{"id":263,"date":"2010-09-26T22:32:39","date_gmt":"2010-09-27T02:32:39","guid":{"rendered":"http:\/\/blog.alanporter.com\/?p=263"},"modified":"2010-09-26T22:32:39","modified_gmt":"2010-09-27T02:32:39","slug":"ncnearspace-nsl3","status":"publish","type":"post","link":"https:\/\/alanporter.com\/blog\/2010\/09\/26\/ncnearspace-nsl3\/","title":{"rendered":"High-Altitude Balloon Launch (NSL-3)"},"content":{"rendered":"

\"\"<\/a>About a month ago, some friends found out about a contest called “Hackerspaces in Space”, where the object was to take a picture of the curvature of the Earth, with black sky over a band of blue. \u00a0This kind of picture can only be taken from space… or from “near space”, above about 65,000 feet. \u00a0That’s about twice as high as most passenger airliners fly! \u00a0My friends quickly got together, declared themselves “NCNearSpace<\/a>“, and researched everything from balloon physics to wind models to FAA regulations. \u00a0Three weeks later, they launched two helium balloons up to about 80,000 feet. \u00a0When they retrieved the capsules, they were rewarded with stunning photos.<\/p>\n

The group was encouraged by their successes, and they sought out help in their next attempt, which would aim for a much higher altitude, hopefully 120,000 feet. \u00a0This would require a much larger balloon. \u00a0However, the team found that their earlier research had prepared them for this next launch — not much had changed, other than the sizes of the balloon and capsule.<\/p>\n

One area that really needed some work was the recording and dissemination of position data. \u00a0The first launch (dubbed “NSL-1”) was supposed to use a small GPS and a ham radio transmitter in a system called APRS. \u00a0This system worked for a little while, but mysteriously stopped transmitting after 10,000 feet. \u00a0They never heard from NSL-1’s transmitter again. \u00a0Feeling rather bummed at the loss of their capsule, they hastily assembled a second launch using left-over parts and a SPOT<\/a> GPS transceiver, a commercial unit and subscription service which is normally used by sailors, hikers, and mountain climbers. This second launch, NSL-2, did surprisingly well, considering its humble beginnings. \u00a0The were able to follow the position using the SPOT web site, and they retrieved NSL-2 before the sun set. \u00a0(About a week later, a farmer found NSL-1 and called the phone number, much to the delight of the team).<\/p>\n

A week before the launch of NSL-3<\/strong>, I took a look at some scripts that had been used to retrieve the position data from the SPOT web site. \u00a0Since the earlier chases had led the team through some very rural country areas, they found that it was not too easy to access the SPOT web site from the road. \u00a0Furthermore, the SPOT web map required a full-sized PC with some pretty fancy web browser magic installed. \u00a0It would be nice to get this information on a mobile phone. \u00a0I did a little bit of hacking, and soon, I had a script that would:<\/p>\n