Dave, Mike, and Toni from Sparkfun Electronics came all the way down to our launch site in Monument to launch their balloon with the EDGE3 flight, and we're thrilled that they did! The result was that we were able to participate in the highest flight that any of us have been directly involved in, and perhaps the 17th highest HAB flight recorded!  To put their max altitude in perspective, their payload made it 2,000 feet higher than the Red Bull Stratos mission did.  How did they do it?  There was some luck, to be sure, but it didn't hurt that their entire payload string weighed about 3 pounds, and the lift measured at the neck of the balloon (a 1600g envelope) was slightly less than 5 pounds.  You'll notice in the flight video that their balloon appears underinflated... because it is.

One of the unintended consequences of the underinflation of the 1600g balloon was that their payload actually hovered for about 10 minutes prior to burst.  This kind of behavior has been seen before, but it's pretty rare: the latex balloon reaches its elastic limit and has just enough tensile strength to contain the lift gas.  Essentially, a normal weather balloon becomes a superpressure balloon.  Fortunately for the Sparkfun team, this float phase didn't last too long - the last balloon that we know of that did this crossed the Atlantic Ocean from California.