Richard is a retired Montana wheat farmer, who just may be the model for the new movie THE ASTRONAUT FARMER.
"if you build it, we will GO".
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Copyright © 2004 by Richard Thieltges. Published by the Mars Society
with
permission


MIDNIGHT RIDERS:
STRATEGIES FOR
PERPETUATING LIFE IN THE UNIVERSE
by
Richard Thieltges


LONG AND SHORT-TERM THREATS TO LIFE

As far as we know 'for certain', we are the only sentient species in
the universe, on the only living planet. As life-forms ourselves, we
naturally have an interest in perpetuating life. We know that our own solar
system has a finite life-span. Indeed, this is the fate of all suns. We are about
half-way through the life-span of our sun, and at some point, commonly
put at about 5 billion years hence, our sun will run out of nuclear fuel,
and go through a process of expansion, destruction of most of its planets, and
then collapse and explode.

Thus, for the life that has evolved in this solar system to continue to
grow and evolve, some way must ultimately be found to migrate to other
suitable star systems before that point. Mars and all other potential human
habitations in our solar system will be destroyed.

There are other short-term threats to life on our planet. Astronomical
impacts, or other local events such as wars, plagues, or other
ecological catastrophes could destroy some or all of life as we know it before the
technology of space travel is developed.

SEEDING LIFE INTO THE GALAXY-THE SHORT TERM INSURANCE POLICY

The short-term threats to life on our Earth are probably well-know to
all. Since there is at this time no absolute guarantee that life exists
elsewhere, some strategy should be pursued to seed life into the galaxy
in the event of a catastrophe on Earth.

What is hereby proposed is to insert a wide variety of soil, rock, and
waterborne microorganisms and spores into inexpensive canisters, and
fire them directly out into space in all directions away from the sun,
seeding the rest of the galaxy with life.

No attempt would need to be made to aim them at any particular target,
other than to keep them in the plane of the Milky Way galaxy. They would be
dispersed in high numbers with the hope that a small percentage would
encounter a star system with earth-like planets, and that eventually
some
would be captured by such planets and crash on their surface. They
would be constructed in such a way that they would open and release the
microorganisms. The small percentage of these microorganisms and spores
that would be capable of living in the new environment would then commence
to colonize the planet and initiate whatever evolution the new mix would
be capable of producing.

The rationale behind such a seemingly radical proposal is actually very
practical. We will not be going to other star systems very soon, and we
will not arrive there for a very long time. It would be a great advantage to
us if evolution on otherwise lifeless planets had time to progress to the
point of converting carbon dioxide and sulfur atmospheres to oxygen
atmospheres by the time we get there.

There is another more important reason to seed life into the rest of
the universe now. We are in a particular window of time in which such a
technological feat is possible. There is no absolute guarantee that we
will always be such a technologically sophisticated species. Ecological
degradation, world wars, world-wide plagues, or astronomical impacts
could degrade humans' ability to continue to take the slow road to the stars.

In such a case, and if in fact the rest of the universe were empty of
life, and if we were to be the only planet capable of evolving the advanced
civilization necessary to initiate space travel, then the universe
would be forever barren. We owe it to the future of evolution in the cosmos to
insure against this possibility at the earliest possible moment that we can do
so.

The odds that the rest of the universe is barren of life are small.
However, they are not zero. The odds that we will encounter some planetary
catastrophe before we are technologically capable of initiating
conventional space colonization is also quite small. However, once again, those odds
are not zero.

The future is unpredictable. We do not know with certainty what may
occur. There is however, one fact that we do know for certain. It is an
absolute certainty, with odds of 100 per cent, that at some time in the future,
our earth and our solar system will become completely uninhabitable. It is
only reasonable to devote a small fraction of our precious resources to such
an important undertaking.

Ethical Considerations

At first the presumption of this program to seed earth-based life
indiscriminately among the stars may give some pause. However, the
advantages outweigh the disadvantages.

In the case where a planet is barren of life, there should be no
ethical
problems. We will have seeded that planet with our DNA-based
predecessors.
This is what we would have done and will do anyway, as we will
inevitably
bring our plants and animals with us to any planet that we would
contemplate
visiting and colonizing, not to mention the myriad microorganisms
inhabiting
our bodies.

