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A Martian Road Trip

by Perry Pezzolanella

The huge successes of the two Viking Landers, the Pathfinder Lander with Sojourner, the Mars Exploration Rovers, Spirit and Opportunity, and the Phoenix Lander have opened a new era in the exploration of Mars. The Viking Landers could not determine if life is present or ever was present on Mars, but did uncover clues that Mars had a warmer, wetter past. The Sojourner Rover proved that driving a wheeled vehicle on Mars was possible and found that the geological chemistry varied the more it roamed. The Opportunity Rover confirmed that Mars did indeed have water and in many places there were shallow pools or perhaps seas in its past. Where there was water, there may have been life or may still be. Sedimentary rocks on Earth leave a record of past life and only certain environments and types of deposits provide good places for fossil preservation. The challenge is to determine life from non-life as any life on Mars could potentially have a different chemistry, structure, and characteristics than on Earth. A huge rover, capable of taking a long road trip on the surface of Mars might be able to determine if Mars ever had an environment capable of supporting microbial life.

The $2.5 billion-dollar Mars Science Laboratory, now known as Curiosity, is just such a rover. Weighing in at 1875 pounds, it is as large as a small car and capable of lasting many years and traveling over ten miles. It will collect, grind, distribute, and analyze around 70 samples of soil and rock. The rover will have four main science goals:

1. Determine whether life ever arose on Mars. In order to know if there ever was a possibility of life on Mars, past or present, it is necessary to know if Mars ever had an environment capable of supporting life. Curiosity will look for chemical elements that are the building blocks for life. These are carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur. Life requires a stable environment, and while the rovers have found evidence of water in the past, the hazards of volcanic eruptions and ultraviolet radiation are also crucial.

2. Characterize the climate of Mars. Curiosity will study the atmosphere, which is now thin, cold, and dry. Mars may have had a thicker, warmer, wetter atmosphere that could have supported microbial life. The rover will be able to measure different isotopes in the rocks to help determine if there were any abrupt past changes in water, carbon dioxide, or hydrogen in the atmosphere that could have affected the climate.

3. Characterize the geology of Mars. A record of the past is recorded in layers of rock. Curiosity will study the rock and soil to try to understand the geological processes that created and modified the crust and surface. It will especially look for any creation and modification by water, whether flowing or standing.

4. Prepare for human exploration. Curiosity will demonstrate the feasibility of landing large payloads on Mars. It is such a large and heavy rover that it cannot land using airbags. It will be literally reeled to the surface using a rocket-powered skycrane. The crane will lower the rover to the surface on a tether and then detach. The skycrane will then fly away safely from the rover and crash in the distance. This type of controlled landing will allow for more precise future landings and make it possible to land in more difficult, but interesting areas such as volcanic peaks and winding canyons. This will develop the ability to send astronauts to a given location safely and reliably.

Curiosity has eight science objectives in order to meet its specific goal in determining if Mars was ever habitable. These include:

Biological objectives:

1. Determine the nature and inventory of organic carbon compounds.

2. Inventory the chemical building blocks of life (carbon, hydrogen, nitrogen, oxygen,

3. Identify features that may represent the effects of biological processes.

Geological and geochemical objectives:

4. Investigate the chemical, isotopic, and mineralogical composition of the Martian surface and near-surface geological materials.

5. Interpret the processes that have formed and modified rocks and soils.

Planetary process objectives:

6. Assess the atmospheric evolution process over the course of about 4 billion years.

7. Determine present state, distribution, and cycling of water and carbon dioxide.

Surface radiation objective:

8. Characterize the broad spectrum of surface radiation, including cosmic rays and solar radiation.

Curiosity is scheduled for launch this year between November 25 and December 18 and will arrive at Mars anytime from August 6 to 20, 2012. Since it will not use airbags, it will land with its wheels down in contact with the surface and ready to rove. It will be several days before it can roam as it must be checked out for any problems and to be sure that it landed firmly with no immediate hazards nearby such as boulders, dunes, and trenches. It will use this opportunity to return a panoramic photo of its landing site. Since it will be able to land in a more interesting landscape, the first pictures it returns to Earth could be awe inspiring. If everything checks out, Curiosity will be ready to begin the greatest road trip beyond Earth with the promise of adventure and discovery. In this case it might not be the destination that might be interesting, but the journey it takes along the way after arriving.