QUESTION:
What do you want to find about the atmosphere on Mars when you eventually go?

ANSWER from Cathy Davis:
We believe that the atmosphere on Mars was much more Earth-like. That is, it
was thicker and therefore warmer. We would like to know why Mars lost almost
all of its atmosphere. Could this happen to the Earth?

ANSWER from Jim Murphy on February 16, 1997:
Well, what type of data do I hope to receive about the Mars atmosphere?  
Its a long list, but I'll keep it brief here.

I am really, really looking forward to the measurements of surface 
pressure, air temperature near the ground, and wind speed and wind 
direction near the ground that we will receive from the Mars Pathfinder 
lander, scheduled to land on Mars on July 4th of this year.  It will 
certainly be a Happy Fourth of July for me if the spaceship lands safely.
I am a member of the Meteorology science team on Mars Pathfinder.  My 
responsibilities are to determine the wind speed and direction from the 
temperatures of wires which make up the wind measuring sensor.  It is 
sort of like licking your finger and sticking it up in the blowing air:  
the cold side of your finger is the direction from which the wind is 
blowing, and the total 'coldness' imparted to your finger by the wind is 
a measure of the wind speed.  The Pathfinder meteorology data will be 
great in itself, and it will help us to determine how representative was 
the Viking lander 1 meteorology data, which was collected nearby in 
1976-1982, of the weather at in that area on Mars.

From the Mars Global SUrveyor Orbiter, I am looking forward to seeing 
the atmospheric temperatures (from near the surface to heights about 40 
kiolmeters (~24 miles) above the surface.  We can use mathematical 
equations, and some basic atmospheric physics, to relate these 
temperatures to wind speeds and directions (though this is a very 
different process than determining winds than with the Pathfinder wind 
sensor!).   We will be able to compare Mars Global SUrveyor's 
measurements (and inferred winds) with those we calculate in our 
computwer models of the Mars atmosphere.  These models are similar to the 
type of computer models used here on earth for making weather forecsats 
(which we all know can sometimes be terribly wrong).  We hope to learn 
how correct (or incorrect) our models are, and if we find that our models 
are poor at predicting some aspect of martian weather (say that our 
modeled temperatures are always colder than what is observed), than we 
can try to 'fix' our models to improve them, and do better in the future 
at predicting weather on Mars.

I hope you are all able to follow the developments of the Mars 
missions this summer and in to the next school year.   Thanks very much 
for your question, and please don't hesitate to send additional questions 
as you come up with them.

Jim Murphy