Misunderstood “photophoresis” effect could loft metal sheets to exosphere

Light and lifting

The researchers then built a few nanocard leaves to test the release of their model. Real products, mainly made of chrome, aluminum and aluminum oxide, were incredibly light, weighing only a gram for a square meter of material. When lit by a laser or white LED, they have generated a measurable force on a test device, provided that the atmosphere is maintained rare enough. With an exposure equivalent to sunlight, the device generated more than it weighed.

It is a very beautiful demonstration that we can take a physical effect and relatively obscure and weak design devices which can levitate in the upper atmosphere, supplied by nothing more than sunlight – which is rather cool.

But researchers have a goal beyond that. The Mesopher turns out to be a really difficult part of the atmosphere to study. It is not dense enough to support balloons or planes, but he still has enough gas to do a quick job of all satellites. The researchers therefore really want to transform one of these devices into an airplane that carries instruments. Unfortunately, this would mean the addition of the structural components necessary to contain instruments, as well as the instruments themselves. And even in the mesosphere, where the elevator is optimal, these things do not generate much from the elevator.

In addition, there is the problem of bringing them to them, since they will not generate enough elevator in the lower atmosphere, so they will have to be transported in the upper stratosphere by something else and then be released gently so as not to damage their fragile structure. And then, unless you can during the polar summer, they will probably come back at night.

None of this means that it is an impossible dream. But there are certainly a lot of very large obstacles between work and practical applications on Earth – much less on Mars, where the authors suggest that the system could also be used to explore the mesosphere. But even if it does not end up being realistic, it is still a little fairly neat physics.