Learning Objectives
- Distinguish geomorphic, mineralogical, stratigraphic, and in situ chemical evidence for water.
- Assign confidence levels while acknowledging ambiguous interpretations.
- Connect Mars mission measurements to habitability claims without overstating the evidence.
Preparation
Review Lecture 8 on Mars water, climate evolution, rover exploration, and habitability evidence.
Materials and Data
../data/lab-05-mars-water-evidence.csv, a curated table of named Mars sites, missions, evidence types, measured quantities, and uncertainty notes.- Colored pens or annotation software for an evidence matrix.
- NASA Mars mission science summaries for Mars 2020, MER Opportunity, MRO CRISM/HiRISE, and MSL Curiosity.
Apparatus and Setup
- Open the CSV and create columns for evidence class, water timescale, confidence score, and alternate explanation.
- Use this confidence scale: 3 = strong evidence for sustained past liquid water, 2 = water-related but environment or duration uncertain, 1 = ambiguous or contested, 0 = not water evidence by itself.
- Prepare a one-page matrix with rows for sites and columns for geomorphology, mineralogy, chemistry, stratigraphy, and ambiguity.
Procedure
- Classify each site or feature by evidence type: geomorphic, mineralogical, stratigraphic, chemical, or seasonal surface-change observation.
- Assign a confidence score using the scale in the setup. Justify every score with a measured quantity from the CSV.
- Identify the strongest case for a long-lived habitable environment and the weakest case for present liquid water.
- For Jezero delta and Gale crater mudstone, compare whether the evidence is primarily shape-based, composition-based, or stratigraphic.
- Write a mission recommendation: which one site should receive a follow-up sample or measurement, and what measurement would reduce the largest uncertainty?
Measurement Record
| Site or feature | Evidence class | Measured quantity used | Confidence score | Primary ambiguity |
|---|---|---|---|---|
| Jezero delta | fan front width | |||
| Meridiani Planum | spherule abundance | |||
| Mawrth Vallis | phyllosilicate units | |||
| Recurring slope lineae candidate | slope angle | |||
| Gale crater mudstone | mudstone interval |
Analysis and Uncertainty
Treat numerical uncertainty as listed in the CSV. Treat confidence score as classification uncertainty: if two students could reasonably differ by one point, mark the score as plus or minus 1 and explain the disputed assumption. Present-water claims require stricter evidence than ancient-water claims because salts, slope streaks, and dry granular flows can mimic liquid-related features.
Deliverables
- Completed evidence matrix with confidence scores and ambiguity notes.
- Ranked list of the five sites from strongest to weakest water evidence.
- One 300-word recommendation for a follow-up measurement or sample target.
- Provenance note naming the NASA mission pages and
lab-05-mars-water-evidence.csv.
Assessment Criteria
- Evidence classes and confidence scores are justified with data: 30%.
- Uncertainty discussion distinguishes measurement error from interpretive ambiguity: 25%.
- Ranking separates ancient water evidence from present liquid-water claims: 20%.
- Follow-up recommendation targets a real unresolved measurement: 15%.
- Complete provenance note: 10%.
References, Software, and Data Provenance
Data file: materials/ASTR120/data/lab-05-mars-water-evidence.csv. Sources: NASA Mars 2020 Jezero crater science pages, MER Opportunity results, MRO CRISM and HiRISE observations, and MSL Curiosity science results. Processing state: curated teaching table assembled from public mission summaries with simplified measurement fields.