Mohsen Azadi, the paper’s lead author, wields a scalpel in preparation for the photophoretic experiment. (Image Credit: Eric Sucar, University Communications)
Engineers at the University of Pennsylvania have successfully used light to levitate two small plastic plates. The team believes this concept could be applied to future spacecraft, allowing them to levitate in the mesosphere using sunlight. These could also be used for space exploration and to study the weather. NASA already has its sights set on this tech for future Mars missions.
The team has been exploring light levitation for awhile now. However, the concept of moving objects with light, also called light-induced flow, has been around for some time. In the past, researchers made aerosol compounds hover and sort tiny particles. The same technique has never been used with larger objects that can be handled in the real world.
In their experiment, the team used two six-millimeter diameter plates that have a 500-nanometer-thin film of Mylar on the top surface. The bottom consists of a scratchy coating made of carbon nanotubes that heats up when a set of bright LED lights, which imitate the sun’s intensity, beam on it. This heat then causes the air particles under the plates to charge, resulting in its levitation. The team experimented with the new tech in a chamber designed to imitate the upper atmosphere’s low-pressure environment.
Even though the experiment occurred in a test chamber, the team developed a theoretical model to predict what happens with different-sized plates. They believe that it could levitate a plate outfitted with environmental sensors 50 miles into the air.
Therefore, this presents scientists with a unique opportunity: exploring the mesosphere. They would be able to collect important measurements of carbon dioxide, which are needed to monitor climate change. Researchers think that by using light-based levitation technology, crafts could carry significant payloads, such as scientific instruments. Payloads could weigh 10 milligrams, which is suitable enough to send either a small carbon dioxide or dust sensor into the mesosphere.
The whole idea here is still theoretical. The team needs to overcome many obstacles before applying them in the real world. More experiments need to be conducted so that a craft could carry a payload larger than 10 milligrams. Researchers could also make it so that the craft could be steered and controlled when it’s in the mesosphere.
Earth’s atmosphere has many complex, diverse layers. One of which, the mesosphere, is located 31 to 53 miles above the Earth and is challenging to study. This layer burns up satellites but can’t provide lift for a satellite or weather balloon.
The mesosphere provides insight into climate change and ozone damage. Applications for the light-levitation tech could be used on our neighboring planet as well. NASA has a keen interest in this light-levitation technology because Mars’ atmosphere is identical to the mesosphere. Equipping a rover with this new tech could allow the craft to collect additional data about the red planet.
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