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Designations CY-7
Launch date October 26, 2019, 10:14 PDT
Launch site Brigantino Park, Hollister, CA
Launch coordinates 36.849, -121.433
Flight duration 4h:04m
Flight length 202 km
Flight profile Folded zero pressure w/ ballast control
Landing time October 27, 2019, 14:18 PDT
Landing site 9 km SW of Tulare, Tulare County, CA
Landing coordinates 36.164, -119.431
←SSI-92 SSI Balloon Launches SSI-97→

SSI-93 (project designation CY-7) was the seventh launch of Project Cycloon on October 26, 2019. It was the zero pressure balloon equipped with altitude control (ballast mechanism), and launched alongside two other zero-pressure balloons at Onboarding. It was the first balloon in the folded topology as a result of a notably eventful filling, and consequently also experienced a noteable post-landing.

Project context


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

Avionics: TinyGPS, Teensy 3.2, BMP 280 transmitting at adjustable intervals over Rockblock. SPOT Trace. Ballast control; nichrome cutdown; GPS power reset MOSFET.

Power: 12 L91 lithium AA batteries. 3 L91 lithium AA batteries on resistive heater and cutdown.

Ballast: Legacy valbal mechanism with 300 g ballast.

Payload: Half valbal-style polycarbonate cylinder within styrofoam enclosure. Mass 1.25 kg including ballast.

Mass budget: 2.26 kg total.

Flight synopsis

Ascent rates against altitude
Flight profile

October 26 953 PDT: Balloon released after an attempted titration to 0.5 kg of free lift. Moderate winds made this difficult. However, within a few dozen seconds of release the balloon began to descend, and was caught barely within the southwestern boundaries of Brigantino park. A large leak at the top seal was discovered, motivating the decision to fold the envelope over. The balloon was re-filled and observed for 10 minutes for second release.

October 26 1014 PDT: Balloon released at approximate 1.5 m/s ascent with initial motion to the southwest.

Flight trajectory
Balloon Launches
2014-15 SSI-19202122
2015-16 SSI-23(a) • 2425262728293031323334353637383940414243
2016-17 444546474849505152
2018-19 8386879091
2019-20 929397