In article <43mitu$…@sdss.fnal.gov> an…@sdss.fnal.gov (James Annis) writes:
>> 12 – "PSYCHIC EXPLORATION" – by Edgar D. Mitchell, Apollo 15 astronaut

Last time I checked, Mitchell flew on Apollo 14.

©THE MISHIN MISSION (Part-3)
Korolyov’s Lunar Mission Profile

        Fredericksburg, Va. – A series of historical interviews conducted
at the June 1991 Paris Air Show have revealed answers to several long
standing questions on the Soviet manned Lunar programs. The Soviet manned
Lunar landing mission sequence profile as developed by General Designer
Acad. S. P. Korolyov, is not quite what has previously been presented
publicly. Acad. Korolyov presented it as a directive to his chief
designers in early 1965, well before his death in January 1966. This
directive finalized the actual manned lunar landing mission sequence. It
also finalized the N1-L3 design which would still have to undergo more
redesign modifications. How much of the mission profile was changed by
the political and ministerial technocratic leadership is unclear. The
exception being that L. Brezhnev, First Secretary of the  CPSU had
ordered that once N1-L3 had flown successfully Acad. Mishin was to fly
the next mission manned irreguardless.
        This mission configuration would remain the same from early 1965
through the early 1970′s. To quote Cosmonaut A. Leonov, "It required and
involved an incredible series of rendezvous." If any one of the early
mission elements failed to be successfully performed as planned it could
have stopped the planned full mission attempt. The manned mission
envisioned a minimum of two separate unmanned Proton/Luna launches that
had to work and two N1-L3 launches. The first N1-L3 was to be unmanned
and the second was to be manned. This was done for safety purposes incase
the manned second launched (LK) Lunar Cabin failed to launch from the
Lunar surface. Prior to this at least two unmanned Proton/Luna’s were to
be despatched to serve as beacons for the L-3, Lunar Cabins landing
guidance targeting. They were also to allow for external inspection of
the unmanned Lunar Cabin (1) by the original design lunar roving
lunokhod. Reinforced by their own observations of what they considered a
risky design and mission format of the American Lunar module, the Soviets
felt that they had to provide a second rescue launch capability for their
cosmonauts. The single cosmonaut could take an EVA Lunar walk or Lunokhod
lunar rover ride to the second Lunar Cabin vehicle which had landed
before the manned lunar landing mission was committed to flight, to
return to Lunar orbit.
        At the time in 1965 the guidance designers felt that they could
guarantee a second vehicles ability to carry out a ballistic landing
within five kilometers of the first vehicle. By 1969 this had been
reduced down to less than 2.5 kilometers. The unmanned and manned Lunar
Cabins were to land inside a five kilometer target ellipse primary
landing zone on fairly flat surface terrain.
        This defined the Lunar Cosmonauts EVA requirements beyond the
planned six hours of EVA in Lunar orbit and on the Lunar Surface. That is
two hours total in Lunar Orbit and Four hours for Lunar Surface
operations with a one and a half hour contengicy built into the time
line. This matches the present seven and a half hour capacity of the
present Orlan EVA spacesuit, used on Mir, with its smaller lighter
backpack. The total design duration capability of the 105 kilogram,  
Kretchet Lunar mission EVA spacesuit for a generic 75 kilogram cosmonaut,
allowed for a minimum of 10 hours to in excess of 12 hours maximum
operation depending on the  rate of use. This was due to the larger
capacity life support oxygen bottle and the systems larger lithium
hydroxide absorber canister within the EVA backpack. It was physically
larger than the present carbon dioxide absorber cannister and the present
oxygen bottle . Work on the Kretchet Lunar suit was started in 1965. Its
design changes reflected the considerable experience gained from the
Voskhod EVA suit.
        Under normal operating conditions the Lunar surface EVA was to be
limited to four hours and an area of only 300-500 meters from the Lunar
Cabin. This further stipulated the Lunar cosmonauts training requirements
to demonstrate a capability to carry out a lunar surface Moon walk EVA of
up to five kilometers distance whether an original design Lunokhod Lunar
rover was available or not. This was a very tough training requirement
included navigating his way to the unmanned Lunar Cabin. A mini rover was
also to be deployed from the Lunar cabin while on the Lunar surface.
        The powered descent from a 110-16 kilometer orbit started at
about 16 kilometers altitude above the Lunar surface utilized a very
steep constant burn Block-D operation requiring less total descent
deceleration velocity than the American powered descent operation. The
Cosmonaut had sight of the landing spot and the first unmanned Lunar
cabin already on the Lunar surface very early on during this powered
descent. However the, Block-D lunar breaking module provided very little
gimbal mounted engine and stationary thruster maneuvering capability. The
final powered descent to the Lunar surface with full maneuvering
capability was carried out by Block-Ye the LK Lunar Cabin in unmanned
automatic control mode or under the Cosmonauts control after separation
from the Block-D between 2.0-1.5 and 0.5 kilometers altitude. This
landing regime provided about twenty five seconds for the final landing.
All Soviet manned lunar landings were restricted to fairly flat lunar
surface conditions and precluded mountainous landings.  In part Mr. Bart
Hendricks article in Spaceflight, "Soviet Lunar Dream That Faded", April
1995, Vol. 37, No. 4, pp. 135-137 is correct except for what is covered
here in.
        The repeatedly observed double countdowns built around N1-L3 and
demonstration countdowns testing and actual flight attempts were infact
both N1-L3 and Proton/Luna countdowns which utilized the same launch
windows that lasted under a week. Often both the N1-L3 ground facilities
systems test vehicle 1M1 and the N1-L3 actual flight test vehicle of
which there were always two were tested in demonstration countdowns. The
purpose of the repeated use of the 1M1 ground test vehicles was to keep
the facilities and launch personnel trained and ready since many of the
conscripts drafted personnel were constantly being changed, and to avoid
problems before anything was carried out with the flight test vehicle.  
The build up to launch of N1-L3 took twenty eight days while the final
countdown took only two days. Whether the mission was to be stretched
over two mouths which is most probable or several days between launches
is unclear as both were in principal possible as long as the vehicles
were preprepared. In affect the Soviet manned Lunar landing mission
profile not merely used Lunar Orbital Rendezvous (LOR), but also used
Lunar Surface Rendezvous (LSR),with multiple independent launches of at
least two unmanned Proton/Luna’s and a unmanned and a later manned
N1-L3/SL-X-15.  
—
_____________________________
Charles P. Vick
Research Analyst
Federation of American Scientists
voice: (202) 675-1025
fax: (202) 675-1024
e-mail: cpv…@fas.org
http://www.fas.org/pub/gen/fas/

