Why we can't go to Mars (yet)

According to BBC Online:-

President George W Bush will announce proposals next week to send Americans
to Mars

but . . .

unless and until we have robotically established conclusively that there is
or is not life on Mars, we can't put humans on the planet because they will
inevitably bio-contaminate it.

Anyone agree?

In article , R F L Henley wrote:
According to BBC Online:-

President George W Bush will announce proposals next week to send Americans
to Mars

but . . .

unless and until we have robotically established conclusively that there is
or is not life on Mars, we can't put humans on the planet because they will
inevitably bio-contaminate it.
Anyone agree?
Does it really matter that much if we bio-contaminate it ? Bringing life to mars
isn't a bad idea imho.

In article , R F L Henley wrote:
According to BBC Online:-

President George W Bush will announce proposals next week to send Americans
to Mars

but . . .

unless and until we have robotically established conclusively that there is
or is not life on Mars, we can't put humans on the planet because they will
inevitably bio-contaminate it.

Problem: It is, in theory, easy to prove there is life on Mars - you
find some (although doing this is difficult). It's next thing to
impossible to prove there isn't; even if you manage to examine a
statistically significant amount of the surface (and 'a few square
yards' don't really count...) you have to consider the prospects for
life in deep rifts, caverns, that sort of thing. As someone has pointed
out, since we started sending probes to Mars we've discovered two entire
sets of life we didn't think existed on *this* planet...

[I'm idly reminded of the /Mars/ trilogy; the protagonists find some
very scabby lichen at the bottom of a *probably* isolated deep
drillshaft, and can't tell if it's indigenous or introduced by them...
almost certainly the latter, but they just Can't Prove It. Oops.]

--
-Andrew Gray

"R F L Henley" :

According to BBC Online:-

President George W Bush will announce proposals next week to send Americans
to Mars

but . . .

unless and until we have robotically established conclusively that there is
or is not life on Mars, we can't put humans on the planet because they will
inevitably bio-contaminate it.

Anyone agree?

Why would we? You used the term "can't" to state options. Should or should
not? Is a valid question, making a statement that we can not, is not a valid
one.

--
I make public email sent to me! Hydrogen Peroxide Rockets, OpenBeos,
SerialTransfer 3.0, RAMDISK, BoatBuilding, DIY TabletPC. What happened to
the time? http://webhome.idirect.com/~earlcp

R F L Henley wrote:

unless and until we have robotically established conclusively that
there is or is not life on Mars, we can't put humans on the planet
because they will inevitably bio-contaminate it.

Anyone agree?

I disagree. Because it is absolutely impossible ever to establish
conclusively, that there is not life on Mars. Even if you send millions of
rovers and probes, and they dig, drill and examine all they can, you can
never *conclusively* rule out the chance that *somewhere*, where we haven't
looked, there might be a couple of bacteria.

Should human activity on Mars bio-contaminate the surface, it should be no
problem for a trained biologist to spot the difference between terrestrial
microbes and organisms never encountered before.

What if, e.g., Spirit found bacteria in a soil sample, that was, with 100%
certainty, E. Coli? What would the most probable explanation be? That
somehow, E. Coli has evolved independently on both Earth and Mars? Or that
E. Coli has survived unchanged since the formation of the Solar System? Or
that somehow, Spirit became contaminated before Earth departure?

--
Steen Eiler Jørgensen
"Time has resumed its shape. All is as it was before.
Many such journeys are possible. Let me be your gateway."

"Steen Eiler Jørgensen" skrev i en meddelelse
. ..

Should human activity on Mars bio-contaminate the surface, it should be no
problem for a trained biologist to spot the difference between terrestrial
microbes and organisms never encountered before.

Not necessarily. If Terran microorganisms are introduced to Mars, and
some of them survive and actually grow, they will be subject to an enormous
selection pressure. A few decades might change them beyond easy
recognition. Do microorganisms have enough junk DNA, which is not subject
to selection pressure, to establish kinship?
Also, there is the possibility that Earthlife has already been introduced
to Mars, a very long time ago. Imagine a large meteorite strike on Earth;
some of the ejecta somehow reaches Earth escape without being cooked, and
Terran microorganisms survive in hibernation, well protected within the
rock. Then this rock impacts Mars, in such a way that the central parts of
the rock is not cooked. Discovering Mars-life with this particular kinship
to Earthlife would be a considerable scientific find.

