Geology Reference
In-Depth Information
Table 7.1. Selected successful missions to Mars (all NASA expect where indicated otherwise)
Encounter
date
Spacecraft
Mission
Geosciences data
Mariner 4
Jul. 1965
Flyby
Imaging; closest approach 9,912 km
Mariner 6
Jul. 1969
Flyby
Imaging; closest approach 3,330 km
Mariner 7
Aug. 1969 Flyby
Imaging; closest approach 3,518 km
Mariner 9
Nov. 1971 Orbiter
Imaging; ultraviolet and infrared spectrometers; infrared radiometer
Viking 1
Jul. 1976
Lander and
orbiter
Lander imaging; wind speeds, temperatures and directions; chemical
and physical properties of surface; orbiter imaging; gravity;
atmospheric water levels, thermal mapping
Viking 2
Sep. 1976
Lander and
orbiter
Lander imaging; wind speeds, temperatures and directions; chemical
and physical properties of surface; orbiter imaging; gravity;
atmospheric water levels, thermal mapping
Mars Path
nder
Jul. 1997
Lander and
rover
Imaging; surface composition, meteorology
Mars Global
Surveyor
Sep. 1997 Orbiter
Imaging; altimetry; spectroscopy; magnetometer
Mars Odyssey
Oct. 2001 Orbiter
Thermal emission; imaging; gamma-ray spectrometer; radiation
detector
Mars Express
a
Dec. 2003 Orbiter
Imaging; spectroscopy; atmospheric monitoring; radar sounding
Mars
Exploration
Rovers
Spirit
Jan. 2004
Rover
Imaging; spectroscopy; robotic arm; magnets; composition
Opportunity
Jan. 2004
Rover
Imaging; spectroscopy; robotic arm; magnets; composition
Mars
Reconnaissance
Orbiter
Mar. 2006 Orbiter
Imaging; radar sounding; spectroscopy
Phoenix
May 2008
Lander
Imaging; composition; weather, surface properties
a
European Space Agency.
observatory now bearing his name in Flagstaff, Arizona.
Lowell Observatory was originally dedicated to the study
of the Red Planet by mapping its linear features and
following its seasonal changes. Lowell Observatory con-
tinues today to be a key center for planetary studies.
Among the
first geologically oriented observations
were those by Dean McLaughlin, who speculated in
1954 that surface changes indicated vast dust storms and
volcanic eruptions. Today we recognize that dust storms
and other aeolian processes are active today, but the ques-
tion of active volcanism remains open.
During the heyday of the space race, NASA and the
Soviet Union sent numerous spacecraft to Mars. For a
variety of reasons, most of the Soviet missions were
failures, but, as noted earlier, the Soviets engaged in a
highly successful exploration of Venus in the same
period. In contrast, the United States saw successes for
Mars missions in the mid to late 1960s
(Table 7.1)
,
rst
with the Mariner 4
flyby, quickly followed by Mariners
6 and 7. By happenstance, all three
ybys observed the
same heavily cratered part of Mars
(Fig. 7.1)
,leading
much of the scienti
c community to speculate that Mars
was simply another Moon-like object. Fortunately, in the
early 1970s, the Mariner 9 orbiter showed the true diver-
sity of Mars, revealing the huge volcanoes, the tectonic
rift system of Valles Marineris, and the extensive now-
dry river channels. This mission was followed a few
years later (1976) by the Viking Project, which involved
two orbiters and two landers for the
first successful sur-
face operations on Mars. All four spacecraft operated
concurrently, and for many years this was the most
complicated robotic mission to have been
flown in
deep space.
The last of the Viking data were sent to Earth in 1982
from Viking Lander 2. It was 15 years before the next
successful mission to Mars, marked by the landing of
Mars Path
nder in 1997 and the operation of its little
rover, Sojourner. Coupled with the recognition that
some meteorites were blasted from Mars by impacts and
sent on trajectories carrying them to Earth, there was
