I did this short animation for the Austrian Space Forum.
It shows a "weather2- ballon in the heigth of about 35-40km (which is quite high for such a ballon). At this heigth the conditions of the atmosphere are compareable to the martian atmosphere. This flight is part of the Polares Project, more infos: www.polares.org
The clip is not a sientific simulation, more a visualization (the real balloon will have a larger diameter at this height and no logos…). Parts of it will probably being transmitted on Austrian TV.
A YouTube Low Quality Version:
http://www.youtube.com/watch?v=8bE-OOAMJFc
A higher quality version can be found here (at the bottom of the page under multimedia):
http://www.polares.org/cms/paimages.phtml
Very nice, the renderings are not that realistic but I think they perfectly match the content and stile of the animation. Good job.