Jon Lennart Beck.

"Raven" ro.com wrote in
message ...
"Steen Eiler Jørgensen" skrev i en
meddelelse
. ..

Should human activity on Mars bio-contaminate the surface, it should be
no
problem for a trained biologist to spot the difference between
terrestrial
microbes and organisms never encountered before.

Not necessarily. If Terran microorganisms are introduced to Mars, and
some of them survive and actually grow, they will be subject to an
enormous
selection pressure. A few decades might change them beyond easy
recognition. Do microorganisms have enough junk DNA,

I wish people would stop calling the "non protein coding" part of DNA for
junk.
See e.g. Scientific American, nov 2003 for the latest on this.

which is not subject
to selection pressure, to establish kinship?

hmmm, again I think you are assuming junk here. As it is not (junk), it must
be fair to argue that there is selection pressure on these parts as well.

Also, there is the possibility that Earthlife has already been
introduced
to Mars, a very long time ago.

And hopefully more to come! Ok, lets scan Mars for life, but surely it
shouldn't hold back exploration of the planet.

-Simon

Raven wrote:

Not necessarily. If Terran microorganisms are introduced to Mars,
and some of them survive and actually grow, they will be subject to
an enormous selection pressure. A few decades might change them
beyond easy recognition.

"A few decades" - most certainly. I don't see it as a problem for the first
handful of human missions. Besides, you wouldn't start looking for Martian
life right below the habitation module. You'd probably go hundreds - perhaps
thousands - of meters away from the base. Considering that the Martian
surface is very hostile to organic life (oxidizing agents in soil, strong UV
radiation), the probability for terrestrial germs to blow around in the wind
AND for us to discover these germs is very small.

Also, there is the possibility that Earthlife has already been
introduced to Mars, a very long time ago. Imagine a large meteorite
strike on Earth; some of the ejecta somehow reaches Earth escape
without being cooked, and Terran microorganisms survive in
hibernation, well protected within the rock. Then this rock impacts
Mars, in such a way that the central parts of the rock is not cooked.
Discovering Mars-life with this particular kinship to Earthlife would
be a considerable scientific find.

Absolutely. But I see it this way: If Mars is - or was ever - capable of
sustaining life - and that's what we're trying to figure out - traces of
this life should be present all over the planet. The idea of Mars as overall
frigid and sterile, *apart* from unmistakeable signs, only found in e.g. the
Hellas Basin, that Mars supported life long enough for it to develop, is -
as I see it - extremely improbable. If life ever evolved on Mars, we should
be able to find traces of it over most of the planet.

Of course, if we find only small traces of what could appear to be
terrestrial life brought to Mars billions of years ago, we'd probably find
it only in specific locations.

--
Steen Eiler Jørgensen
"Time has resumed its shape. All is as it was before.
Many such journeys are possible. Let me be your gateway."

"R F L Henley" skrev i en meddelelse
...

unless and until we have robotically established conclusively that there
is or is not life on Mars, we can't put humans on the planet because
they will inevitably bio-contaminate it.

To a degree, I agree. The absence of life on Mars can never be
established conclusively, and certainly not by softlanding a number of
robotic probes. There may be subsurface life in a few locations. But a
rather thorough survey by robotic landers may at least conclude that the
surface and near-surface of Mars is very probably without life. Or find it,
of course.

Jon Lennart Beck.

In article ,
R F L Henley wrote:
According to BBC Online:-

President George W Bush will announce proposals next week to send Americans
to Mars

but . . .

unless and until we have robotically established conclusively that there is
or is not life on Mars, we can't put humans on the planet because they will
inevitably bio-contaminate it.

Anyone agree?


No. But I suspect that the first men going to Mars might
well stay in orbit and direct rovers more quickly; with a
time lag of seconds instead of many minutes, they can do
a lot more.



--
This address is for information only. I do not claim that these views
are those of the Statistics Department or of Purdue University.
Herman Rubin, Department of Statistics, Purdue University
Phone: (765)494-6054 FAX: (765)494-0558