Page 32 - (DK) Eyewitness - Mars

Mapping Mars

In the 1960s and 1970s, the Mariner and Viking missions led to
the first topographic maps of Mars, and in 1997 the success of
Mars Pathfinder furthered spacecraft technology. Later that
year, Mars Global Surveyor provided detailed information on
topography, gravity, and magnetic fields. Global Surveyor is
NASA’s most successful mapping mission. Yet planetary
mapmaking involves more than charting mountains and
canyons. Some scientific instruments used in mapping
also identify minerals and frozen liquids. NASA’s
Mars Odyssey orbiter arrived in 2001 to map the
surface, study minerals, and also look for water—
which instrument readings suggested was there.
Next came the European Space Agency’s Mars
Express orbiter in 2003. While mapping the
South Polar cap, Mars Express confirmed
Odyssey's finds of both water ice and carbon
dioxide ice under the surface.

Mars Global Surveyor

At a height of 240 miles (380 km) Global Surveyor orbited
the poles every two hours, employing three main instruments.
The Mars Orbiter Camera took high-resolution images of
surface features as small as 3 feet (1 m). The Thermal Emission
Spectrometer studied the composition of rock, soil, ice,
atmospheric dust, and clouds. Most important, the Mars Orbiter
Laser Altimeter measured the heights of surface features, which were
used to produce the most accurate Martian topographic map of all.
READYING GLOBAL SURVEYOR
Workers at NASA’s Jet Propulsion
Laboratory prepare Global
Surveyor for transfer to a launch pad
at the Cape Canaveral Air Station.
The spacecraft is already mated to
its booster launch vehicle, at bottom.
After the launch, this booster rocket
will fire and propel the spacecraft on
its journey to the Red Planet. These High-gain
workers will soon place Global antenna
Surveyor in a protective canister for
movement to the pad.
Main engine on
propulsion module

Winglike solar array

GLOBAL SURVEYOR’S COMPONENTS
Surveyor looks like a flying box with
wing-like projections extending from
opposite sides. When fully loaded with
propellant—fuel—the spacecraft
weighed 2,342 lbs (1,060 kg). Most of
Drag flap Scientific Surveyor’s mass lies in the equipment
for flight instrument module containing the spacecraft's
control payload
science payload—electronics and
science instruments. The propulsion
module houses Surveyor’s rocket
engines and propellant tanks.

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