UBSEDS6 was our first launch using a 36” Qualatex Balloon. Despite a bumpy ascent over Bristol the balloon super-pressured and floated at about 8.6km. Favourable winds carried the balloon to Latvia before the tracker failed 14 hours into the flight.


The balloon was “pre-stretched” before flight but pumping air into the balloon using a slightly modified Omron M2 Blood Pressure Monitor. While in flight the balloon experiences about 2kPa of internal super-pressure at 8.5km float (this figure is a vague guess) the balloon was inflated to a pressure of 4.7kPa on the ground (measured as 35mmHg on the Omron M2).

Gif of the balloon inflating from 2.7kPa to 4.7KPa. This takes about 2 hours.

The difference between the balloon at the start and end of the process is very noticable. One of the slides below shows an un-modified balloon on the left and a pre-stretched envelope on the right.


During the day the balloon entered a very stable float at about 8.6km altitude and dropped to a similarly stable float at 8.2km during the night.


No major changes since last launch. The cause of tracker failure is unknown, but possibly due to cold (-30ºC).




  • Total distance traveled: 1746.9km
  • Great circle distance: 1721.1km
  • Maximum altitude: 8.7km
  • Countries passed through: gb nl de dk se lv



Thank you to all listeners who tracked this flight!

Callsign Telemetry Lines Received Longest Path
PE2G nl 603 373.9km
PE2BZ nl 573 346.2km
MH nl 518 359.0km
G8KNN gb 502 357.4km
F5APQ fr 492 395.4km
M0UPU gb 389 407.5km
G1DYQ gb 360 287.0km
G8DHE gb 338 240.8km
PE1ANS 336 401.0km
PB0AHX nl 327 382.1km
SM7DSE se 325 309.2km
M0ZBU gb 323 340.0km
0x17 gb 304 322.0km
ROS nl 274 330.5km
G0WXI gb 264 242.6km
PE1RQM nl 246 276.1km
NLincs gb 244 369.1km
G8FJG_2 gb 228 326.8km
PD5TON/A 221 282.1km
G8FJG_1 gb 210 288.4km
OZ1SKY dk 193 373.4km
SA6BSS se 174 1267.9km
G4AIU gb 166 257.4km
M0SBU gb 149 355.0km
GOS nl 122 234.2km
YL3CT lv 118 354.9km
G8ZBJ gb 106 163.4km
VA1DWR 98 4867.6km
g0nzo gb 98 283.2km
G8JNJ gb 91 253.7km
M0CJM gb 90 119.6km
SWL014 fr 80 370.2km
PD3T nl 68 348.7km
2E1FOV gb 66 292.1km
x-f 61
SP1TMN pl 56 372.6km
DUTCH nl 40 178.9km
Northants gb 28 114.3km
AlgidSpace gb 23 176.9km
YL2CP lv 22 268.6km
SP3MCY pl 20 1177.9km
PB5A nl 15 140.3km
G4YHE gb 11 186.8km
G7SVI gb 8 132.8km
G8IMN gb 4 136.9km
m6dnu 2