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Created byScott Taubitz

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Project Red-Cycle: Engineering Sustainable Martian Biospheres

Grade 9Science2 days

Project Red-Cycle challenges 9th-grade students to serve as bio-regenerative engineers designing a self-sustaining Martian biosphere. Students use mathematical modeling and biochemical analysis to balance carbon cycling, energy flow, and waste management within a closed-loop life support system. The experience culminates in a 3D habitat proposal defended before a "NASA Review Board," demonstrating how photosynthesis, respiration, and decomposition maintain homeostasis in an extreme environment.

MarsBiosphereCarbon CycleEnergy FlowBio-engineeringSustainabilityMathematical Modeling

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Inquiry Framework

Question Framework

Driving Question

The overarching question that guides the entire project.How can we, as bio-regenerative engineers, design and mathematically model a self-sustaining Martian biosphere that balances carbon cycling and energy flow to support a crew of explorers indefinitely?

Essential Questions

Supporting questions that break down major concepts.

How do the processes of photosynthesis and cellular respiration drive the continuous cycling of carbon within a sealed Martian habitat?
How can we use mathematical modeling to predict if our energy flow and nutrient cycles are sufficient to support a specific number of explorers?
In what ways does the transition between aerobic and anaerobic conditions affect the efficiency and stability of a closed-loop life support system?
How do decomposers and microbial life act as the 'engine' for matter cycling in an environment where no new resources can be added?
How can we design a system that minimizes energy loss while maximizing the recycling of carbon among the atmosphere, biosphere, and geosphere?

Standards & Learning Goals

Learning Goals

By the end of this project, students will be able to:

Develop a comprehensive model of a closed-loop biosphere that illustrates the interdependent roles of photosynthesis, cellular respiration, and decomposition in cycling carbon between the atmosphere and living organisms.
Use mathematical calculations and data-driven models to determine the necessary biomass, energy inputs, and gas exchange rates required to sustain a specific crew size on Mars.
Analyze and explain the biochemical differences between aerobic and anaerobic processes within the habitat, specifically focusing on how these processes impact nutrient availability and system stability.
Design an engineering solution that optimizes energy flow and minimizes resource loss, demonstrating an understanding of the 10% rule in energy pyramids and the laws of thermodynamics in a closed system.
Construct a scientific argument based on evidence from their models to justify the inclusion of specific microbial and plant species to maintain homeostatic balance in the Martian habitat.

Next Generation Science Standards (NGSS)

HS-LS2-3

Primary

Construct and revise an explanation based on evidence for the cycling of matter and flow of energy in aerobic and anaerobic conditions.Reason: This project requires students to explain how a Martian habitat cycles matter (carbon) and energy, specifically addressing the role of decomposers and waste management in both oxygen-rich and oxygen-poor environments.

HS-LS2-4

Primary

Use mathematical representations to support claims for the cycling of matter and flow of energy among organisms in an ecosystem.Reason: The driving question specifically tasks students with 'mathematically modeling' the biosphere. Students must calculate energy transfers and biomass requirements to ensure the crew can survive indefinitely.

HS-LS2-5

Primary

Develop a model to illustrate the role of photosynthesis and cellular respiration in the cycling of carbon among the biosphere, atmosphere, hydrosphere, and geosphere.Reason: The core of the Martian biosphere design relies on balancing the carbon exchange between producers (plants/algae) and consumers (humans/microbes) via photosynthesis and respiration.

Entry Events

Events that will be used to introduce the project to students

The Ares 1 Distress Call

Students enter a darkened room to a looping 'Emergency Alert' video from a fictional Mars colony where the CO2 scrubbers have failed. They are handed a 'Survival Ledger' showing rapidly declining oxygen levels and must immediately use provided data sets to calculate how many plants or anaerobic microbes would be needed to stabilize the atmosphere before the timer runs out.

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Portfolio Activities

These activities progressively build towards your learning goals, with each submission contributing to the student's final portfolio.

