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Ultimately it's about the ballistic coefficient. You want high mass, low cross-sectional area, and low drag coefficient (Cd). With propulsion for station-keeping, it's challenging to capture the VLEO benefits with a regular cubesat. That said, there are VLEO architectures different than Clarity that make sense for other mission areas.

Yes it's a big contributor. The atmosphere in VLEO behaves as free molecular flow instead of a continuous fluid.

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Cue the ultimate low orbit satellite

> It is undesirable to have a definition that will change with improving technology, so one might argue that the correct way to define space is to pick the lowest altitude at which any satellite can remain in orbit, and thus the lowest ballistic coefficent possible should be adopted - a ten-meter-diameter solid sphere of pure osmium, perhaps, which would have B of 8×10^−6 m^2/kg and an effective Karman line of z(-4) at the tropopause

from https://arxiv.org/abs/1807.07894

Assuming I did the math right such a satellite would only run $265 million USD for the materials (launch costs for an object of ~9k kg left as an exercise for the reader). That's far more affordable than I had expected. Amusing thought.

That would make a hell of a bang when it eventually deorbits.

Why no fold mirror then?

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