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Comment by Mithrandir | Hacker News Reader

I took a screenshot of one of the videos: http://i.imgur.com/nppgVPG.jpg

Perhaps Iridium refers to the Iridium satellite constellation (https://en.wikipedia.org/wiki/Iridium_satellite_constellatio...) (Edit: or maybe one of their products http://www.iridium.com/Products.aspx) and "SBD service" refers to something like this: http://www.iridium.com/products/IridiumSBD.aspx?section=supp... ?

Edit 2: Perhaps they were tracking the balloon?

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Iridium is the ultimate backup connectivity (for balloon control, not for data). It's very slow and very expensive, but works everywhere and requires a small antenna.

It looks like they're using the short burst data (SBD) service to 'control' the balloons.

  (Email) : SENT : B1 > power on rocket
  RESPONSE : B0 > SUCCESS(0)
  RESPONSE : B1 > SUCCESS(0)

It would likely not use the Iridium satellites, they are bandwidth constrained, quite slow (due to roundtrip distance) and very expensive. It also wouldn't be offering much advantage over connecting to the satellite directly asides from that I guess you could connect via normal wi-fi perhaps as opposed to needing a satellite receiver on the ground. Perhaps they could be using one of their products though. At least, that's what my experience working with Iridium satellite systems would lead me to believe.

Looking at the solar information (on the left), power doesn't look too good.

Would these balloons still work during the night? Would they need to stay in the day? Would that even be possible, given the speed of the wind?

It says on the site that they charge during the day and run off batteries at night.

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