SPIRIT II's Trimethyl Aluminum Release Experiment
Atmospheric scientists have used Trimethyl Aluminum or TMA releases for decades as a tracer element of the neutral winds of the upper atmosphere. TMA is a chemical that burns brightly when it comes into contact with oxygen--as it is released from the payload during the rocket's flight, it leaves a chemical trail behind. At night, the trail glows brightly and can easily be seen and photographed from earth. Over time, the trail becomes deformed due to the interaction with neutral wind, by taking photographs, the position and velocity of the trail as it deforms may be determined.
The negative image below shows two TMA trails and an artificial aurora created by introduction of chemicals into the atmosphere during the experiment.