Date of Award

January 2021

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Space Studies

First Advisor

Sherry K. Fieber-Beyer

Abstract

Asteroids are small, undifferentiated bodies that materialized during the formation epoch of the solar system. With a concerted effort to establish a long-term presence in space, crewed missions to asteroids should not be ignored. A critical aspect of human missions is self-sustainability, primarily growing crops via in-situ resource utilization. CI carbonaceous asteroids are a primitive type of asteroid that retain elements found during that early solar system formation. More importantly, the regolith on these asteroids contains soluble elemental nutrients, such as phosphorous and potassium, that crops can use for growth and development. This thesis focuses on the ability of CI carbonaceous asteroid regolith simulant to sustain plant growth and produce edible biomass of lettuce (Latuca sativa), radishes (Raphanus sativus), and peppers (Capsicum annuum). This study was split into three experiments. Experiment one tested growing the selected crops in increasing mixtures of simulant and peat moss. The second experiment focused on a mixture of simulant and perlite. The final experiment tested the simulant/perlite mixture in simulated microgravity. The results showed clear decreases in germination, plant height, leaf area, and biomass of the crops in the simulant/peat moss mixtures, with no germination growth in pure simulant. Additionally, there was no germination or growth in the simulant/perlite experiments. Subsequent analysis of the simulant showed that the simulant contains plant-usable nutrients, though it has a high pH, low CEC, and is a silt-based soil. These results indicate that the simulant is prone to compaction and crusting, leading to drought stress on the crops. Further investigations are to be needed to assess the effect of plant waste or compost on improving fertility of the simulant conducive for plant growth.

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