[The first attempt to post this yesterday seems to have encountered
a cyberspatial black hole. Apologies in advance if this shows up
on anyone's system twice.]

   The current issue of Aviation Week & Space Technology
(September 18, 1995) has several articles on the military use of
space.  A lot of the material is on DSP, communications satellites
and the like, but there are three items which touch on the use of
reconnaissance satellites to support military operations.
Interestingly (and for me gratifyingly, given my prejudices) the
NRO comes in for criticism in each instance — twice explicitly
and once implicitly.

   The really interesting piece is an essay by two former Space
Command officers,  Michael Coumatos and Dennis Poulos, who
advocate thinking seriously about the implications of fighting
wars in the future.  While they don’t offer specific solutions,
they do ask a lot of the right questions, advocate open discussion
free of Cold War preconceptions and secrecy, and warn, "There
should be a degree of caution regarding over-reliance on
potential ‘black world’ systems to protect or negate space
assets.  The classification and limited scope of these systems
restricts the ability of contingency planners and ‘warfighters’
to develop measures for incorporating such capabilities in
overall combat plans and operational orders."  

   I was also encouraged to see that they recognize the growing
problem of space system vulnerability: "The debate over
vulnerabilities of our space systems must be joined more
aggressively.  As technological advancements in high power
microwaves, lasers, sensors and tracking systems are matched by
increased launch capabilities, U.S. space systems, their ground-
based segments and the interconnecting electronic links are
facing increased levels of risk."   Precisely so.

   In an another article, Col. E. Paul Semmens of the Army Space
Command is quoted as saying about a centralized data
dissemination system of the sort advocated by the NRO, NSA, and
CIA, "Information is power and there are still people out there
who keep data from the guys that need it. We saw it happening at
[the] Roving Sands [exercise], and it was heartbreaking…  I
have a number of NRO requests in — at least 20-25 days old — to
support real wartime contingency planning. And I’m still waiting.
The green door is still closed."

   In a half-page editorial, AWST also calls for faster
dissemination of space-derived information to the troops: "…
intelligence agencies — most born during the Cold War — must
quickly reengineer themselves and demonstrate more relevance to
warfighters.  Information channels should be streamlined and
automated.  Most importantly, access to highly classified space
vehicles and their capabilities should not be confined only to
NRO, CIA and NSA gate-keepers.  Agency officials must discard the
status quo, and work closer with uniformed space command
planners. A good start would be laying all secret projects on the
table."

