Improved High-Altitude Balloon for Microplastic and Extremophile Collection

Microplastics, microscopic plastic particles ranging from 100 nm to 5 mm, have been detected in nearly all environments on Earth. Secondary microplastics, which originate from the degradation of macroplastics such as synthetic textile fibers, are of particular concern. Their atmospheric transport remains poorly understood, and potential interactions with extremophiles—microorganisms that thrive in extreme environments—have yet to be studied. Building upon prior research, this study employs an improved high-altitude balloon payload to collect airborne microplastics and microorganisms between 20 km and 30 km. Significant enhancements increase efficiency, reliability, and sample collection volume. Key upgrades include a brushless motor, low-friction mechanical components, and an advanced electronics suite, all contributing to improved flow rate, power efficiency, and data collection. Mechanically, the payload now features ball bearings in all pulleys to reduce friction, and a brushless motor replaces the previous model for better efficiency and heat dissipation. The new motor is significantly more powerful, increasing airflow rates and sample collection speed, thereby enhancing the likelihood of capturing viable samples. The electronics system has been upgraded with an Espressif ESP32-S3 microcontroller, replacing the Teensy 4.1. This transition reduces power consumption while enabling simultaneous data logging and real-time communication. The addition of an Adafruit CAN Bus transceiver enhances motor control by enabling precise commands and feedback through the CAN protocol, improving reliability and noise resistance. A dedicated SD card module now ensures continuous logging of altitude, motor performance, pressure, and temperature, safeguarding critical flight data even when wireless communication is unavailable. The payload collects air through a sterile filter using a bellows system at rates up to 0.6 cubic meters per minute. A pressure sensor determines altitude and automatically seals the filter at 15 km to prevent contamination during descent. The system is powered by 12 18650 lithium-ion batteries in 6S2P configuration and features three redundant GPS systems to ensure accurate tracking. Collected microplastics (≥10 μm) will be analyzed using Raman Spectroscopy to determine chemical composition, while microbial samples will undergo PCR and 16S rRNA sequencing to identify extremophiles and assess their interactions with microplastics. By analyzing these samples, the study aims to explore potential biological responses to synthetic particulates in the stratosphere. Fairbanks, Alaska, was selected as the primary launch site due to its low human activity and favorable conditions for studying microplastic transport. Atmospheric processes such as wind currents, convection, and turbulence facilitate microplastic movement, making this location ideal for investigating long-range transport mechanisms. Houston, Texas, serves as a secondary collection site for comparative analysis of microplastic deposition in urban and rural environments. This project is part of the Undergraduate Student Instrument Project (USIP) at the University of Houston, a student-led initiative for high-altitude research. By improving upon previous designs, this study enhances our ability to measure microplastic concentrations in the stratosphere and examine their potential interactions with microbial life. The refined instrument increases data reliability, providing deeper insight into the environmental implications of atmospheric microplastics.