Mars: A Future Home for Humanity chapter three

         MARS NEEDS HUMANS
                                       (c) Robert Zubrin & Chris McKay

         The purpose for sending humans to Mars is not to set altitude
         records for the aviation almanacs. Rather it  is  to  resolve
         some  of  the most important questions concerning the role of
         life in the universe. Evidence available from the Mariner and
         Viking orbiters,  including  photographs  of  dry  riverbeds,
         strongly  indicate  that Mars was once a warm and wet planet,
         and was so for a longer  period  of  time  than  the  several
         hundred  millions  years  it took life to originate on Earth.
         Today Mars is cold  and  arid,  with  a  surface  environment
         hostile  to terrestrial life forms. Nevertheless the question
         remains: since conditions on  Earth  and  Mars  were  similar
         during  the  period  that  life originated on Earth, did life
         also evolve on Mars?

         The answer to this question is fundamental  to  understanding
         humanities place in the Universe. If we find evidence of life
         on Mars, however humble or long extinct, it would tell us the
         origin  of  life  on  Earth was not a result of freak chance.
         Instead, it would confirm our present speculations that  life
         is  a  natural and emergent phenomenon of energy-rich, liquid
         water environments.  It would imply  that  elsewhere  in  the
         galaxy  there  must almost certainly be a spectacular variety
         of other planets with liquid water and with  life,  and  that
         the  universe  we  inhabit is filled with living things whose
         diversity must surpass imagination. We would know we are  not
         alone.

         The  discovery  of  actual  living organisms on Mars could be
         epochal in a practical sense as well. To date,  we  have  had
         only   terrestrial   life   forms   to  study,  all  possibly
         descendants of a common line, so that  our  understanding  of
         biology  is  quite  limited.  Our  position is like that of a
         person who is trying to understand the  nature  of  language,
         but  who  is  only  acquainted with his or her mother tongue.
         Comparing Martian life  forms  with  terrestrial  ones  would
         allow  us  to  begin  to  determine which features of life on
         Earth are incidental and which are fundamental  to  the  true
         nature   of   life  itself.  Such  knowledge  could  lead  to
         astounding  breakthroughs  in  the  biological  sciences  and
         medicine,  resulting  in  dramatic  improvements in the human
         condition.

         The search for evidence of life on Mars will not be  an  easy
         task.   Consider how difficult it is to find fossils on Earth
         of such common megafauna as dinosaurs. Its going to be a  lot
         harder   to   find  fossils  of  microorganisms  tend  to  be
         considerably smaller than dinosaurs and  leave  fossils  that
         are  much  less obvious. For another, the Martian fossils are
         likely to be much older,  and  therefore  rarer.   Since  the
         Martian  environment  is  nowhere  near as well understood as
         that  of  the  Earth,  the  processes  likely  to   lead   to
         preservation are less well known. This will make it harder to
         locate  sites  where  fossils  would  be  preserved  and more
         difficult to understand the unusual settings that resulted in
         preservation.

         On Earth the only way we know how to conduct such searches is
         with  trained  field  scientists.   Trained  not  only   with
         classroom knowledge but with hands-on field experience, often
         over many years. While robotic probes operating from orbit or
         dispersed  landing  sites  can  provide essential preliminary
         data, they are simply incapable of conducting  this  type  of
         exploration of Mars. Consider the probability of success of a
         program  searching for dinosaur fossils on Earth conducted by
         random parachuting down small packages  of  instruments.  The
         result  would  likely  be nil. The same can be said with even
         greater certitude of a purely robotic search for the  remains
         of  life  on  Mars.  If we want to solve the mystery of Mars'
         past or present life, trained field scientists working on the
         planet's surface for many years will be necessary to  do  the
         job.

         In  addition  to  human intelligence and time on the surface,
         the third key element to explore Mars is mobility. Mars is  a
         very big place, with a surface area equal to all Earth's land
         masses  combined.  Sites of scientific interest are likely to
         be far apart. The number of such sites that can be visited by
         a given expedition will increase in proportion to the  square
         of  the sortie range of the available surface transportation.
         Further more, to conduct thorough investigation of a geologic
         feature on Mars will require that studied can be performed at
         sites that span the feature under consideration. For example,
         to determine the timing and cause of fluvial erosion features
         at the terminus of the Valles  Marineris  canyon  system  may
         require that field sites at locations along the entire valley
         system  -  a  distance  of  several  thousand  kilometers- be
         explored.  It may not be necessary to cover this distance  in
         a  single traverse, but the ability to go repeatedly to sites
         and conduct intensive field studies over these  distances  is
         clearly  indicated.   Here  again  we  see  the adoption of a
         "dogsled" approach to Mars exploration  is  essential,  since
         only the production of propellants out of local resources can
         enable  the  use  of high powered ground rovers and ballistic
         flight vehicles  necessary  to  provide  explorers  with  the
         extensive mobility they will need.

         The  top  priority  for  the  first Mars explorers will be to
         resolve the questions concerning the possible  existence  and
         nature of the planet's past or present life. But, however the
         answers  to those questions turn out, over time new questions
         will move to the fore: Will there be life on Mars?  That  is,
         can  humans  settle  Mars?  Can we take a dead or nearly dead
         planet and turn it into a new home for civilization?

         Can we bring the planet to life?