Alien Viruses

g1687jkarh at g1687jkarh at
Fri Nov 3 07:06:57 EST 1995

In Article <309902E7.1303 at>
"Gary C. Donaldson" <garyd at> writes:

>With respect to the original question about the survival of
>viruses in space, I have two references which may be of interest.
>Both are from the journal Advances in Space Research, Volume 12,
>Number 4:  Survival rates of some terrestrial microorganisms under
>simulated space conditions (Koike et al., 1991); and Survival in
>extreme dryness and DNA single-strand breaks (Dose et al., 1991).

     Looks interesting. I would like to examine the survivability of various
spores during planetary re-entry. Imagine this: one develops a micro-organism
which is expected to be able to survive on Mars, grow, multiply, and modify 
the environment (such as being photosynthetic, to release oxygen). 
     How would one deposit it on Mars at a minimum of cost ($10K to $10M)?
Maybe by putting it on a HPR/amateur rocket (small, remember bacteria weigh
less than human astronauts), with a small controllable liquid fuel upper stage
(see rec.models.rockets), one could get it most of the way there. For ease
of control the burns will be finished near earth (no long range telemetry and
command issuance) and the rest would be a long coast. 
    But what about the final approach? Drop a few small pellets with their
own heat shielding? What if they miss? A more accurate vehicle would be more
expensive. Why not disperse an "aerosol" (a vacusol?)  of the bacteria in 
space once Mars is nearby and allow the microbes to reenter. Mars has a thin
atmosphere (about 0.01x Earth's atmospheric density) which is just enough to
be equivalent to the Earth's upper atmosphere, the part which cooks meteors 
on re-entry. Pellets or bomblets would cook. However smaller objects, with
their larger surface area/mass ratio gently radiate away excess heat. Under 5
microns no incandescence is generated and at smaller sizes (I heard spores can
be quite small) re-entry could be a very gentle event. An enormous number of
spores could create a very diffuse million mile cloud which would more likely
hit a target as small as Mars (4000 mile diameter) and more colonies could be
generated with one spore packages than could be achieved with larger pellets
or bomblets which due to their size, would be smaller in number for a given 
payload size. 
     A sunscreening carrier would likey be needed, even if the exposure to open 
vacuum was short, and it should be a powerful sunscreen so a submicron layer
would work. 

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