with
laser reflectors left by Apollo and Lunokhod).
     Surveyor 7 was reactivated at 1901 on February 12, 1968, but
the long, cold lunar night had taken its toll and only another 45
200-line pictures were returned before it succumbed on February 21.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Choose a job you love, and
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | you'll never have to work
|_____|/  |_|/       |_____|/                     | a day in your life.

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End of Space Digest Volume 16 : Issue 036
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