InterludeViking mission operations ended in the early 1980s

Viking missions gave scientists the most complete picture of Mars to date. What does this picture look like?

Geologically diverse Dynamic atmosphere (weather) Large scale, global evidence of modification of liquid water in the past.

How long was the water stable?

InterludeAttempts to explore Mars did not start up again until the

early 1990s.

The first one failed.

The next two gave Mars a face-lift and showed a new way to explore.

Modern ExplorationMars Pathfinder “NASA’s Mars Pathfinder mission – the first spacecraft to

land on Mars in more than 20 years and the first ever to send a rover out to independently explore the Martian landscape – is set for touchdown July 4, initiating a new era of scientific exploration that will lead eventually to human expeditions to the red planet.”

Mars Pathfinder Landing Press Kit, July 1997

Modern ExplorationPathfinderThe primary mission objectives were to demonstrate the

feasibility of low-cost landings on, and exploration of, the Martian surface (Faster, Better, Cheaper)

Scientific objectives included atmospheric entry science, long-range and close-up surface imaging; the general objective was to characterize the Martian environment for further exploration

Modern ExplorationPathfinderLaunched December 4, 1996; landed July 4, 1997 in Ares Vallis which was believed to be the site

of an ancient floodLanding site selection made using Viking orbiter imageryFirst rover, first to use airbags

Modern ExplorationPathfinderLander Instruments

Imager for Mars Pathfinder (IMP); the lander was responsible for imaging the rover and relaying data from the rover back to Earth

Meteorological Station

Rover Instruments Three cameras, two stereo cameras in the front and a rear

color imaging system; cameras worked in tandem with a laser system to detect and avoid obstacles

Alpha-Proton-X-Ray Spectrometer (APXS); assess the composition of rocks and soils

Modern ExplorationPathfinder

Modern ExplorationPathfinderNotable results from Pathfinder

More than 16,500 images from the lander and 550 images from the rover

More than 15 chemical analyses of rocks and soil and extensive data on winds and other weather factors

Findings from the investigations carried out by scientific instruments on both the lander and the rover suggest that Mars was at one time in its past warm and wet, with water existing in its liquid state and a thicker atmosphere

Modern ExplorationPathfinderHow did Pathfinder advance scientific understanding of

Mars? Evidence on the ground for a warm, wet past

What technological advance(s) did Pathfinder carry? First rover; can be remotely operated New landing system

ALTAs!!!

Modern ExplorationMars Global Surveyor “The mission will provide a global portrait of Mars as it

exists today…This new view will help planetary scientists to better understand the history of Mars' evolution, and will provide clues about the planet's interior and surface evolution. With this information, we will have a better understanding of the history of all of the inner planets of the solar system, including our home planet, Earth.”

Glenn E. Cunningham, Project Manager

Modern ExplorationGlobal SurveyorObjectives:

High resolution imaging of the surface Study the topography and gravity Study the role of water and dust on the surface and in the

atmosphere Study the weather and climate of Mars Study the composition of the surface and atmosphere Study the existence and evolution of the Martian magnetic field

Modern ExplorationGlobal SurveyorObjectives:

High resolution imaging of the surface Study the topography and gravity Study the role of water and dust on the surface and in the

atmosphere Study the weather and climate of Mars Study the composition of the surface and atmosphere Study the existence and evolution of the Martian magnetic field

Modern ExplorationGlobal SurveyorLaunched November 7, 1996; arrived at Mars on

September 12, 1997 Spent the next 16 months “aerobraking”, began mapping

the surface in March 1997

Modern ExplorationGlobal Surveyor Instruments

Mars Orbiter Camera (MOC); capture high-resolution images of the surface (1.5 meters per pixel)

Thermal Emission Spectrometer (TES); investigate thermal properties of rocks and soils, collect mineralogy data

Mars Orbiter Laser Altimeter (MOLA); elevation data Magnetometer/Electron Reflectometer; search for evidence

of a planetary magnetic field

Modern ExplorationGlobal Surveyor Instruments

Mars Orbiter Camera (MOC); capture high-resolution images of the surface (1.5 meters per pixel)

Thermal Emission Spectrometer (TES); investigate thermal properties of rocks and soils, collect mineralogy data

Mars Orbiter Laser Altimeter (MOLA); elevation data Magnetometer/Electron Reflectometer; search for evidence

of a planetary magnetic field

Modern ExplorationGlobal Surveyor

Modern ExplorationGlobal Surveyor

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Modern ExplorationGlobal Surveyor

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Modern ExplorationGlobal Surveyor

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Modern ExplorationGlobal Surveyor

Credit: Malin Space Science Systems – www.msss.com

Modern ExplorationGlobal Surveyor

Credit: NASA/Goddard Space Flight Center

Modern ExplorationGlobal SurveyorNotable results from Global Surveyor

Mars has a layered crust to depths of 10 km or more. To produce the layers, large amounts of material had to be weathered, transported and deposited.

The northern hemisphere is probably just as cratered as the southern hemisphere, but the craters are mostly buried.

Hundreds of gullies were discovered that were formed from liquid water, possibly in recent times.

Some areas are covered by hematite-rich material. The hematite could have been put in place by liquid water in the past.

The Thermal Emission Spectrometer found that just about all of the surface of Mars is covered with volcanic rock.

Modern ExplorationGlobal SurveyorHow did Global Surveyor advance scientific understanding

of Mars? Smoking gun evidence that liquid water was stable on the

surface for long periods of time Mars exhibits a “global dichotomy” in terms of topography

What technological advance(s) did Global Sureyor carry? Highest-resolution cameras, for the time Laser altimeter TES; lithology, mineralogy