In the case where there might already be life of some kind inhabiting
these
worlds, there are of course other considerations. If there is primitive
life
there, then there will be an interaction between the life forms
originating
from different planets. This normally will result in evolution having
more
variability to work with and thus greater biodiversity and adaptation
in its
resulting biota. Again, this will inevitably happen anyway if we arrive
later.

It is only when we contemplate our capsule landing in another advanced
civilization that an ethical problem arises. Normally a small amount of
an
unfamiliar organism will have little effect on a robust established
population. However, it is possible to contemplate that our earth
organisms
could react unfavorably with advanced life similarly to the importing
of
unfamiliar diseases decimating the New World's populations on earth
after
its discovery.

From a long-term perspective, it may perhaps be preferable to have the
interaction with our biota take place on their world. If there is
another
technological civilization out there, then at some point in the far
future
we will meet (if no catastrophes befall either of us). If either of us
are
carrying potentially incompatible diseases, then this meeting and the
subsequent evolutionary adaptation to them would better proceed as soon
as
possible, and (from our point of view) on their planet, not ours.

Some have suggested encoding or restricting the capsule's decomposition
so
as to warn an advanced civilization of the contents. There will of
course be
much discussion on this important ethical issue.

In short, while there are some questions about the ethics of this
proposal,
the advantages of seeding life into a possibly barren universe outweigh
the
disadvantages. From a purely scientific perspective it probably would
be
interesting to observe and study life on some planets that have evolved
purely on their own track with no outside DNA contamination. However
if
life is as ubiquitous as some think, there would be plenty of such
worlds,
as our capsules would only contact a tiny fraction of available star
systems.

Technology

Because many thousands of capsules should be sent out, this would not
be the
type of expensive rocket launch program we are used to. All we need to
do is
to head straight out from earth with enough speed to escape earth's
gravity
and keep on going out of our solar system.

The payload could be made quite small, as large quantities of inoculum
would
not be required. The canisters could be as small as a few inches in
diameter. The main requirement is that they be able to survive an
atmospheric descent onto a planet's surface without burning up, that
they be
able to disintegrate, and that they have some form of cosmic ray
shielding.

One design would have a mild steel inner casing in which the inoculum
can be
sealed, which would be capable of rusting through. Over this could be
several inches of lead. The lead would be a cosmic ray shielding, and
during
atmospheric entry it would melt and slough off, taking accumulated heat
with
it.

Single stage military rockets should (hopefully) someday be able to be
acquired from war-surplus scrap heaps for pennies on the dollar. These
could
be lifted to the edge of the atmosphere with balloons. Altimeters could
trigger firing at this point, and the rockets would go straight out
into
space. No guidance system should be required other than to ensure
stability.

The design of the rocket could be made simple, inexpensive, and mass
produced. One could even involve amateur rocket societies around the
world,
as this is a widespread hobby, and would generate local interest in and
support for the project. Local clubs and communities could finance
launches
and get to include inoculum samples from their local ecosystems. One
could
also envision this being done in a more sophisticated way, with
guidance
being provided to some targets with more well-researched possibilities
of
success. Many hundreds of capsules could be sent in each launch, and
over
the thousands of years of space flight would disperse quite widely.

One other possible and inexpensive way of launching canisters would be
to
insert them into unsuccessful oil well holes and shoot them out with
high
explosives. There have been many proposals to use various types of
mass
drivers to boost materials into low earth orbit, but currently they are
seen
as impractical for various reasons including trajectory control. In
our
case this would not be so much of a factor.

Bruce Mackenzie has proposed a very intriguing extension to this
project. He
has suggested that we insert the human genome into the genome of a
spore-producing microorganism, and use the very long-lived capabilities
of
spores to carry our genome out and disperse it into the universe.

Chromosomes have only small parts of their DNA strings that actually
carry
active genes of the host organism. In between are long strings of
random
base-pairs that ordinarily do not code for anything. In this proposal,
our
human genome would be inserted into these unused spaces, probably with
novel
starting and ending sequences.

Any advanced civilization discovering these organisms would probably
recognize that they were of off-world origin, and immediately sequence
them.
The specially marked sequences would then be recognized as belonging to
another organism. These advanced civilizations would then hopefully be
motivated to grow out and express this novel genome, with perhaps
interesting results.

