por

In a closed-loop lunar environment,
using human waste to create a water barrier structure to shield against cosmic radiation.

Spark Awards Finalist

Global Gradshow 2018

In 2030, as we move on to the Moon and explore deep space further, how can we manage human waste for long-term lunar missions?

This project is developed under the vision of Earth-Moon partnership. In 2030, as we move on to the Moon and explore deep space further, the extreme limitations of resources and support challenges us to think urgently to create a closed-loop system for Lunar Outpost Mission. 

Astronaut Scott Kelly will produce about 180 pounds of feces that will burn up in the atmosphere and look like shooting stars.

Highlight from Scott Kelly’s year long endurance mission

In current space missions, we still depend on Earth to resupply materials and process human waste.
 
However, as we inhabit the Moon and other locations in space, this will not be possible nor sustainable.
How does the current process work on the space station?
Why won’t the current process work for deep space exploration? 
Human waste is not processed instantly 
Dependent on Earth
A linear system

In order to recycle optimally, current process on the ISS1* involves multiple devices to filter, compress and conduct chemical reactions. The cost of time and space from this inefficiency is expensive.

This management requires various types of containers to collect and store solid human waste. Not only does this waste system rely on Earth to resupply containers, it also depends on Earth to incinerate the collected waste.

Without any recycling or repurposing solutions for the collected waste, this potential resource is shipped out, to burn up in the Earth’s atmosphere during fiery re-entry.

Conducting Life Cycle Assessment (LCA) to understand the environmental impact at each stage.

Life Cycle Assessment is a tool to understand the environmental impact of a product or system. Combined with Okala Impact Factors, it helps me to quickly model the overall impact of the current human waste management on ISS.

 

The assessment aligns with the previous research but with a perspective of environmental performance. Current management is a linear system. And it shows that the majority of the impact results from the disposal and the usage of containers.

Refining the current system is not enough. 
What can we do to recycle and re-purpose human waste and create a closed-loop system on the Moon?
We can benefit from the high performance of water and plastic to mitigate cosmic radiation, and develop a repurposed human waste plastic product for lunar habitat.
Solution
por: Using human waste converted plastic to create a water barrier structure to shield against cosmic radiation.
Design Process
1. The design toolkit for por
Adapt Advanced Life Support (ALS) technologies for ISRU

Torrefaction (mild pyrolysis) processing has shown a promising result to sterilize feces and produce stable, solid product. 

 

This study indicates the potential benefit of repurposing this residue from human waste into a plastic.

Water wall serves as radiation shield

The POR system will be used to construct a habitat with this new plastic from human waste.

 

In combination with water, the POR habitat is more effective than lunar regolith*5 in shielding against cosmic radiation.

Bio-inspired

Inspired by nature, a panel unit incorporates the reticulate venation found in leaves and forms a vascular system for the habitat. 

 

This vascular network facilitates water transport and provides mechanical resilience.

2. Translate the structure of plants to a lunar habitat with vascular system
Constraints of the lunar habitat
Radiation:
Provide radiation protection to mitigate the dose <50 rem/yr.

Material:

- Repurposed plastic, assume it could become printable material.

- Water, which will have dual usage in the future.

Structure:

- Rigid over inflatable for long-term Lunar Outpost Mission

- Spherical/ Cylindrical form to endure even radiation dose and avoid pressure tension.

Modular system. Easy to replace and repair.

Development of the vascular system and the leaf panel unit

Use the reticulate typed venation to create a network-like vascular system for water transport. 

3. Use dome as an example to design this lunar habitat form.
Final Design

Scaled model of the por habitat and its panel unit.

How por works
The new human waste management process:
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All works © 2019 by Shu Ou