    If only it were that simple. "Laying all secret projects on
the table" would expose senior NRO managers to extreme
embarrassment, as the secrets conceal not only cases of
spectacular malfeasance in the Reagan-Bush years, but also
continuing inability to cope with changing realities (c.f. the
"reinvestment plan").  Reconnaissance satellite problems aren’t
going to be fixed from inside the IC; it’s going to take
continued pressure from other users — mostly the military — to
get the situation remedied.

[From http://procure.msfc.nasa.gov/]

CBD Issue:9/12/1995

NASA, George C. Marshall Space Flight Center, Procurement Office, Code GP12,
Marshall Space Flight Center, Huntsville, Alabama, [35812], Attn: Space
Flight Operations Restructure

Category 18 — SPACE FLIGHT OPERATIONS CONTRACT SOL RFP 8-SSP-SEB DUE 091495
POC Contact Mr. Walker Lee Evey/GP12, (205) 961-2031 AMENDMENT 2 —
This notice clarifies the synopsis originally published in CBD on August 30,
1995 — This notice provides the applicable acquisition dates per FAR 22.1010,
Notification to Interested Parties Under Collective Bargaining Agreements —
The milestones for this procurement are targeted to be accomplished no sooner
than the following dates: ISSUE DRAFT REQUEST FOR PROPOSAL (RFP) — November
1, 1995; ISSUE RFP — JANUARY 15, 1996; RECEIVE PROPOSALS — March 15, 1996;
START DISCUSSIONS — May 15, 1996; AWARD CONTRACT — August 30, 1996; BEGIN
CONTRACT PERFORMANCE — October 1, 1996 — In addition to this notice, it is
our intent at the current time to also have the individual NASA Contracting
Officers of Shuttle-related contracts affected by this procurement to give
written notification of the forthcoming successor contract and these target
applicable acquisition dates to both the incumbent contractors and the
collective bargaining agents for the contractors’ employees and the
subcontractors’ employees, where appropriate. (0251)

The Triangle Space Society is meeting on Thursday, September 21, at 7:30
P.M. in the Dreyfus Auditorium at the Research Triangle Institute.  The
purpose of the meeting is to plan a TSS display in conjunction with an
event at the N.C. Museum of Life and Science on Saturday, October 28.  Andrew
Chaikin, author of the recent book _A Man on the Moon_, will speak at the
Museum, and TSS plans to set up an exhibit tying in to the Apollo theme.  

TSS welcomes anyone who is interested in this effort to come to the meeting,
or to contact us if you are unable to attend but want to help.  You can
contact me by e-mail, or by phone at 489-9127.  You can also contact
TSS President Steve Nixon in Raleigh at 954-9615.  

Dreyfus Auditorium is inside Dreyfus Laboratory, which is on East Institute
Drive, off Cornwallis Road in the Research Triangle Park.  Feel free to
contact me for more detailed directions.  

                                        Ken kbull…@acpub.duke.edu
                                        TSS Secretary

Dear Sir/Madam,

We refer to the longest solar eclipse on earth on the 24th October 1995 at
Kudat, Sabah,Malaysia.

For more details, you can view our homepage at "http://www.jaring.my/sabah"

RICHARD LUPANG
SABAH TOURISM PROMOTION CORPORATION

The following often requested books are available from the NASA Center
for AeroSpace Information (CASI) or the National Technical Information
Service (NTIS). Both CASI and NTIS use the same document reference
numbers for these books. Note that these are made from microfiche copy;
the reproduction quality is not "as new," but it is acceptable.

    "Chariots for Apollo: A History of Manned Lunar Spacecraft",
    Courtney G. Brooks, James M. Grimwood, Loyd S. Swenson, Jr.,
    NASA SP-4205, Washington DC: USGPO, 1979, 555 pages.
    Notes: CASI/NTIS #N79-28203, US$61.00.

    "Moonport: A History of Apollo Launch Facilities and Operations",
    Charles D. Benson and William Barnaby Faherty, NASA SP-4204,
    Washington DC: USGPO, 1978, 656 pages.
    Notes: CASI/NTIS #N79-12127, US$77.00.

    "On the Shoulders of Titans: The History of Project Gemini",
    Barton C. Hacker and James M. Grimwood, NASA SP-4203,
    Washington DC: USGPO, 1977.
    Notes: CASI/NTIS #N78-20151, US$77.00.

