Technical info

Model: Vaisala RS92-SGPA

Manufactured in 2013-11-25. Launched 10 years after manufacturing!

XDATA sensor onboard was Radioactivity Sensor, Vaisala NSS921.

Flight

This sonde was launched from Jokioinen, Finland on 12th of December 2023.

Flight path available at Sondehub.org.

Search and rescue

The last position was received pretty low - 226m from sea level. However due to inaccuracy of RS92 GPS my pre-calculated landing location didn't provide any results. Just snow, snow all around on the field and no sonde parts visible. I tried to get radio transmission with rdzsonde, but nothing. The light was going out as it is almost the darkest time here in Finland and I knew I didn't have too much time left. I decided to walk the landing path further until I saw something far away - could that be the balloon?

And yes it was. Balloon found. I started to reel in the line but ended up with nothing - the line had broken. Tested rdzsonde and now I got few packets but no GPS location as probably the RS92 didn't get GPS fix on the ground.

Good thing is that I knew I was close to the sonde and it was alive - so it was somewhere. Didn't took that much time until I spotted suspicious hole in the snowy field. The shape of it didn't match my expectations but when I got closer I remembered that RS92 is shaped more like a square. I couldn't see the sonde without digging and after I started digging the snow, I found the sonde blinking its green light!

In total I spent 3 hours by car but the trip was well worth it. Beautiful sceneries everywhere as all trees are covered in snow. Temperature was -10 degrees celcius and calm wind.

Radioactivity sensor

Detectors Two Geiger-Müller tubes, low-temperature versions:
Philips ZP 1208 for y-radiation and
Philips ZP 1328 for y radiation and high energy (>0.25 MeV) ß-radiation

Measurement range
y-channel y and ß-channels
- Counts per second 0 - 870 0 - 870
- can rate mR/h* 0.1 - 60 0.4 - 120
- Activity kBq/m3* 2 - 1000 6 - 2000

Special balloon

• Very rare to see such combo flying at least here in Finland
• RS92 is not used anymore in every day use, so we see less and less flights of good old '92
• Included radioactivity sensor. Must be expensive :)
• Launched 10 years after manufacturing.

More to come..

More photos, teardown etc. coming up