On 23rd May we launched our first high altitude balloon (HAB) from Lurgan. Following a very hectic few days and many late nights the weather and drift predictions were good and we were go for launch and headed to Lurgan Park.
After the payload was tested and packed final radio tests took place and some training on how to use the radio equipment. We had three chase cars in place – two to leave immediately and one to remain behind to feed telemetry until the launch was high enough for local radio amateurs to track.
After a few false starts and back-and-forth we began inflation.
Inflation went fairly well though there was some leaks where we were fitting different diameter pipes together. Given the relatively low pressures though it could be largely removed by gripping the junction as hard as possible. The most difficult bit was trying to hang the payload and extra weight (once removed = lift) off the bottom and judge it well. But the balloon soon filled up! Once we had inflated to the correct (we hoped!) amount it was time for release.
The balloon climbed away nicely and we were immediately getting good data back over both radio links. Chase cars away and the base car remained on station uploading data as received. Fairly shortly other radio receivers started reception as well and pictures began to upload to habhub.
After initially tracking north almost up to Lough Neagh as it climbed the drift swung South-West again. Images sent back included this of Lough Neagh.
Everything was fine until 16km at which point radio data was lost on both channels. We were still seeing a transmission on the frequency but this was a single peaked carrier wave only. The assumption is that the Pi (running both transmissions) crashed but the transmitters remained powered, hence the signal but no data.
Undeterred the chase cars headed onwards trying to track the signal. An hour and a half after data had stopped transmitting the signal was lost entirely. All three cars worked around the area but failed to pick up a definite signal though some possibilities of a signal were found, but not strong enough to be confirmed. As of this time Balloon 1 is lost somewhere in a couple of hundred square miles around an axis from Enniskillen to Fivemiletown and Carrickroe. The hope is that someone will find the payload with the contact cards and get in touch.
Flight History
- 1511 Liftoff
- 1519 At 2km being widely tracked
- 1615 At 16km loss of data
- 1714 Burst (we have this from radio amateurs who, listening to the waveform, can detect when the burst causes the transmitted to tumble) – the estimated altitude was 30.1km
- 1747 Loss of signal from Phil’s fixed radio receiver (below horizon)
- 1749 Loss of signal from Andrew’s mobile radio receiver (below horizon)
- 1750-1754 Touchdown
This would give a ascent time of 2h2m to ~30km which was similar to predictions given gas volume and a descent time of ~50 minutes.
Lessons Learnt
- Pis can crash and a single point of failure for tracking is a bad idea where it can be avoided whatever the tracking system
- Ballooning is cool and we get good feeds and data
- The setup took far longer than expected (was our first time) – but we could streamline by pre-packing radio sets for cars etc
- The filling was a bit chaotic and Heath-Robinson to say the least – needs to be thought through more clearly
- Gas was lost during the filling – junctions need to be remade to be gas tight