    "Saturn Illustrated Chronology: Saturn’s First Eight Years,
    April 1957 – April 1965", Marshall Space Flight Center,
    Huntsville, AL, NASA TM-X-56798, MHR-4, 1965, 154 pages.
    Notes: CASI/NTIS #65N-33885, US$27.00.

    "Saturn Illustrated Chronology: Saturn’s First Ten Years,
    April 1957 – April 1967", David S. Atkins, Marshall Space
    Flight Center, Huntsville, AL, NASA TM-X-61816, MHR-5,
    August 1968, 208 pages.
    Notes: CASI/NTIS #69N-36686, US$36.50.

    "Stages to Saturn: A Technological History of the Apollo/Saturn
    Launch Vehicles", Roger E. Bilstein, NASA SP-4206, Washington DC:
    USGPO, 1980, 531 pages.
    Notes: CASI/NTIS #N81-29154, US$61.00.
        Abstract from CASI: The origins of the Saturn 1 launch vehicle as a
        test bed and the development of the uprated Saturn B as an interim
        booster for the orbital testing of the first Apollo capsules are
        reviewed in this narrative account of technological advances
        responsible for the AS-506 launch vehicle and the success of the
        Apollo 11 flight. The evolution of the engine, including the
        development of high energy liquid hydrogen engines and of
        insulation for extended storage of cryogenic propellants in vehicle
        tanks are described as well as advances in computer technology for
        the guidance and control systems. Problems encountered in scaling
        components and systems for lunar missions are explored as well
        as political and administrative aspects of the Apollo-Saturn
        project.

    "This New Ocean: A History of Project Mercury",
    Loyd S. Swenson, Jr., James M. Grimwood, Charles C. Alexander,
    NASA SP-4201, Washington DC: USGPO, 1966, 696 pages.
    Notes: CASI/NTIS #N67-14934, US$77.00.

The NASA Center for AeroSpace Information (CASI) is a source
for many out of print NASA documents. US prices includes
the United States, Canada, and Mexico. Foreign prices are
approximately double the US prices. Add US$1.00 per item for
shipping and handling, or US$9.00 per item for shipping and
handling for foreign orders. Call the NASA Access Help Desk to
place orders.

    NASA Access Help Desk
    NASA Center for Aerospace Information
    800 Elkridge Landing Rd.
    Linthicum, MD  21090-2934  USA
    301-621-0390 (voice)
    301-621-0134 (fax)
    h…@sti.nasa.gov (email)

Out of print US Government literature may be obtained from
microfiche copy from the National Technical Information Service
(NTIS). Considering the source media is microfiche, these can be
fairly good quality reproductions. NTIS does not publish a rate
table, but a fair starting guess is US$0.10/page. The NTIS offers
discounts for orders of multiple copies (i.e. 25% for 5 or more).

    National Technical Information Service (NTIS)
    US Department of Commerce
    5285 Port Royal Road
    Springfield, VA 22161
    703-487-4780 (document information)
    703-487-4650 (sales, 8:30AM – 5:00PM EST)

–

THERE"S AN AIRLINE PRICE WAR ON! 7 DAY ADVANCE PURCHASES!
It’s not too late to decide to attend the space conference everyone is
talking about!!!

Space FrontierCon IV-Space: Fiction or Frontier?
Where the America’s real space leader’s and the top writers and producers
of science fiction meet. Come and join those who are revolutionizing our
space program as we discuss what we must do to begin the settlement of the
high frontier!

We are not talking pie in the sky either. From those building the real
rockets that will replace the space shuttle, to NASA astronauts and
officials, to the enterpreneurs who want to Return to the Moon and the
politicians who are rewriting the laws so that we can all someday go too,
this is the real thing. What you hear about at this conference today will
be the news the world hears tomorrow. So join us and join the space
revolution!

———————————————————–

Frontiercon IV Events

Friday

2:00 PM – 4:00 PM Foundation Board Meeting

4:00 PM – 6:00 PM Foundation Advocates Meeting

7:00 PM – 9:00 PM Champagne Reception honoring the spirit of Todd Hawley
and the International Space University he founded
Sponsor:Walt Anderson and Iceberg Transport Inc.

Friday 9:00 pm – Midnight
Party Celebrating the First L-5 Society Conference in LA
Guest of Honor: Jerry Pournelle, Co-Author of "Mote in God’s Eye,"
"Footfall," and Chairman of the Citizen’s Space Advisory Council
All L-5ers past and present are invited to attend.

