Students Measure CO2 18 Miles Above the Earth

co2 sensor in atmospheric launch balloon

Students at Colorado State University designed an experiment to measure changes in carbon dioxide levels at different altitudes using a CO2 sensor carried by a weather balloon. The results of their experiment will be published through the Colorado Space Grant Consortium.

According to the team representative Jeff Gier, the team launched the balloon and payload from Deer Trail, Colorado on August 2nd. The balloon traveled to about 96,000 vertical feet (29,260 meters) before bursting and falling back to the earth.

carbon dioxide sensor payload

In order to obtain the most accurate CO2 level readings, the incoming air was conditioned by the use of a heating chamber and moisture filter. A micro pump forced the conditioned air across a K-30 CO2 sensor fitted with a sampling cap at a consistent flow rate, then expelled back into the atmosphere.

co2 heater

Click "Air Flow Diagram" on right to see details.

“During our flight, the sensor worked as expected, but a payload malfunction inhibited our ability to take correct readings on the ascent,” said Gier. The students did not realize that the heater needed to be warmed up for 15 minutes before use. 

“Because of our lack of experience with the balloon launch schedule only about 4 minutes of warm-up time took place.  This caused our readings to increase to nearly 500 ppm,” he added.

Fortunately, by the time the payload reached maximum altitude, the heater was fully warmed, and on the descent the readings were correct. 

Jeff noted that their readings only went up to 42,000 feet. Beyond that height, the readings were too close to zero due to low atmospheric pressure. He believes that in the future a pressurized sensing chamber could allow readings to be taken up to a much higher altitude.

Since 1989, over 5,000 students have been directly involved in the Colorado Space Grant Consortium’s hands-on space hardware programs. Working with NASA, they have launched three rockets, three Space Shuttle payloads, two orbiting satellites (3CornerSat & Hermes), 10 sounding rocket payloads, 3 long-duration high altitude balloon payloads, and over 300 short-duration high altitude balloon payloads. In addition, students work on autonomous robotics projects and engage in telescope observing research and other faculty-led, space-focused research projects.

Posted by CO2 Meter on September 15, 2014.
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