So many interesting details even in the first post…
• Some GPS modules are crippled to not work very high and very fast so they can't be used on ballistic missiles.
• "Rise time" is an issue with balloons. You want to hurry up to your burst altitude to stay warm and not drift too far. I suppose aerodynamic shapes are out since it has to be able to expand hugely as it rises.
Yes, the rules (http://en.wikipedia.org/wiki/CoCom) dictate that the GPS should cut out if the device exceeds a speed of 1000kts AND an altitude 60,000 feet.
A lot of GPS units wrongly interpret these limits as being 1000kts OR 60,000 ft, and so aren't suitable for high-altitude ballooning.
Of course, it's a silly restriction because if you've got enough money to build a ballistic missile, you've probably got enough to build your own GPS receiver (CU Spaceflight have built a software GPS receiver themselves).
I'm glad that you enjoyed that. I was using the blog post in part to document what I had found. Hopefully, others will found the information useful.
I went to a balloon launch yesterday in Cambridge and the guys there were great. Very helpful and explained many little things that I don't have time to blog about.
• Some GPS modules are crippled to not work very high and very fast so they can't be used on ballistic missiles.
• "Rise time" is an issue with balloons. You want to hurry up to your burst altitude to stay warm and not drift too far. I suppose aerodynamic shapes are out since it has to be able to expand hugely as it rises.
… ah, details.