NSL-72

Morning Star

NSL-72 flew the early morning of May 19, 2019. Paul L's goal was to test some low light camera software and to see if "cool" images could be captured of the NC coast with sunrise. The weather forecast promised clear skies with an almost full moon setting. The projected flight path indicated an especially unusual figure-eight as the gentle winds resulted in a landing zone very close to the launch site. The sun rose that day at 0609EDT -- as seen on the ground. At altitude, the sun would rise 40+ minutes sooner. This required a launch before 0430EDT (yikes).

Paul's flight rig for the 2019 Burlington Maker Faire still sat around, since bad weather scrubbed that flight. So he reprogrammed the cameras, charged up batteries, and prepped for launch. The payload was a small plastic (lunch meat) container filled with black foam -- The same well-worn rig from NSL-61, 63, and 66! It contained an AP510 APRS tracker with large battery; a Mate-808 camera, connected to the same battery; and a 808 #16 camera with a separate 2000mAh battery. With OHCRAP spool; orange ribbon and parachute, the entire system came to just 250g.

Around 4am, Paul quietly inflated a 600g cell to 750g neck lift with H₂. A very slow and calm launch followed at 0413EDT.

Moments after launch, the sky started to fill with thin clouds. Previously the sky was clear with stars and a very bright, almost-full moon. But suddenly wisps of clouds appeared. Then the wisps grew into sheets. The on-board video captured much of this as the payload climbed.

Above 10km, the eastern horizon began to show signs of glow. Sadly, the view towards the ocean became obstructed by growing clouds. The earth's shadow crept from east to west, making a dramatic dark arc in the sky.

The flight ascended over 20km and drifted back over the Apex, NC launch site. A sleepy Paul waited below and watched from his driveway. Having been just moments away from personally witnessing burst on NSL-71, he kept his eye on the bright white dot as is circled overhead. The sky grew lighter. The balloon barely moved and it seemed that it would take forever to burst. Only the discomfort of laying on his driveway for 30 minutes kept Paul awake. He was rewarded when, at almost 35km, the white dot disappeared before his eyes. Max recorded altitude 34779.4m (114,105ft).

The slow and squiggly figure-eight of the flight path meant that the payload would not fall far from the launch site. The payload was expected to land just north, but during the last 6 minutes of decent, balloon remains fouled the parachute and it came down faster.
[Paul's note: "Kaymont 600g cells have a thick, small diameter neck. For some reason, these balloons seem to stay mostly intact after burst and can foul chutes. Hwoyee cells, on the other hand, tend to entirely shred."]

As a result of the fouled parachute, the payload landed short... and quickly. The impact dislodged the ribbon cable on the Mate-808 and its software crashed, corrupting the final video file. At least recovery was a piece of cake! No one was on the road early on a Sunday morning, otherwise the payload may have been run over.

The small payload fell to -12C inside on this long flight before the rising sun started started adding warmth.

The modified 808 #16 did not show any improvement in nighttime video quality.

The Mate-808 camera showed a couple of interesting video artifacts. First, when looking directly at the sun, the chip must have some sort of numeric rollover, as the center of the sun appears as a black disk. Secondly, when brightly lit at an angle, a reflected image of the chip's substrate becomes visible -- like circuit board cataracts.