Saturday  9:00 am – 10:00 am                        
Welcome / Introduction to the Foundation
Speakers:Benigno Muniz – President, California Space Development Council,
Jeff Krukin – Conference Chair, Cong. Jane Harman, Rick Tumlinson –
President, Space Frontier Foundation

Saturday  10:00 am – 12:00 am
Asteroids and  Near Earth Objects – Disasters on the fly or treasures in
the sky?  
Moderator: David Brin, author – "The Uplift War," "Startide Rising"
Speakers: Dr. George Friedman, President – Space Studies Institute, Dr.
John
Lewis – University Of Arizona and author of "Space Resources,"  Tom
Billings
– Institute For Tele-Operated Space Development              

Saturday   12:00 PM – 1:30 PM
Water on the Moon?
Luncheon Update on the Clementine Lunar Mission and the possible discovery
of water on the Moon…                  
Speaker: Col. Pedro Rustan, Director – Clementine Mission

Saturday  1:30 PM – 3:00 PM
Return To The Moon Now!
Moderator: Rick Austin, President – Lion’s Share Inc.(Producers of
Helium 3, The Movie)
Speakers: David Gump, President – Lunacorp, Michael Simon, President –
International Space Enterprises, Dr. Al Binder, Project Director – Lunar
Prospector,

Saturday 3:15pm – 5:00 PM
Cities In The Sky – From Alphatown to Space Colonies
Sponsor: SpaceHab Inc.
Moderator:  Larry Niven, Author, "Ringworld"
Speakers:   Alex Gimarc – Space Frontier Foundation’s "AlphaTown Project,"
Mark Holderman – NASA Johnson Space Center, Chuck Lauer  -  Perigrine
Properties (Space business park developer), Richard Hora, President –
Spacehab Inc.

Saturday 6:00 PM – 7:00 PM
Banquet Reception                          

7:00 PM – 10:00 PM
Awards Banquet
Music provided by the band "UFaux."
Keynote Speaker: Cong. Dana Rohrbacher
Awards will be given to:
"Vision to Reality" – DoD’s Clementine Lunar Mission – For successfully
mapping the Moon using innovative and low cost technologies and
management.
Presenter: Col. Pete Conrad (Apollo 12 Commander), DC-X Flight Manager
Recipient(s): Col. Pedro Rustan – Clementine Lunar Mission, Dr. Stu
Nozette,
Dr. Eugene Shoemaker, Col. Pete Worden, Paul Regeon – Naval Research
Laboratory

Special Board Award
Best Depiction of Space
Ron Howard/Todd Hollowell/Micheal Corenblith/Dave Scott for Universal
Studios – "Apollo 13"

Special Board Award
For  their episode "The Explorers" featuring solar sails.
Paramount’s "Deep Space Nine" Television Series
Presenter: Dr. Robert Staehle – JPL Pluto Mission Director and Solar Sail
Pioneer
Recipient – Herman Zimmerman – Chief Production Designer (For all Star
Trek properties, including the last three movies and STNG.)
(Episode writer and producer also to be awarded.)

"Service to the Frontier"
Presenter:TBD
Recipient: Dr. Charles Lurio, for outstanding work promoting cheap access
to
space.

Sunday 9:00 AM – 10:00 AM
Advocate’s Breakfast – Introducing the Foundation’s new "Center for
American
Space Enterprise"
 Speaker:   Jim Muncy – Foundation Co-Founder

Sunday 10:00 AM – 11:00 AM
Mars as a Frontier
Speaker:  Robert Zubrin, Author "Mars Direct," Martin Marietta
Astronautics Co.

Sunday 11:00 AM – 12:00 AM
Space Fiction and Reality on TV
Speaker: Dave Brody, Producer"Inside Space" –  Scifi Channel

Sunday 12:00 PM – 2:00 PM
Luncheon – SpaceLiners, Orbital Hotels and Moon Spas
Speakers: Tom Rogers – The Sophron Foundation, John Spencer – JSS Design
Inc.

Sunday 2:00 PM – 5:00 PM
Cheap Access To Space                                                    
Moderator:     Jerry Pournelle
Speakers:       Gene Austin, Program Director – NASA X-33 Re Useable
Launch
Vehicle Project, Robert Baumgartner-Lockheed Martin, TBD Rep from
Rockwell,
William Gaubatz – McDonnell Douglas, Henry Vanderbilt – Space Access
Society
Poss. – Livingston Holder – Boeing Company, Dr. Peter Diamandis – The
X-Prize

Sunday 5:00 PM – 5:30 PM
Closing Remarks
Rick Tumlinson
Jeff Krukin

Dead Space Puppies Party
7:00 PM – Until….

