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Line 20: − In August, [[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.+ + − Thus, it was immediately decided that a repeat launch would be attempted, with nearly the exact same configurations, except for the addition of a SPOT Trace and strengthening of RockBlock connections. Since a repeat build would require little additional design work, it was decided that the repeat launch would be attempted on the evening of '''August 6, 2019''' from Pigeon Point.+ − − As simulations from Pigeon Point showed the trajectory heading northeast over the Bay Area, it was decided on July 30 to request permission to launch from Garin Regional Park in Hayward, CA instead. That same day, avionics work began and was concluded on August 1. Due to the anticipated short duration of the flight, it was decided to reduce the power bank from 18 to 9 batteries. On July 31, the launch was moved to '''August 5, 2019''', and on August 2 the new launch site was rejected. − − The construction of the ZPB and final payload assembly occurred on August 4. It was generally agreed that the quality of the balloon was inferior to that of the first attempt due to several reasons.
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==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.
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]].
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.
==Configuration==
==Configuration==