Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I can't find a reference of a working stratospheric balloon mounted with a compressor to control its altitude. Is there a big physical difficulty (such as compressor weight/power ratio, or power source availability) which prevents this, or just no one as an interest in it ?

share|cite|improve this question

closed as off-topic by Brandon Enright, BMS, John Rennie, Danu, ACuriousMind Oct 27 '14 at 10:04

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "This question appears to be about engineering, which is the application of scientific knowledge to construct a solution to solve a specific problem. As such, it is off topic for this site, which deals with the science, whether theoretical or experimental, of how the natural world works. For more information, see this meta post." – Brandon Enright, BMS, John Rennie, Danu, ACuriousMind
If this question can be reworded to fit the rules in the help center, please edit the question.

Frankly I don't see this as a physics question. I'm pretty sure that you are already on the trail of the engineering answer. – dmckee Apr 22 '12 at 2:44

The pump and power supply would add a great deal to the weight and cost compared to simply dumping the helium. And when it did descend how would you control where it landed? Most of the earth isn't very accesible.

Most stratospheric balloons are for weather observations - it's much easier to just dispose of them and their payload when they pass out of the region you are itnerested in rather than trying to retrieve them

share|cite|improve this answer

They are compressing their helium to descend.

When they descend (if they descend) they are going to a lower altitude with higher atmospheric pressure, which compresses the helium, so the balloon has smaller volume.

Helium balloons control their rate of ascent/descent by releasing ballast or valving off gas. Either way, the bouyancy of the helium in the envelope just balances the weight of the payload. As they go to a higher altitude where the air is thinner and has less pressure, the helium expands until it displaces the same weight of air as it did before. Same thing when it goes down.

Here is Felix Baumgartner's balloon when it's lifting off. Notice how little of the "bag" is occupied:

enter image description here

And here it is at 36km altitude:

enter image description here

share|cite|improve this answer

Check paragraphs 5-7 for a possible the compression option.

share|cite|improve this answer
Hi Tim, we generally expect answers to stand alone. Can you please update your answer to include a sketch of the information included in the link? – Brandon Enright Oct 27 '14 at 4:02

Not the answer you're looking for? Browse other questions tagged or ask your own question.