The Space Frontier Foundation’s fourth Conference is to be held at
the Continental Plaza Hotel in Los Angeles, CA (800-LAX-HOTEL)
from October 6-8, 1995.  

The price, including the champagne reception, 2 exciting Speaker Luncheons
and our "Vision to
Reality Banquet" is $170. (there is a 25% discount for students!)

To register, please send a check payable to:
Space Frontier Foundation
16 First Ave.
Nyack, NY  10960
———————————————————-

David Anderman
Space Activist
916/421-2621

In article 7…@marlo.eagle.ca, Simon Rowland <si…@curtis.eagle.ca> writes:

>    I was thinking about Zubrin’s mars terraforming proposals, involving
> dropping asteroids to vaporize CO2 in the rock. If we detonated a few
> gigaton warheads on the right spot on Phobos, could we bring it down on
> mars? That would *certainly* vaporize the required amount of rock. It
> would work even better if, somehow, we could make it land on one of the
> polar ice caps.

>    Anyone feel like calculating the visual magnitude of the blast from
> Earth?

Hmmm, I hope that there are no other intelligent lifeforms in space
and particulary not on Mars (this includes USING of Mars by somebody
else without originating from it, which would leave no visible traces
of civilization). If I had been on such creature’s place, I would be
VERY unhappy that some primive idiots, that never left even their star
system, detonate equivalent of their "gigatons of TNT", which damages
my well camuflaged base: "Well, it didn’t damage the base to some large
extent (it’s deep enough), but the mars climat will change and also,
those idiots accidently wiped out my "works of art": few pyramids and
a "face", on which my ancestors worked SO hard. Oh, I’m SO angry…
I can’t bear those idiots any more… I think I’ll demolish ther
planet and build a hyper-spatial bypass instead… OK, where are the
crews of the yellow demolition machines?!!! All planet leaves are
cancelled ! ! ! Get the job done at any cost ! ! !"

——————————————————————-

In a nutshell, what I intended to say, was: don’t mess with
nature, at least not until you have sufficient understanding of
what are you doing.

Arie Kazachin.

Forwarded from the SKEPTIC list:

Although this may be somewhat outside our current sphere of debate, it
does somewhat illustrate a failure of the logic processes in the examination
of a problem.

In discussing techno-war:

>Attacking the mother country is *not* a viable strategy for a secessionist
>colony, unless we make grossly unrealistic assumptions regarding the
>relative capabilities of colony and homeworld.

Taking the premise that any space colony, whether on another planet or in
an artificial environment would be self supporting (i.e., that attacking
the mother country is not just an involved piece of hari-kari), earth
inhabitants share three disadvantages which make them particularly vulnerable
to even a low-tech attack from space:

1. Gravity – it’s harder getting things away from earth than dropping them
on it. Over 40 years ago, Heinlein wrote about an Earth-Moon war where the
Lunies dropped big rocks on the Earth without much retribution. In any war
where gravity is used as a weapon, Earth loses.

2. Atmosphere – we live here in an unconfined atmosphere. An attacker could
dump tailored bacteria, either over population centers or a type that would
kill off oceanic algae and trees. They could drop dust clouds into the
atmosphere from pulverized asteroids and watch our solar constant drop and
the earth freeze. They could direct a large EMP to wreck 90% of our
electronics. We are sitting ducks all breathing the same air.

3. Space Debris – thousands of tons of stuff hit the atmosphere every day.
We can’t prevent all, or even a fraction of it, mainly for reason #1 above.
Space colonists with some mobility could release beach-ball sized atomics
inconspicuously from far out of earth’s orbit on a path which will eventually
intersect ours. We would not be able to guard against all such objects. In
a war, you can dodge or deflect the big stuff, if you see it coming, but you
can’t watch out for all the small stuff.

It is probably a fact of life that somewhere down the road we will be
splitting into an earth-bound contingent and a space-faring group. The
enormously different conditions in space and on other planets will encourage
human speciation again – either by encouraging adaptations to local
environments that will keep locals reproductively isolated, or by
occasionally wiping out environments (like Earth) where mixing could occur.
It would be enormously interesting and instructive to hear from other
civilizations in space to see how they handled the problem, but as of yet,
we don’t seem to have anyone broadcasting the story – unless, of course,
we aren’t reading our wheat fields right..    ;-)

Tom Faller