Every year the Global Space Ballooning Challenge (GSBC) connects teams from all around the world to send as many high altitude balloons into space simultaneously as they can. Using large weather balloons, cameras and sensors are sent to the edge of space in order to collect data and amazing aerial photos. According to the GSBC site, “The fundamental goal of the GSBC is to build a community where everyone can learn from each other and build on each other’s accomplishments, with a focus on education and technological development.”
This year the Balloongineers team based out of Issaquah, WA got their balloon up to a height of 31km. Kevin Hubbard, the self-proclaimed greenhorn of the team and a former IBM employee whose work included the AS/400, worked on the Balloongineers’ electronics package and documented the whole adventure on his blog.
“I spent 6 challenging weekends non stop doing Hardware and Software development and Test to make the launch date. HAB1 electronics are built from a high altitude flight ready uBlox GPS unit, a 2-way Iridium RockBLOCK satellite communication modem, 1/2 a dozen custom circuits boards design and built using CopperConnection and OSH-Park, a fully custom FPGA “Lizard Brain” design and a RaspberryPi Linux computer running a custom Flight and Communication program written in Python. All these pieces had to work together – all the time – with built in fault tolerance – all in 6 weeks for the contest opening.”
With such a tight deadline there was bound to be some issues, but none were more last minute than this one:
“Low pressure gas expert and valve designer Dr.P and I are now both waiting for the now fully inflated balloon to attach to the valve assembly (which is connected to the Flight Computer capsule via a 3 wire servo connection ). As the 4″ hose clamp is tightened by the fuel specialists and balloon handlers – we gasp in horror ( caught on video verbally and by the look of terror on my face here ) as we realize the small 3 pin 0.100″ pitch SIP connector connecting the Flight Computer to the Valve servo assembly is not only disconnected – but the pins are bent. SIP connectors are great – I use them all the time – but they really don’t like to be bent. These were dangerously close to the hose clamp. Bend SIPs once – maybe, bend them twice – and they break off. Do we abort the launch? Is there time to solder a new SIP connector on the leads running 12″ to the flight computer? No – the balloon is filled and ready to go. The balloon handlers in their special balloon protecting gloves are now responsible for keeping the balloon untouched from any foreign objects before flight – it just is not feasible to abort this late in launch with the balloon already inflated.”
With no time to lose or retest their valve assembly, Hubbard fixes the pins as best he can with a pair of plumbers pliers and some duct tape and the team hopes for the best. The balloon is released and begins its flight. The first three hours of the flight goes smoothly, with detailed telemetry coming in every 10 – 15 minutes. At about 80k feet above sea level, the Balloongineers get some disturbing news: Their balloon is going much faster than it should be (if it goes too high it will burst) and the scheduled 5 second bursts of venting haven’t been reported to ground control. They send a message to do a long vent in an attempt to stall the ascent and get the balloon to hover around 90k feet, but the balloon continues to rise.
Their balloon sends a message from a little over 100k feet of altitude. That’s the last message they hear from it that night and the next day they don’t hear from it at all. Then, just when Hubbard begins organizing a crowdfunding campaign to replace the Iridium RockBLOCK modem of the balloon’s electronics package, he gets a message. Their high altitude balloon is waiting for them 300 feet off the ground in nearby Mill Creek.
“107 Meters – I’m picturing in my head our bird on the ground on a nice grassy 300 foot hill surely – nope – not even – after a reasonable in country boots on the ground search area ( Terry also brought 3 pairs of rubber galoshes ) we located our little balloon on top of a tree. A REALLY TALL tree.”
No one died during the recovery process, but they could have… it was a very, very tall tree. To read more details about the Balloongineers design, their balloon’s flight and recovery, and the post-flight electronics assessment, read Kevin Hubbard’s full write up on his blog.