JOURNAL
OF
GEOPHYSICAL
RESEARCH,
VOL.
106,
NO.
El0,
PAGE
23,289,
OCTOBER
25,
2001
Introduction
to
the
special
section:
The
Mars
Global
Surveyor
mission
Arden
Albee
Division
of
Geology
and
Planetary
Science,
California
Institute
of
Technology,
Pasadena,
California,
USA
Since
the
launch
of
Mars
Global
Surveyor
(MGS)
in
No-
vember
1996,
it
has
returned
more
information
about
Mars
than
all
previous
missions
combined.
The
scientific
impact
of
MGS
has
been
extraordinary.
In
many
ways
we
now
know
Mars
to
be
a very
different
planet
than
when
MGS
arrived
in
1997.
MGS
has
provided
daily
global
and
high
resolution
images,
a
global
topographic
model
better
than
for
Earth,
a corresponding
gravity
model,
and
a magnetic
field
model,
has
mapped
the
sur-
face
composition,
and
has
monitored
the
atmosphere.
Under-
standing
the
roles
of
surface
water,
ground
ice,
sapping,
channel
formation,
and
aeolian
processes
has
been
greatly
enhanced.
This
special
section
provides
a summary
of
the
results
through
the
first
year
in
the
mapping
orbit
at
Mars.
Cur-
rently,
we
have
completed
the
second
year
in
the
mapping
orbit
and
will
be
continuing
mapping
observations
into
April
2002.
On
behalf
of
all
the
authors
I want
to
acknowledge
the
efforts
of
all
the
individuals
on
the
engineering
and
science
teams
who
have
made
this
issue
possible.
Many
of them
started
in the
early
years
of
Mars
Observer,
returned
for
the
develop-
ment
of
MGS,
and
stayed
on
for
all
the
challenges
of
the
aerobraking
periods;
many
are
still
with
the
mission
or
have
moved
on
to
other
Mars
missions.
A.
Albee,
Division
of
Geology
and
Planetary
Science,
California
Institute
of Technology,
Mail
Code
170-95,
Pasadena,
CA
91125,
USA.
( aalbee
@ cco.
ca tech.
edu
)
(Received
May
1, 2001;
revised
May
9, 2001;
accepted
June
6, 2001.)
Copyright
2001
by
the
American
Geophysical
Union.
Paper
number
2001JE001511.
0148-0227/01/2001JE001511509.00
23,289