Surface Exploration of Mars: Past & Future Martian Meteorites Martian Moons Martian Surface Exploration The Viking Landers (early 80s) Pathfinder (1997) Current Surface Explorers (three en route!) Future of Martian Exploration (“astrobiology”) Review of Mars

What are these “meteorites”? Martian Meteorites Why aren’t they orange – the color of Mars surface? How did they get to Earth? How do we know these meteorites are from Mars? Martian data without going there! Unusual rocks found in Antarctica An impact on Mars (crater size: km) ejected part of the Martian surface Chemical composition does not match usual meteorites Only 1.3 billion yrs old (most asteroid-type meteorites MUCH older); Higher content of volatile substances Has to do with how the rocks weathered

Case Study: Martian Rock ALH84001 Mass = 1.9 kg Igneous Rock Discovered in Antarctica (easier to find) 1984 Formed on Mars 4.5 Billion yr ago Ejected ~16 Million yr ago Landed ~13,000 yr ago What DO they tell us? What DON’T they tell us? -Physical processes on Mars Crust/core developed early in Solar System Volcanism until < 1 Billion Years ago - Chemical composition Different than normal asteroid (meteorite) comp. Interaction with water Martian atmosphere composition - Location of origin (on Mars – which part of surface?) - Enough about Mars’ water & atmosphere - Need to actually RETURN ROCKS from Mars!!

Globules of carbonate minerals (the yellow-orange grains) are scattered along cracks in this small chip of ALH The rims contain iron oxides (including magnetite) and iron sulfides--incompatible minerals that on Earth would suggest microbial action Controversial – microbial presence in meteorites?? Close up views reveal structure similar to Earth microbes? Astrobiology: exciting field of research – study of origin of life in the solar system,universe - LIFE IS UBIQUITOUS in the universe – we just haven’t found it - LIFE IS A SPECIAL quirk of nature and timing – very very rare!

Phobos (20 km x 27 km) Comparison: Asteroid Eros (33 km x 13 km) Martian Moons Deimos Two moons: Deimos, Phobos Small (~20km) irregularly shaped Orbit Mars in 8hr, 30hr Probably captured asteroids

Risks of Solar System Missions PROS for Space Missions Closest views of the planets that are possible Access to wavelengths that are unavailable on the ground Atmospheric effects gone – get clearer views than on Earth Development of sophisticated tech. and research CONS for Space Missions + Can not fix/test equipment as easily + Large risk with rocket launch + Much much more costly! (although more costly for manned than unmanned) + Lifetime is usually shorter + Upgrades much more difficult + Risks from UV radiation, cosmic rays

Viking Landers 1 and 2 Viking 1 launched in August of 1975, Viking 2 launched in Sept Vikings arrived at Mars in June, August of 1976 Orbiter + Lander – Orbiters alone weighed close to a ½ ton each – very expensive launch/rocket equipment !! - these days NASA’s mantra: “Faster Better Cheaper”

Viking Lander Images of Mars’ Surface landing site chosen from Orbiter images – two different regions in Northern Lowlands revealed that the surface of Mars was littered with jagged rocks and fine dust everywhere rocks were probably result of crater-forming impact (“ejecta”) rocks resemble lava-rocks on Earth – lava flows broken up by impacts

Viking Landers: Search for Life on Mars Science Instruments: - chem lab to explore reactions of Mars rock with water (none detected) - scoop arm with magnet – found that the soil was IRON-rich confined to study only one part of Martian surface – its landing site inspired NASA to propose for missions with MOVING surface vehicles – Pathfinder 1997!

Mars has a very thin atmosphere and no magnetosphere. If humans populated the Martian surface, what environmental problems will they be concerned about? (1) Global Warming (2) Solar flare particles and ultraviolet radiation (3) Nitrogen poisoning (4) Lead contamination from volcanoes (5) Magnetic anomalies in the interior causing brain disorders

Mars Pathfinder Mission – landed on Mars 4 July 1997 Demonstration mission for “Faster Better Cheaper” NASA mantra used lightweight airbags to land small, efficient robotic vehicle 10x as many images as previous missions (computers) landed 500 miles from Vikings – flood plain area (volcanic rocks with silicon)

Panoramic View from Mars’ Pathfinder’s Sojourner Rover

ATHENA: MARS EXPLORATION ROVERS Opportunity & Spirit (or MER A and MER B) Launched in June and July of 2003 arrival at Mars – January 2004 Each Rover weighs 180 kg, is ~5 ft high surface exploration: travels 100m per day Rover

ATHENA: MARS EXPLORATION ROVER Mars Rover Entry Sequence

cartoon of the “airbag” landing of the Mars Exploration Rovers on surface

Choosing a site to land on Mars Can not just land anywhere – need to consider the safety of the vessel! - previous missions have landed in the northern lowlands

Mars Landing Considerations terrain - altitude (impossible climbs, falls) - slopes (use too much energy) - rockiness (protect airbags) solar panel heating – keep rover operable dust - solar panels clear - RAT tool works more in thick dust

Science Objectives of the MER mission Characterize a variety of rocks and soils that hold clues to past water activity – i.e. try to identify carbonates (indicate water-volcano cycles) Distribution and composition of minerals, rocks, and soils near sites Determine geologic processes have shaped the local terrain Perform "ground truth" – calibration and validation – of surface observations made by Mars orbiter instruments.

Mars Exploration Rover: Science Instruments Pancam- Stereo camera IR Spectrometer - rock composition X-ray Spectrometer - soil and rock chemistry RAT - rock abrasion tool Microscopic imager (search for fossils?)

Landing Sites on Mars: 1. Gusev Crater - morphological - 15 degrees South of Mars’ equator - large crater feature with several ‘channels’ leading into it - water may have pooled in crater during first 2 billion years “channel”

Landing Sites on Mars: 2. Meridiani Planum - mineralogical - 2 degrees South of Mars’ equator - other side of planet from Landing Site 1 - place where hematite has been found (rust-like mineral) – indicates that it is a former dried lake bed

Mars Express – European Effort

MARS EXPRESS Launched June 2003 Radar instrument (MARSIS) built at University of Iowa (Prof. D. Gurnett, P.I.) other instruments, including a small rover called “Beagle 2”

MARS EXPRESS: Radar Experiment Radar reflection signal of water is very different from rock Echoes can differentiate between rock and ice or water Radar transmitter operates at 1-2 MHz and penetrates ground to several km depth Probably cannot distinguish between CO 2 and H 2 0.

Mars Surface Exploration – the Future!

Future Mars Exploration: “Scout Missions” lightweight/efficient ballons fleet of small aircraft to explore Mars develop new technology also SAMPLE RETURNS

Martian Outpost: 2030