Activity 1

The Bio-Math Ledger

Design is nothing without data. In this activity, students transition from conceptual models to mathematical ones. They will use metabolic data for humans and gas exchange rates for various plants to calculate the exact biomass required to sustain one astronaut. Students will explore the '10% Rule' of energy transfer to understand why high-calorie crops are essential and how energy is lost as heat within the closed system.

Steps

Here is some basic scaffolding to help students complete the activity.

1. Research the average daily CO2 production and O2 consumption of a human performing 'Mars-normal' activities.

2. Calculate the 'Photosynthetic Productivity' of chosen crops (e.g., Spirulina algae vs. leafy greens) per square meter.

3. Use ratios to determine the total surface area of the greenhouse needed to balance the crew's respiratory needs.

4. Apply the 10% energy transfer rule to determine how much solar or artificial light energy must enter the system to produce enough biomass (food) for the crew.

Final Product

What students will submit as the final product of the activityThe 'Ares Survival Ledger'—a spreadsheet or mathematical report that justifies the habitat's population capacity based on energy flow and matter cycling.

Alignment

How this activity aligns with the learning objectives & standardsThis activity aligns with HS-LS2-4, as students must use mathematical representations (ratios, energy transfer percentages, and metabolic rates) to support their claims about how many organisms are needed to sustain the ecosystem.

Activity 2

The Red-Cycle Waste Engine

On Mars, there is no 'away.' Every gram of waste must be recycled. Students will design the 'Microbial Engine' of their habitat, focusing on how decomposers break down organic matter. They must decide between aerobic decomposition (which uses precious oxygen but is fast) and anaerobic digestion (which produces methane for fuel but is slower). Students will explain how these processes return carbon to the geosphere (soil) or atmosphere.

Steps

Here is some basic scaffolding to help students complete the activity.

1. Compare and contrast the energy yields and chemical byproducts of aerobic respiration vs. anaerobic fermentation.

2. Select a 'Decomposer Suite' (specific bacteria, fungi, or microbes) to manage the habitat's solid waste.

3. Diagram how the decomposers return carbon to the system, specifically looking at how nitrogen and phosphorus are also liberated for the plants.

4. Write a justification explaining how the chosen decomposition method affects the habitat's overall energy efficiency and oxygen levels.

Final Product

What students will submit as the final product of the activityA 'Waste-to-Wealth' Technical Manual that includes a flowchart of the decomposition process and a scientific argument for the chosen method (aerobic vs. anaerobic).

Alignment

How this activity aligns with the learning objectives & standardsThis activity meets HS-LS2-3 by requiring students to construct an explanation for the cycling of matter (specifically waste) in both aerobic (composting) and anaerobic (methanogen digestion) conditions.

Activity 3

The Red-Cycle Master Plan

As the final project milestone, students will synthesize their findings into a comprehensive 3D or digital model of the Martian Biosphere. This model must demonstrate a 'Steady State' where matter cycling and energy flow are perfectly balanced. Students will present their designs to a 'NASA Review Board' (peers and teacher), defending their engineering choices with the evidence and math gathered in previous activities.

Steps

Here is some basic scaffolding to help students complete the activity.

1. Integrate the Carbon Blueprint, the Bio-Math Ledger, and the Waste Engine into one cohesive habitat design.

2. Identify potential 'leaks' or inefficiencies in the system (e.g., energy loss through heat) and propose engineering solutions to minimize them.

3. Simulate a 'System Shock' (e.g., a crop failure or a power outage) and revise the model to show how the habitat can return to homeostasis.

4. Present the final design, using evidence-based arguments to explain how carbon and energy flow through every part of the dome.

Final Product

What students will submit as the final product of the activityThe 'Red-Cycle Master Proposal'—a physical or digital 3D model accompanied by a summary presentation that proves the system can support life indefinitely.

