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'''SSI-92''' (project designation '''CY-6''') was the sixth launch of [[Cycloon|Project Cycloon]] on October 5, 2019. It was the first interstate Cycloon flight, the first launch of a poly tubing ZPB, and the first ZPB flight for which telemetry at equilibrium and descent was acquired since [[SSI-20]]. This enabled the acquisition of valuable thermal data and verification of equilibrium altitude predictions.

'''SSI-92''' (project designation '''CY-6''') was the sixth launch of [[Cycloon|Project Cycloon]] on October 5, 2019. It was the first interstate Cycloon flight, the first launch of a poly tubing ZPB, and the first ZPB flight for which telemetry at equilibrium and descent was acquired since [[SSI-20]]. This enabled the acquisition of valuable thermal data and verification of equilibrium altitude predictions. Continuing a trend, the payload was lighter still than that of its predecessor, [[SSI-91]].  

==Project context==

==Project context==

[[SSI-91]] was a milestone in realizing flights with in-house manufactured ZPBs, yet due to unexpected termination no data on the equilibrium altitude and descent characteristics were obtained, thus failing to fulfill one of the major objectives of that flight. Meanwhile, a candid assessment of the ZPB manufacturing process proved discouraging. In mid to late August, a new manufacturing technique was devised based on commercially available polyethylene tubing, which promised to be far more durable and scalable. (The altitude limitations were deemed acceptable for the time being). Orders for commercial tubing were placed, set to arrive in September. In light of these developments, a third summer ZPB launch which had been planned for the weekend of September 1 was cancelled.

[[SSI-91]] was a milestone in realizing flights with in-house manufactured ZPBs, yet due to unexpected termination no data on the equilibrium altitude and descent characteristics were obtained, thus failing to fulfill one of the major objectives of that flight. Meanwhile, a candid assessment of the ZPB manufacturing process proved discouraging. In mid to late August, a new manufacturing technique was devised based on commercially available polyethylene tubing, which promised to be far more durable and scalable. (The altitude limitations were deemed acceptable for the time being). Orders for commercial tubing were placed, set to arrive in September. In light of these developments, a third summer ZPB launch which had been planned for the weekend of September 1 was cancelled.

With the end of the summer, onboarding approached, and it was hoped to do a Cycloon demonstration launch very near the beginning of the year, on '''October 5, 2019'''. Ideally this would be ballast-controlled, collecting data and paving the way for a fully controlled launch in the middle of the quarter. It was also hoped to do this launch from Pigeon Point, but by September 23, wind forecasts proved unfavorable. Additionally, momentarily it was planned to launch two ballast controlled balloons (as a means of forcing Cycloon to self-manufacture a ballast mechanism), but as 3D printing attempts in the last week of September failed, this too was discarded. Nevertheless, a significant worksession on September 29 produced two balloons and two sets of avionics (one new, one recovered from [[SSI-91]].

With the end of the summer, onboarding approached, and it was hoped to do a Cycloon demonstration launch very near the beginning of the year, on '''October 5, 2019'''. Ideally this would be ballast-controlled, collecting data and paving the way for a fully controlled launch in the middle of the quarter. It was also hoped to do this launch from Pigeon Point, but by September 23, wind forecasts proved unfavorable. Additionally, momentarily it was planned to launch two ballast controlled balloons (as a means of forcing Cycloon to self-manufacture a ballast mechanism), but as 3D printing attempts in the last week of September failed, it was decided to fly only one standard (non-controlled) ZPB. Nevertheless, a significant worksession on September 29 produced two balloons and two sets of avionics (one new, one recovered from [[SSI-91]].

Relatively near the flight, demands for an improved cutdown mechanism intensified. Amidst an absence of nichrome, a novel cutdown mechanism involving two ematches and a socket was devised, implemented, and tested the night of October 4.

Relatively close to the day of the launch, demands for an improved cutdown mechanism intensified. Amidst an absence of nichrome, a novel cutdown mechanism involving two ematches and a socket was devised, implemented, and tested the night of October 4.

==Configuration==

==Configuration==

'''Balloon''': 0.3 mil polyethylene, paper bag topology, width 1.8 m, length 7 m, volume approximately 6 cubic meters. Total mass 0.26 kg with fill tube (PVC of length approximately 12 inches and diameter 1/2 inch).

'''Balloon''': 0.8 mil polyethylene tubing, paper bag topology, width 2.5 m, length 10 m, volume approximately 17.5 cubic meters. Total mass 1 kg with fill tube (PVC of length approximately 12 inches and diameter 1/2 inch).

'''Avionics''': TinyGPS, Teensy 3.2 transmitting at adjustable intervals over Rockblock. SPOT Trace. Attempts to interface this Teensy with a BMP 280 were universally unsuccessful. This set of avionics was finished from the incomplete second set made for [[SSI-87|CY-3]].

'''Avionics''': TinyGPS, Teensy 3.2, BMP 280 transmitting at adjustable intervals over Rockblock. A SPOT Trace was accidentally omitted. This set of avionics was recovered [[SSI-91|CY-5]]. Controlled novel cutdown mechanism.

'''Power''': 9 L91 lithium AA batteries. Resistive heater running on single L91 battery.

'''Power''': 9 L91 lithium AA batteries. 3 L91 lithium AA batteries on cutdown.

'''Payload''': Styrofoam enclosure. Mass 0.62 kg.

'''Payload''': Styrofoam enclosure. Mass 0.55 kg

'''Mass budget''': 0.88 kg total.

'''Mass budget''': 1.57 kg total.

==Flight synopsis==

==Flight synopsis==