NSL-73

NSL-73 flew on the morning of 26 May, 2019. This research flight tested engineering procedures for exposing biologic samples to the extremes of near space.

Aurora T. and Paul L. met at Bond Park in Cary, NC and constructed a chain of payloads. Aurora's payload contained yeast samples for the test and the T-Beam LoRa tracker from NSL-71.

About 2m beneath that dangled Paul's payload -- the simple box from NSL-72 with only the AP510 APRS tracker and the Mate-808 camera. It took about an hour to build the payloads and develop a launch plan. The entire flight train massed less than 600g. For a typical 30km flight, a 600g cell was filled with H₂ to about 1550g neck lift. At 1008EDT, with the boxes secured and trackers tested, the flight was sent aloft.

Being a hot and humid Memorial Day weekend, the on-board images showed a thick layer of haze across North Carolina.

The team then headed out in two chase cars. The 2.5 hour flight path carried the payload southeast towards Smithfield, NC. Being only an hour away by car, this gave the chase crews ample time to stop for gas, snacks, and to swap out launch equipment for recovery equipment.

The on-board video showed its lightweight bottom payload being tossed about constantly -- not pleasant to watch. Both trackers, meanwhile, sent telemetry down to the chase cars, informing them of position and the changing temperature of the sample container.

At 31km, the balloon burst, providing us with some fun still images:

Maximum altitude recorded by trackers: 31263m (102,569 feet)

The flight descended as expected. As seen in the above images, its 600g Hwoyee cell shattered almost completely, so the parachute did not foul. As the Habhub live course predictions updated, the chase cars converged on the landing neighborhood. Paul guessed the wrong street and was about a block away when the payload landed. Paul and Matthew L. did hear dog barking from over a treeline. Minutes later, they made it to the correct street and found the dog. This led Matthew to spot the nearby payload. Amazingly it had missed a large stand of trees -- and a swimming pool -- landing between them!

Above is data from LoRa receivers

From Paul L: "We don't have a high precision data-set of this flight due to a couple of mistakes I made. The AP510 tracker was flown without its microSD card -- I put the card in one AP510 and ended up flying the other. Similarly, I had planned to fly a 915MHz T-Beam and had it reset for flight. I ended up flying the 433MHz T-Beam and didn't reset the on-board flash. It still was full from NSL-71 and could not record any more data in its limited flash. Doah!"