Felix became really keen in getting an ozone probe. So we gave it another go. The prediction pointed to near Kempten. We saddled up and drove there. En route, we would check the position of the probe. It was last seen at 9:07 near Kröbelbauer. We arrived around 60 minutes later. No signal. We did not give up. As went down very quickly with 13 m/s it was pretty clear where the probe must have landed. It was equally clear that somebody had retrieved it. The next 3 hours we wandered around looking with and without binoculars for the probe, before we went back.

On the way back, we received the signal of the Stuttgart probe. Near Köngen, our path and that of the probe crossed. As we were close, we detoured and went to the landing zone hoping for a bycatch.

[13494] (P0430252) Mo 2018-08-20 14:04:12.000 lat: 48.69841 lon: 9.39782 alt: 398.61 vH: 0.0 D: 135.7° vV: 0.1

Here, the signal was really strong even without antenna. There was however no trace of the probe itself. The trees were high and we were tiered. After a short search, we decided to go home.

Update on 2018-09-03

As I learn from Rapid Rolf, he had located the ozone probe pretty close to the predicted landing point shortly after landing. The probe had landed in a fenced-off meadow in that cows had been put inside. Felix and I had considered the possibility that the probe had fallen into the meadow and was crushed by a cow. We had scanned the meadow thoroughly  with the binoculars to no avail.

Update on 2018-11-01

I went to look for the RS41 probe at the received GPS coordinates near Deizisau. I did not find a trace of the probe however.

Update on 2018-11-10

With the wind blowing strongly from the East, the probes launched at Stuttgart flew far away for weeks.  And so I paid P0430252 another visit in a forest near Deizisau. Knowing that the wind took the probe southward on the day it landed and also knowing that the probe itself touches the ground first, I searched for the parachute south of the measured landing position. I eventually found it in a tree. Unfortunately, the thread fixing the probe and the parachute has ripped apart and is nowhere to be seen. So no lead to the probe itself — but a proof that the probe was or still is somewhere in the vicinity 🙂 GPS reception in the forest below the foliage is  somewhat inaccurate. So even though I have a fix of the probe and the probe is normally not more than 5m away from it, I am not able to determine my own position with high accuracy. In addition, there are still many leaves on the trees, so it is also difficult to make out a small white box up in the trees visually. In another 2-4 weeks, the situation will have improved…

Update on 2018-11-24

As I was driving in the direction of Deizisau anyways, I gave it another go. Many more leaves had fallen down,  and the tree tops were better visible. I scanned the tree tops to no avail however.

Update on 2018-11-25

On the way back from the airport, I stopped by once more to look for the probe at Deizisau. I tried to pinpoint the telemetry position with the Iphone’s GPS and scanned the nearby tree tops with the binoculars both to no avail. The probe was certainly still around somewhere. Time for a more systematic approach. So what did I know about the probe?

1) During most time of its flight, the probe flew predominantly in easterly direction. During the final part of the descent, the probe however changed its course to the south and flew mostly around 140°-160°.  Nearing the ground, the probe flew close to 180° sometimes circling.

2) I had found the parachute. The GPS position of the parachute was hard to determine. I tried to use the Iphone’s GPS to pinpoint it. The blue line in the picture below was actually taken when I was standing motionless under the parachute. So I estimated the position by trying to find distinctive spots in the texture of the forest depicted by google maps and matching that to my surroundins. A line going from the probe to the deduced position of parachute will follow a course of about 160°. That is in line with the telemetry data of the probe.

3) The received position of the probe is normally off by 5 meters max. Again, with the Iphone’s GPS not working too accurate in the forest that information does not help much. Using some overturned trees as landmark, I was able to get a much better feeling on where  to place the measured landing  position of the probe. Since I had thoroughly checked the tree tops to the east of the received landing position, I decided to look for the probe on the western side of the measured  position.  I assumed it to be within a sector that has an opening angle of 20° as  seen from the parachute’s position.

4) The thread mating the probe to the parachute is around 55 meters long. As the threads does not go directly from parachute to probe but follows the general envelope of the forest (e.g. tree tops that stick out) or sags, I estimated the actual distance to be around 35- 45 meters. The line connecting telemetry position of the probe with the parachute has a length of 45 meters.

5) Using the compass function of the Iphone and counting the steps when walking away from the tree with the parachute, I started to look for the probe at a distance of around 40 meters and scanned the treetops for the probe and the rests of the tether in the 20° sector.  I pretty quickly found first the tether and then the probe hanging high in a tree top. When Felix and myself came for the first time, I had actually suspected that the probe had landed on that very tree. The foliage however had obstructed the view until now, so I had not seen it during my previous attempts to locate it.

Looking at google maps, the probe is far more than 5 meters away from the last received position which is rather unusual. A storm rattling on the tree branches might have very well moved the tethered probe to its current where-about.

So what now? The probe is too high to recovery it. The thread seems to be under tension rubbing on tree branches every time they move in the wind. Eventually the thread will fail and the probe will plunge down. I might come by to check whenever I will be in the area.

Update 2018-12-02

The probe hangs still where I found it during my last visit. I guess it will require some storms to bring it down.

Update 2019-03-24

Even after the severe storms of the last weeks, the probe still hangs on the tree .

Update 2020-01-26

The probe still hangs where it was.

Update on 2021-02-07

The probe has changed color and is now sprinkled with with black dots. But it steadily hangs where it came to rest 2,5 years ago.

Update on 2021-04-11

Annoyed being confined to the vicinity of our house by corvid-19, I decided to go for a walk. Lacking good ideas for destinations, I went to look for the probe.

Arriving at the tree, I trained the binoculars to the probe … and saw nothing but branches. The probe had vanished. This could only mean one thing — the thread finally had given in and the probe had made its way down. I looked around and almost immediately spotted a white object. Nearing it, I saw that it was indeed the probe. The sticker had turned from yellow to white, and there were traces of  moss. Some bits of the styrofoam are chipped away either by animals or by the plunge on its way down.  The sensor beam became rusty and the wire forming the temperature sensor is cut.

Back home, I dismantled the probe, and swapped the batteries. Due to the broken temperature sensor, the self check fails. The probe however still sends. In the inside, I spotted a web and an a small caterpillar in something that could be a cocoon. And I found something that resembles an eggshell. After checking in the internet, I suspected it to be the caterpillar of a Yponomeuta. When going to bed later on, I discovered a butterfly or moth with white wings which would support this hypothesis. When I tried to investigate further the next morning, the cocoon was empty.