March 2017 – NCL set out to Alaska with the wild ambition of recording video of the northern lights, for the first time in known history, from a high altitude balloon. After many local test flights in California, several design iterations, and much planning, we headed north.
We spent a total of two and half weeks in Fairbanks. The first week was spent doing reconnaissance and testing equipment. Neither our flight cameras or us had ever seen the northern lights, so we had to make sure we had our settings right. We were fortunate to have high auroral activity (kp’s of 4 to 6) and clear skies, giving rise to some of the most stunning views of our lives.
Since we were up all night chasing aurorae, we used what little daylight hours we had while awake to scout out and plan launch and landing locations that were accessible by road, at least as best we could. It gets rural fast outside of Fairbanks itself, but the winds were (at least somewhat) in our favor.
We flew a total of 3 balloon flights over Fairbanks, two during the day, and one at night to capture video of the aurora.
To capture the relatively faint aurora borealis at night on video, we needed a low-light capable camera system. We decided on the Sony a7S: a low weight, full-frame mirrorless camera with incredible low light sensitivity. Before the Alaska mission, we decided to flight test the Sony a7S performance in the stratosphere. In 2015 and 2016, we launched separate high-altitude balloon missions, testing the camera’s capability. After stellar results, we decided to continue baseline it as the flight camera to capture the aurora. Along with the camera, we used the following supporting equipment to make up the camera payload:
Sony a7S (Mark I)
Rokinon 24mm, f/1.4 lens
Atomos NInja Flame 4K Recorder
Varavon External Battery
Neat Video (software plugin)
The complexity of this mission in the harsh Alaska conditions called for some custom hardware. This began with the NCL Balloon Integrated Re-programmable Computer (BRIC) – Mark II. The BRIC consists of an Arduino MEGA which runs our custom flight management software. We had a custom Printed Circuit Board (PCB) fabricated to allow for ease of integration with other components including a GPS unit, radio telemetry link, barometric altitude sensor, and 8 thermistors (temperature sensors). The GPS helps us determine position, the radio allows us to track the payload in real time, and the thermistors give feedback for our electric heating system needed to keep everything from freezing in the harsh -50 deg C (-58 deg F) high altitude environment.
In addition to capturing video of the northern lights, we collected radiation measurements during the flight. For more on the science of the aurora and these radiation measurements, check out this in-depth article by NCL’s Ashish Goel.
Our successful night flight can be seen on YouTube here.