Getting Dirty on Mars

Phoenix Mars LanderEducator Conference

August 1-3, 2007

Brian GrigsbyAssistant Director

Mars Education ProgramCoordinator, MESDT

Arizona State UniversitySchool of Earth and Space Exploration

Goals/Objectives• Goals:

– Participants will understand the similarities and differences between soil properties on Earth and Mars.– Upon completing this activity, participants will understand and be able to determine if the soil sample will

support life.• Objectives:

– Participants will list and describe importance of soil properties– Participants will use a soil test kit to determine soil properties such as pH levels, and specific chemical levels.– Participants will use Earth soil analogs to understand the kinds of tests being performed by spacecraft on

Mars.– Participants will assess soil samples for habitability

What might Phoenix find?What might Phoenix find?

• Phoenix will test the soil for life-giving elements such as carbon, nitrogen, phosphorus, and hydrogen.

• But even if the Martian soil contains the right mix of ingredients to sustain life, it may also contain hazards that prevent biological growth, such as powerful oxidants that break apart organic molecules.

• These harmful oxidants are often found in dry environments that are bathed in ultraviolet light, such as the surface of Mars.

• But just a few inches below the surface, the soil could protect organisms from the harmful solar radiation.

• The Phoenix lander has a suite of instruments designed to characterize the martian environment

• These instruments characterize the soil of Mars much like a gardener would test the soil in his or her yard.

• By dissolving small amounts of soil in water, some of these instruments can determine the pH, the abundance of minerals such as magnesium and sodium cations or chloride, bromide and sulfate anions, as well as dissolved oxygen and carbon dioxide.

Science instrumentsScience instruments

Why study soils?SOIL:• Is critical component of Earth’s ecosystem.• Holds water and nutrients. • Is important to farmers, as the properties of a

particular kind of soil determine what crops will grow best in it.

• Can change the chemistry of groundwater (e.g., acidity, saltiness).

• The type of soil in a region will determine whether groundwater will collect in an area for use by its inhabitants or if it will run off downstream, eroding the landscape.

• Helps regulate Earth’s temperature and its atmosphere.

• affects the types of gases released into the atmosphere as well.

• Microbes living in the soil break down organic material into nutrients that can be used by plants.

• Soil is critical to life on Earth, so it is important that we understand its properties.

How is it related to Mars Exploration?How is it related to Mars Exploration?

– Just as on Earth, the pedosphere (the outermost layer of a planet’s surface, primarily composed of soil) of Mars can tell us a great deal about the planet’s history and whether Mars was ever capable of supporting life, or could support life in the future.

Soil Properties overview—part 1Soil Properties overview—part 1• In this series of activities you will work with a team of other researchers (4 to a team) to conduct

experiments on soil samples (activities 1 and 2).• For the first part of the experiment, you will collect a soil sample from a designated landing site

indicated on your “Collection Site Doubletree” image. • Once in the field, look for the soil sample location your team has been given.• Be sure to make note of the Soil Context (the environment where the soil is found)• To gather the sample, follow the instructions in the activity description.• Once you have returned to the “lab” your team will separate the soil into labeled baggies:

1. Equatorial region2. Mid-latitudes3. Polar regionThe control will be a few seeds placed between moist paper towels, and sealed in a baggie.

• On the 3rd day, we will assess the seed growth, and measure the chemical properties of the soil.

MSL Candidate Landing Site: Nili Fossae Trough: Thermal Inertia on Day IR

1 of 36 candidate landing sites

Phoenix Mars Lander with Arm Extended, Artist's Concept

Materials neededMaterials needed

• Soil Context (characterization)– “Collection Site” image

• Sample Collection Procedure– “Scoop”

– Ziplock baggies (4)

• Habitability (Part 1)– Seeds

– Separated soil samples

ProcedureProcedure

• Locate your team’s collection site number• Follow the collection procedures• Separate the sample into 3 different ziplock baggies,

leaving a small amount for chemical testing later• Label your samples with your team number• Extension:

– Place some of the provided sample into the baggies to test for habitability

Soil Properties/Habitability—Part 2Soil Properties/Habitability—Part 2

Before you begin…Before you begin…

IMPORTANT NOTE:In order for the N-P-K test to have time to work for this session follow

these instructions:

1. Using the craft stick, place 2-3 scoops of soil into the provided container.

2. Place the cap back on the container firmly and shake to mix the soil and water.

3. Set this sample aside to allow the soil to settle.

ControlControl

Soil Properties/Habitability—Part 2Soil Properties/Habitability—Part 2Activity 3

Soil StructureMaterials needed:•Small amount of soil•Magnifying glasses•Metric ruler

Chemical Analysis, pH, N-P-KMaterials needed:•Small amount of soil•Craft stick•Soil test capsules•Soil test chamber (clear bottle)•Distilled water (in squeeze bottle)•Gloves•Plastic bottle with lid for N-P-K soil solution

Habitability assessmentMaterials needed:•Baggies with seeds

Activity question/discussionActivity question/discussion

• Soil Structure (physical property)– How would the soil structure be an important factor in

determining habitability (see descriptions at the end of the lesson)?

• Chemical analysis:– Based on your results, what would be the initial conclusion

regarding the habitability of the soil?

– Based upon the information gained at the soil collection site, would this be a good or bad location to look for evidence of life?

– Knowing that current technology can only allow spacecraft to dig a meter or so below the surface, would it be worth the effort to find ways to dig deeper? Why or why not?

Factors influencing habitabilityFactors influencing habitability

• Temperature– Affects how molecules behave, such as whether water is found as a solid,

liquid or gas.

• Water– Dissolves and transports chemicals within cells

• Atmosphere– Traps heat, shields the surface from harmful radiation, and provides

chemicals needed for life, such as nitrogen and carbon dioxide.

• Energy– Organisms use light or chemical energy to run their life processes.

• Nutrients– Used to build and maintain an organism’s body.

• What would happen to the factor if you increased, decreased or left the factor the same?

• How would Earth and Mars compare with each of these factors?

Conclusions (Earth/Mars)Conclusions (Earth/Mars)

• What can soil structure tell us?– Soil structure is the shape that the soil takes based on its physical and chemical properties. (i.e. clays

in the soil cause the material to clump)• What can carbonates tell us about the surface?

– Past water activity, (possible life?), caliche (hardpan, less fertile)• Why is pH important?

– This determines the kind of organisms that can live in the soil.– Bacteria have adapted to live in environments close to a neutral pH.– Extremophiles

• Why is nitrogen, phosphorus and potassium (N-P-K) important?– Because the soil carries in it nutrients such as nitrogen (N), potassium (K), and phosphorus (P) that

plants need in specific amounts to grow, thrive, and fight off diseases. – If the pH of the soil solution is increased above 5.5, nitrogen (in the form of nitrate) is made available to

plants. – Phosphorus, on the other hand, is available to plants when soil pH is between 6.0 and 7.0. – Certain bacteria help plants obtain nitrogen by converting atmospheric nitrogen into a form that plants

can use. These bacteria live in root nodules of legumes (like alfalfa and soybeans) and function best when the pH of the plant they live in is growing in soil within an acceptable pH range.

– For instance, alfalfa grows best in soils having a pH of 6.2 - 7.8, while soybean grows best in soils with a pH between 6.0 and 7.0. Peanuts grow best in soils that have a pH of 5.3to 6.6. Many other crops, vegetables, flowers and shrubs, trees, weeds and fruit are pH dependent and rely on the soil solution to obtain nutrients.

– If the soil solution is too acidic plants cannot utilize N, P, K and other nutrients they need. In acidic soils, plants are more likely to take up toxic metals and some plants eventually die of toxicity (poisoning).

Soil CompositionsSoil Compositions

•GSVCC-A (Gilbert, Sun Valley Community Church)

– nitrogen

•GSVCC-B

– phosphate (bonemeal)

•NAASU-A (Northern Arizona, Arizona State University)

– potash

•NAASU-B

– nitrogen, baking soda

•NAASU-C

– nitrogen, bleach

•MSS-A (Mars Soil Simulant)

– potash, vinegar

•MSS-B

– baking soda

• LCOS (Lincoln City Oregon Sand)

– phosphate, vinegar

• ROPS-A (Regular Old Play Sand)

– potash, baking soda

• ROPS-B

– nitrogen, baking soda

• MFYS-A (My Front Yard Sample)

– phosphate

• MFYS-B

– potash, nitrogen

• HBE (Hawaiian Beach Exotic)

– vinegar, potash, nitrogen, phosphate

Contact Info

Brian GrigsbyAssistant Director

Mars Education ProgramDistance Learning Coordinator

Contact infoBrian.Grigsby@asu.edu

480-965-5514

Mars Education Website:http://marsed.asu.edu