1. (Atmospheric spectra from “am” model, thanks to Stevie Bergman and Bill Jones) https://www.cfa.harvard.edu/~spaine/am/

2. (Atmospheric spectra from “am” model, thanks to Stevie Bergman and Bill Jones) https://www.cfa.harvard.edu/~spaine/am/

3. “Superpressure” balloon => long duration even with day/night cycles. Potentially ~100 day flights from Antarctica or New Zealand. Less payload mass, ~3500lbs (vs. ~5000) Ultra Long Duration Ballooning Image: NASA/CSBF 32 day flight from New Zealand, March/April 2015