QUESTION:
How would the Pathfinder mission's cost compare to a human mission producing
a similar amount of scientific knowledge?What would be the individual costs,
like for fuel, oxygen, food, etc?

ANSWER from Steve Wall on July 30, 1997:
It is hard to guess how much a similar mission with humans would cost, since
once humans were there they could do so much more than Pathfinder, but
likely more than $20 billion dollars.

What would be the total cost of a human mission to mars?  What would be the
individual costs, like for fuel, oxygen, food, etc?

ANSWER from Steve Wall on December 11, 1997:
Your question asks for detail beyond what we really know.  A human mission
would surely cost in the tens of billions of dollars.  There have been
several estimates made based on different assumptions of how many people,
for how long, what they would do there, etc.  The exact numbers, and the
individual costs that you mention, depend strongly on the details of the
mission you want to do.

ANSWER from John Connolly on December 16, 1997:
Thanks for the question.  John Connolly here at NASA's Exploration Office in
Houston.

We estimate that the total cost of a HUMAN mission to Mars would be
somewhere between 30 and 40 billion dollars, about half of what it cost to
send humans to the moon back in the 60's and 70's.  It costs less because
everything about sending humans into space was new back then, and today
we're pretty good at launching people into space on a regular basis.

Food or fuel don't really cost all that much -- the real costs are for the
space transportation vehicles like the big boosters that will take you from
the Earth's surface to Low Earth Orbit (LEO), and the propulsion systems
that will boost you from LEO on to Mars.  Those big rockets cost almost
one-half of what the whole mission costs, and everything else (habitats,
landers, rovers, science equipment, space suits, food, power systems,
communication systems, life support systems and all the food, clothes and
toothbrushes the astronauts need) costs the other half.

From that you can see that we're working hard on tryingd to reduce the cost
of space transportation, since it is the highest priced item in the mission.

If you want to leaarn more about NASA's current plans for sending humans to
Mars, check out this web site:

http://www-sn.jsc.nasa.gov/marsref/contents.html

And for cool pictures of what this mission might look like, try:

http://www-sn.jsc.nasa.gov/explore/newfras/images.htm

Keep reaching for the stars,

John Connolly
NASA - Johnson Space Center