Chinese "weather" balloon shoot-down over US

[hutchphd]

Do they pack those in powder when they fold them up? I would think there might be electrostatic sticking issues upon launch.....(it is a good question 'cause I sure don't know)

 

[sophiecentaur]

Do they pack those in powder when they fold them up? I would think there might be electrostatic sticking issues upon launch.....(it is a good question 'cause I sure don't know)

You are referring to the "something inside" comment. Perhaps it's condensation as the pressure (albeit very low) changes. Like a short lived con trail.

 

[hutchphd]

Is there any way ice could have condensed on the interior on the way up? Seems unlikely.

 

[sophiecentaur]

Not in the interior because they would (presumably) use the purest lift gas available (at the price). I was thinking of the internal gas cooling as it burst. I wonder about the proportion of H2O vapour at that height. It could be higher and probably more stable than it is, lower down.

Which makes me wonder about the lift gas used. H2 has better lifting than He and safety is less of an issue than with passenger craft. Also, it must be a lot cheaper.

 

[Vanadium 50]

H2 has better lifting than He

Yeah, but only by 7-8%.

It has the advantage and disadvantage of going boom. If you want to destroy the evidence, it's easy. The political repercussions of gaving something go boom over someone else's country might be less desirable and likely difficult to predict.

 

[sophiecentaur]

Oh, I didn’t realise the marginal lift advantage. But He is getting more and more relatively costly.
Plus you can’t get an H balloon to ‘explode’. H will burn rapidly in contact with air as there’s only O2 outside the bag. Wooof is not Bang. I doubt if you’d hear much at 10km distance.
No fun being up there though. A gondola with pyro cable disconnect and a delayed opening chute could land you safely. And think of the money you save.