Thursday, 9 October 2014

The Summary

To summarize, I have to say that in the end everything worked as was supposed to, and the whole day went just fine. The payload collected temperature and trajectory data throughout the whole flight, and took some very interesting photos and videos on its way up and partially down. Here are some of the photos. The rest is in the Flickr gallery here: TT7 Flickr
 A view on Roznov pod Radhostem shortly after take off.
The balloon slowly rising above the low altitude mist.
A view on the mountain range above the town of Roznov. Here, restraining the northern low clouds from filling up the valley.
Still below the airplane travelling altitude.
Even the Moon peeked into the view.
One more view on Roznov and the mountain range down to the left. Some cumulus clouds forming in the middle and a massive front coming from the Southeast on the right.
The blackness of space is closer and closer.
Still rising higher...
...and higher.
The maximum altitude 34396m.
And the balloon bursts.
 Accelerating to as much as 36.52m/s.
A long way to go.
Pursuing Aegean Airlines' Airbus A321 on its way from Copenhagen to Athens.
And the farewell photo from the dying camera at about 15.5km.

I made a timelapse video from all of the photos from the payload. The images are too discontinuous to offer a decent spectacle, but it can give you an idea about the flight.

For an illustration, here is a video from around 34km in altitude. The remaining 15 videos are in the Flickr gallery.
These are images from the satellite to give an idea about the cloud cover from a different perspective. From the left to the right 11:00, 12:00, 13:00, 14:00 CEST (UTC+02:00).
Coincidentally, one of the predictions I made in the morning had the burst altitude set to 34434m. Almost spot on the actual maximum altitude. Unfortunately, I didn't prepare a projection with the descent speed as low as 2m/s, otherwise it might have shown the landing site almost exactly. The second picture is the actual trajectory. So to summarize, the expected ascent speed was 3.48m/s versus the actual average ascent speed of 4.21m/s. I think telling the intended helium volume when filling the balloon the way I did it, was not very accurate. Thus I overfilled the balloon a little. The expected burst altitude was 31434m versus the actual of 34396m. In this case, I was pleased and a little surprised that despite the greater amount of helium, the balloon had managed to surpass the level by that much. Almost 3 kilometers. On the other hand, the expected descent speed was way, way off. The difference between 5m/s and the actual value of 2m/s made the landing site 21km further to the west. The causation was definitely underestimating the parachute's capabilities.
This is the trajectory displayed in Google Earth. The launch in Roznov pod Radhostem, the burst 34396m above the village of Morkov and the landing in the village of Jindrichov. If anyone wants to examine it more closely, here is the KML file. TT7 kml And here are all the received telemetry sentences in a TXT file. TT7 txt All the data and data from many more HABs are downloadable from the Habitat website.
This is a diagram of the balloon's altitude and vertical speed. The balloon was launched from 420m and later achieved its maximum altitude of 34396m only to fall and land in 425m. The average ascent speed was 4.21m/s with the 6.19m/s maximum and the 2.95m/s minimum. The average descent speed was 5.45m/s with the 36.52m/s maximum and the 1.59m/s minimum. The whole flight took 4 hours and 2 minutes. The ascent lasted for 2 hours and 13 minutes while the descent took staggering 1 hour and 49 minutes as opposed to the expected 45 minutes. The launch time was 10:17, the burst 12:30 and the landing occured at 14:19 CEST.
This diagram shows the temperature measured by the datalogger. The flight started in 20°C and gradually dropped to the minimum of -45.7°C encountered at 11800m. Luckily, the gloomy predictions of the International Standard Atmosphere model promising -56.5°C didn't come true. Contrary, the balloon enjoyed pleasant 1.7°C at its maximum altitude.On its way back, the balloon went through two local minimums. The first at 21803m of -44.4°C followed by the second at 11204m of -41.2°C. After the landing, the balloon lay in a field on direct sunshine measuring a temperature of more than 30°C. Here is the MSS file from the datalogger. TT7 mss The file format requires a special Cometsystem's software for servicing the datalogger. For download here. Datalogger software The file also includes data from an internal probe, but since the datalogger was fairly isolated from the main part of the payload, I don't think it will be very informative about the actual temperature experienced by the electronic parts.
As I mentioned in the previous article, I wasn't the only one receiving the payload's transmission. In fact, I wasn't even the one who received the most sentences. Since I had to travel between different places during the flight, I was really glad that the payload's trajectory was thoroughly mapped by participants from Poland and Slovakia. Out of interest, I used the Habitat's statistics to find out who was the furthest telemetry recipient. It turned out to be somebody in Eastern Poland about 400km from the balloon. That is not bad for a cheap transmitter.
With all the diagrams and photos already posted, I am slowly getting to the last bits of information I am left with. And since both the flight and the blog are almost done, I should summarize how much it all cost. This is a list of all the things I bought (and remembered) during the preparations. The total cost of this project reached 9027 Czech Crowns which is currently about 329 Euros or 419 Dollars. I should mention that I have saved a great amount of money on helium. I was lucky enough to be allowed to use the leftovers of helium in a local company Retigo which uses it during manufacture. Otherwise, the helium in the quantity I needed could have easily added about 4000Kc or 170 Euros/185 Dollars to the total cost.
And that's about all to be said about my high altitude balloon project. In case you have any questions feel free to leave a comment or send me an email.

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