NSL-63

On Saturday, April 28th 2018, we flew NSL-63 at our annual participation in the Burlington Maker Faire. As in previous years, we operated a booth at the Faire and held a public launch at Noon. Chris G. and Tim W. were launch/chase crew while Paul, Matthew, and Sarah L. staffed the "Mission Control" booth.

The payload was very similar to NSL-61. It consisted of two small payload boxes and parachute on a 9m ribbon, all totaling 400g. A 600g balloon was filled to just over 2kg of neck lift. The upper payload box was a Pi-in-the-sky-like LoRa tracker/camera system. The lower payload box held an AP510 APRS tracker and an 808 #16 video camera, each with their own batteries.

The weather was beautiful and the jet stream let up just enough to keep our payload in North Carolina. The northeast track would take it dangerously close to Kerr Lake, so we added extra lifting gas to make it burst early. It was a bit windy during fill, but thankfully was calm enough for us to be filmed by drones from AMG's Autonomous Vehicle Interest Group.

After launch, the chase crew headed out with their Pi LoRa gateway. Live images were routed through the chase car and on to the Habhub.org website. This allowed the visitors to our Maker booth to watch not only the flight track, but the scenery.

As in NSL-61, the flight was very gusty/violent. The lightweight payload was effortlessly tossed end-over-end and around the balloon. At times, the payload at the end of the line was snapped like the end of a whip. This caused the emergency spool of string (Outside Hung Compact Rain-Activated Pull-down) to deploy prematurely, so soon the payload had an additional 15m of string whipping behind.

At 27km up, the lower payload took an extreme jolt and the APRS antenna was sheared completely off. Suddenly, the payload telemetry fell silent back at Mission Control.

This happened during the leg of the flight that took the payload the furthest away from the chase crew below -- The secondary Raspberry Pi tracker was out of radio range. All the chase crew could do is continue up Interstate 85 towards the expected landing area. We kept our fingers crossed that the payload was still intact and that we would regain telemetry. Unbeknownst to the world, the payload continued up towards 30km and burst.

After a tense 15 minutes, the payload and chase crew converged to within 32km (20 miles) of each other. Raspberry Pi radio data was reacquired and live images started to come in. There was a cheer from the crowd back at the Maker Faire.

The on-board predicted landing site telemetry was blank though. It seems that the AA battery pack for the Raspberry Pi took a jolt at burst and this caused the Pi to reboot and lose all of the gathered information for its predicted landing code. Changes made after NSL-61 were apparently not enough (need a bigger capacitor).

The payload drifted in for landing. Without the weight of the lost antenna and spool, it floated in a bit further than expected and landed very close to Kerr Lake. The chase crew was in the neighborhood and kept an eye out for the small payload, but did not spot it coming down. It landed in trees about 200m from the road.

Back at the Maker Faire, visitors spied the small images from the payload and tried to guess just how far up a pine tree it was. They could definitely tell that it was stuck in a pine tree.

Tim W. was prepared though, he lobbed a line up over the payload and was able to pull it down!