The term "Midnight Riders" derives from the timing of the firing near
midnight necessary to ensure that the trajectory would be away from the
sun
and outward into space. The "Riders" would be in for a very long
"Midnight"
journey through the blackness of interstellar space, on their way to an
uncertain but perhaps important future.

LONG-TERM SPACE COLONIZATION STRATEGIES

Most space enthusiasts consider that our ultimate salvation will be
achieved
by developing some form of space colonies or spaceships that will be
sent
off to search for and colonize potential earth-like planets. This is
problematic as an ultimate strategy for several reasons.

The most obvious problem with the spaceship strategy is that even under
the
most ambitious scenario, only a very small percentage of Earth's
population
could ever be accommodated on such a spaceship fleet. This problem is
compounded when one thinks of the vast number of plants and animals
that
would need to be included in each spaceship to successfully populate a
viable, diverse ecosystem on a potentially habitable planet. We are not
just
talking about a Noah's ark-like sampling of a few individuals. We know
that
to maintain a viable population of any small or endangered species,
large
numbers must be maintained in a breeding population to avoid genetic
inbreeding problems. This would also apply to our human population.

Another and even larger problem with this approach is the combination
of the
distance and time required to investigate numbers of potential new
solar
systems. We currently can detect planets through two means. The first
is by
observing a star for wobble, and calculating the size and orbit of
potential
planets that would be required to produce that wobble. This method is
currently only capable of detecting gas-giant planets, and these only
relatively close to their parent star with orbital periods of a
reasonably
short period of observation. This method is probably inherently
incapable of
detecting earthlike planets in the habitation zone of a star.

The second method currently used is the transit method, which observes
a
periodic dimming of the light from a star, and calculates what planet
would
be required to pass between the star and Earth to cause such a periodic
dimming. This can currently be used to detect planets down to several
times
Earth mass. However, it is not capable of any analyses of the
conditions
necessary for life, such as water, an oxygen atmosphere, or a
protective
magnetic field. Of course, another limitation of this method is that it
is
only capable of detecting planets that orbit their star in a plane that
is
perfectly aligned with the Earth.

It is possible that at some point in the future we could develop the
technology to detect Earth-like planets directly, and even analyze them
for
some of the characteristics required for sustaining life in large
numbers.
Indeed, plans are underway to construct such a technology consisting of
a
large linked array of telescopes in space.

However, even with such technology, there would be many unanswered and
unanswerable questions remaining, one of which would be the presence of
a
planetary magnetic field capable of shielding against damaging
high-energy
particles, a necessity for the development of life as we know it.

Thus, even with the help of the advanced technology of the future,
there
would be no real guarantee that any star system we headed for would
ultimately be capable of being colonized. We would therefore need to
plan
for our large colonization spaceship to be capable of very long
multigenerational flights through interstellar distances, searching for
and
investigating perhaps many dozens of potential planets before perhaps
finding one that could support life.
This scenario thus raises the question of the availability of power
sources
to propel, heat and maintain populations through potentially many
centuries
of travel through regions where no significant sunlight is available.

We need to start to think of scenarios in which large sections of the
earth's biota can be transported to distant star systems. One could
conceive
of small moons being colonized, and then somehow used as enormous
spaceships
for a long interstellar cruse. Theoretically the earth itself could be
moved
out of orbit, and transported to a distant star system and re-inserted
into
the orbit of a younger star, although what energy source could
accomplish
this is unknown at present. We would not have to actually find a
replacement
planet, but simply insert the Earth into a similar orbit around the new
star, and get another multi-billion year lease on life.

While these are indeed radical proposals, at some point in our future
we
will be facing extinction of life as we know it in this solar system,
with
the possible exception of a few lucky individuals sent out on
starships. At
that point, all of the remaining beings on this planet will really not
have
much to lose by trying radical proposals. By staying in our Sun's
orbit, our
chances of survival will be zero. At least by attempting to journey to
another nearby sun with large bodies as transport, we will have some
chance
of success.

This chance, however small, should, will, and must be taken, for the
fate of
life continuing to grow and evolve in the universe might just depend on
it.