Interlude  Viking 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?

Interlude  Attempts 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 Exploration Mars 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 Exploration Pathfinder  The 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 Exploration Pathfinder  Launched December 4, 1996; landed July 4, 1997 in Ares Vallis which was believed to be the site of an ancient flood  Landing site selection made using Viking orbiter imagery  First rover, first to use airbags

Modern Exploration Pathfinder  Lander 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 Exploration Pathfinder

 Notable 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 Exploration Pathfinder  How 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 Exploration Mars 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 Exploration Global Surveyor  Objectives:  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 Exploration Global Surveyor  Objectives:  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 Exploration Global Surveyor  Launched November 7, 1996; arrived at Mars on September 12, 1997  Spent the next 16 months “aerobraking”, began mapping the surface in March 1997

Modern Exploration Global 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 Exploration Global 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 Exploration Global Surveyor

Credit: Malin Space Science Systems –

Modern Exploration Global Surveyor Credit: Malin Space Science Systems –

Modern Exploration Global Surveyor Credit: Malin Space Science Systems –

Modern Exploration Global Surveyor Credit: Malin Space Science Systems –

Modern Exploration Global Surveyor Credit: NASA/Goddard Space Flight Center

Modern Exploration Global Surveyor  Notable 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 Exploration Global Surveyor  How 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