Cool [Q] Android device in Stratosphere


In a nutshell I want to tie an Android device to a weather balloon and send it up 100 000 Feet or approx. 30 km.

What I need is the following:

-) A GPS Tracking software
-) A video cam app for recording the entire mission

I found several suitable Location Tracker Apps and decided to use the "Call, GPS, SMS Tracker". So that's covered.

However I'm having a suprisingly difficult time to find a video camera app that can record video while the screen is turned off. Having the screen turned off is neccessary to conserve power, because the whole mission will take approx. 3 to 4 hours.

Does anybody know of an App that can record video with the screen turned off?