Photophoretic Levitation of Discs

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Sustained flight in Earth's mesosphere, located 50-80 km above sea level, poses challenges for aircraft, balloons, and rockets due to the high altitude. Similar conditions are encountered at lower altitudes on Mars, requiring specific adaptations. Access to these regions is crucial for climate change research and a better understanding of Mars.

Our research group proposes the use of photophoretic (light-driven) levitation to enable the deployment of sensors at these altitudes. To achieve this, we utilize mylar discs with a thickness of 0.5 microns, coated with a carbon nanotube (CNT) solution which undergo alumina deposition (ALD) to maintain stiffness. The samples are then tested on a flat steel mesh, known as a launch pad, within a vacuum chamber. 

In order to understand how accurately our experiments reflect real world conditions, I co-led an examination into the impact of the ground-effect on the performance of our samples in closed environments when using a launch pad.

In order to validate our experimental system, I developed an alternative launchpad to better simulate midair conditions. In contrast to the steel mesh employed in earlier experiments, I designed and manufactured a structure made of three J-shaped (candy cane-shaped) steel mesh wire grounded and positioned in an aluminum ring.

Variables observed to better understand the ground effect experienced by samples and its impacts on results include:

• Diameter of wire mesh
• Open area of wire mesh
• Diameter of J-shaped wire
• Diameter of levitated samples

Our results indicated that the ground effect interactions between the samples and launchpads were non-negligible. As such, we validated that my J-shaped cane launchpad should be used to produce the most accurate performance data for CNT-mylar samples.