Alignment

How this activity aligns with the learning objectives & standardsThis final activity integrates HS-LS2-3, HS-LS2-4, and HS-LS2-5. Students must revise their earlier explanations based on peer feedback and ensure their model illustrates the complete carbon cycle across all four spheres (biosphere, atmosphere, hydrosphere, geosphere).

Activity 4

The Carbon Exchange Blueprint

In this foundational activity, students will map the chemical 'handshake' between producers and consumers. Using the scenario of the Ares 1 distress call, students must create a detailed visual system map that shows how carbon dioxide exhaled by the crew is transformed into oxygen and glucose by the greenhouse module, and how that glucose is cycled back to the crew for energy. This activity establishes the conceptual framework of the closed-loop system.

Steps

Here is some basic scaffolding to help students complete the activity.

1. Identify the primary biological components of the biosphere (e.g., humans, specific Martian crops like potatoes or algae).

2. Diagram the chemical inputs and outputs for both photosynthesis and cellular respiration, using arrows to show the flow of carbon atoms.

3. Annotate the map to explain how the atmosphere (the air in the habitat) acts as a bridge between the plant and human modules.

4. Define the 'Carbon Balance'—calculate the ratio of oxygen produced to carbon dioxide consumed to ensure atmospheric stability.

Final Product

What students will submit as the final product of the activityA 'Carbon Flux System Map' showing the inputs, outputs, and chemical formulas for photosynthesis and cellular respiration as they occur within the Martian habitat.

Alignment

How this activity aligns with the learning objectives & standardsThis activity directly addresses HS-LS2-5 by requiring students to develop a model that illustrates the role of photosynthesis and cellular respiration in the cycling of carbon between the biosphere (plants/humans) and the atmosphere (CO2/O2 levels).

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Rubric & Reflection

Portfolio Rubric

Grading criteria for assessing the overall project portfolio

Project Red-Cycle: Martian Biosphere Design Rubric

Category 1

Energy and Matter Dynamics

Focuses on the quantitative and conceptual modeling of energy flow and matter cycling within the closed system.

Criterion 1

Quantitative Modeling of Energy & Biomass (HS-LS2-4)

Evaluates the accuracy and depth of mathematical representations used to calculate energy transfers, biomass requirements, and metabolic rates within the Martian habitat.

Exemplary

4 Points

Mathematical models are sophisticated and error-free, integrating multiple variables (metabolic rates, photosynthetic productivity, 10% rule) to predict long-term sustainability. Insights show an advanced understanding of energy loss as heat.

Proficient

3 Points

Mathematical models accurately use ratios and percentages to determine the biomass and energy needed to sustain the crew. Calculations for the 10% rule and gas exchange are correct and clearly documented.

Developing

2 Points

Mathematical models are present but contain minor inaccuracies or lack depth. Some calculations for energy transfer or biomass requirements may be inconsistent or incomplete.

Beginning

1 Points

Mathematical representations are incomplete, inaccurate, or fail to support claims about habitat capacity. Basic concepts like the 10% rule or metabolic ratios are missing or misunderstood.

Criterion 2

Carbon Flux and Gas Exchange Modeling (HS-LS2-5)

Assesses the student's ability to model the interdependent roles of photosynthesis and cellular respiration in cycling carbon between the atmosphere, biosphere, and other habitat spheres.

Exemplary

4 Points

The model provides a sophisticated, multi-sphere illustration of carbon cycling. It innovatively maps the chemical 'handshake' between producers and consumers with precise chemical formulas and nuanced atmospheric balance predictions.

Proficient

3 Points

The model clearly illustrates how photosynthesis and cellular respiration cycle carbon between the plants and humans. Atmospheric bridges (CO2/O2 exchange) are correctly identified and annotated.

Developing

2 Points

The model identifies the primary components of carbon cycling but lacks detail in the chemical transitions or fails to show the continuous flow between different habitat modules/spheres.

