[GCARC] Balloon update for tomorrow

[Jon Pearce]

Once again we're going to make an attempt to launch a balloon tomorrow morning, probably between about 11:00 AM and noon. Here's a quick summary of launches to date:

Flight 1: A Mylar party balloon that was unintentionally overinflated and vented at the bottom to allow gas to escape, carrying a Traquito transmitter and powered by a LiPo battery. Our goal for this flight was to understand the telemetry and launch process, and we expected this balloon to burst before reaching altitude. Result: The balloon rose to about 21,000 feet and then slowly descended, landing in the Atlantic Ocean slightly into international waters.

Flight 2: Similar to Flight 1 except that the balloon was carefully filled to give 7 grams of lift and sealed at the bottom. As before we didn't expect this balloon to survive but again wanted to test the telemetry tracking and launch process and find out what would cause the initial failure. Result: The balloon reached an altitude of about 29,000 feet before the LiPo battery froze and telemetry ceased. Several hours later telemetry resumed and showed the balloon on the ground in eastern Delaware.

Flight 3: An ORBS mylar balloon of a type that has been shown to successfully reach equilibrium in the upper atmosphere and circumnavigate the earth, carrying a Traquito transmitter and two 5 volt solar cells. It was carefully filled with helium to create 5 grams of lift. Result: The balloon cleared the trees on ascent, validating that 5 grams of lift is enough to get it rising. We never received telemetry from the transmitter, however, probably due to the misplacement of the solar cells.

Tomorrow's flight will be an ORBS balloon filled to create 5 grams of lift carrying a ZachTech tracker on which are mounted two 5V cells connected in parallel. The ZachTech also has diodes to prevent one solar cell's current from flowing into the other cell when unevenly lighted and also has two 1 farad supercapacitors to maintain voltage for a short period when the sun dims.

The goal for this flight will be to reach equilibrium at altitude (probably around 40,000 feet) and follow the wind currents for a long period, hopefully measured in weeks or months. Since the telemetry is powered by solar cells, and not by batteries as on the previous flights, we may not get telemetry data until the balloon has reached an altitude above any clouds and the sun angle on the cells is high enough to illuminate them brightly. Currently the prevailing winds at altitude are flowing toward the northeast so we'd expect the balloon to follow a path up the Atlantic coast north of Nova Scotia and then turn northeast, sweeping to the southeast and then ending up over England or France and hopefully continuing from there.

Once we've received telemetry we'll publish the links so that others can track. Hopefully this will be an interesting event for club members.

73 de Jon WB2MNF with Doug KD2VQA and Mike KG4JYA