Day 1: 20-Feb-2017
Day 2: 21-Feb-2017
Live tracking
Photos of the launch
Transmitter photos

Like the former flights, this one also uses a special U3S firmware version.

S-21 was launched successfully on 20-Feb-2017 at about 12:20 UT in Toronto, Canada. No transmissions were heard from S21 after day 2. So presumably the balloon went down somewhere in the Atlantic overnight. RIP. 

Live tracking

Day 2, 21-Feb-2017

S21 woke up over Puerto Rico. But unfortunately the GPS stopped providing further position updates, so the rest of the day the path is unknown - though S21 continued transmitting just fine.

Day 1, 20-Feb-2017

Dave had a successful launch (see photos below) but it took a couple of hours for the transmitter to properly start up - so the first part of the ascent and path was not recorded. S21 picked up huge speed and headed South-East. The NOAA prediction suggests it should head for Puerto Rico (see below).

Photos of the launch

A fine launch, it took some time though for the transmitter to start correct transmissions. By then S21 was already across the Canada/US border and picking up speed.

Transmitter photos

Dave's list of changes:

Giving another go with the Sim28m gps module to see about 10km blindness
Mod for extending balloon mode by limiting gps power on to > 3.1v which should defeat the lipo protection circuit motoring which I suspect was resetting the Sim28m
new pcb
25ppm osc 27mhz
no 2.54 pins through the foam only 32 ga magnet wire.
slimmer radio container but larger pcb
Thinner wire for hangar
7 solar cells with voltage limit LDO of 4.0v to stop lipo battery plating.
It should fly with tripole antenna for about 11.25gms or so.... lightest yet.

Actual total weight according to the measurements shown in the photo below is 10.26 grams.