Beginning

1 Points

The model is missing key components of the carbon cycle or contains significant misconceptions regarding the relationship between photosynthesis and respiration.

Category 2

Bio-Regenerative Systems

Assesses the understanding of biochemical processes that ensure resource circularity.

Criterion 1

Microbial Engines & Matter Cycling (HS-LS2-3)

Evaluates the explanation and justification of aerobic and anaerobic processes used to manage waste and return nutrients to the ecosystem.

Exemplary

4 Points

Provides a nuanced analysis of the trade-offs between aerobic and anaerobic decomposition, explaining their impact on system enthalpy, nutrient liberation (N and P), and oxygen budget with high technical precision.

Proficient

3 Points

Constructs a clear, evidence-based explanation for the chosen decomposition method. Correctly identifies the chemical byproducts and energy yields of aerobic vs. anaerobic processes within the habitat.

Developing

2 Points

Explains the role of decomposers but provides an incomplete comparison of aerobic and anaerobic conditions. The link between waste management and nutrient availability is weak.

Beginning

1 Points

Fails to distinguish between aerobic and anaerobic processes or provides an inaccurate description of how matter is recycled from waste back into the system.

Category 3

Engineering Design & Communication

Focuses on the integration of all project components into a final, viable Martian habitat proposal.

Criterion 1

System Synthesis & Homeostasis

Evaluates the ability to synthesize components into a cohesive system that maintains homeostasis and responds to environmental stressors.

Exemplary

4 Points

The master plan demonstrates exceptional system integration, identifying subtle inefficiencies and proposing innovative engineering solutions. The response to 'System Shock' is robust, evidence-based, and restores equilibrium.

Proficient

3 Points

The master plan integrates the math ledger, carbon blueprint, and waste engine into a functional 3D model. The design effectively addresses potential leaks and shows a clear path back to homeostasis after a shock.

Developing

2 Points

The final design is functional but lacks integration between the different modules (e.g., waste engine doesn't clearly support the greenhouse). The response to system failure is superficial.

Beginning

1 Points

The final plan is fragmented or non-functional. The model fails to demonstrate how carbon and energy flow through the system as a whole.

Criterion 2

Evidence-Based Argumentation

Assesses the quality of the scientific argument and the use of evidence from activities to justify engineering choices to the 'NASA Review Board.'

Exemplary

4 Points

Arguments are compelling, sophisticated, and rooted in deep scientific evidence. The student expertly defends complex choices (e.g., specific microbial suites or crop selection) during the review.

Proficient

3 Points

Constructs a solid scientific argument using data from the previous activities. Justifications for species selection and energy inputs are supported by the student’s own mathematical and conceptual models.

Developing

2 Points

Arguments are present but lack sufficient evidence or rely on generalizations. The connection between the data gathered and the final design choices is not always clear.

Beginning

1 Points

The presentation lacks a scientific argument or evidence-based justification. Engineering choices appear arbitrary rather than data-driven.

Reflection Prompts

End-of-project reflection questions to get students to think about their learning

Question 1

How did your understanding of the relationship between photosynthesis and cellular respiration change from the initial 'Ares 1 Distress Call' to your final 'Red-Cycle Master Plan'?

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Required

Question 2

Based on your 'Bio-Math Ledger,' how confident are you that your mathematical model accurately accounts for energy loss (10% rule) and gas exchange to support your crew indefinitely?

Scale

Required

Question 3

Which aspect of the carbon cycle or energy flow was the most difficult to 'balance' within your closed-loop engineering design?

Multiple choice

Required

Options

Maximizing oxygen production while minimizing CO2 buildup.

Choosing between aerobic and anaerobic decomposition for waste.

Accounting for the 10% energy loss between trophic levels.

Maintaining the carbon balance between the atmosphere and geosphere.

Question 4

When you simulated a 'System Shock' (e.g., crop failure), what specific evidence from your model led you to your solution, and how did that change reflect the cycling of matter in a closed system?

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Required