In this post is a graph of internal and external temperature (all in Kelvin) against time. The graph we see is very much expected and we are fortunate it was like this as the batteries would not have worked terribly well if it dropped too much.
Internal and External Temp vs Time.
The external temperature reading themselves aren’t what I’d expect. Temperatures go down below zero in some parts of the atmosphere. I put this down to the fact the temperature sensor is mostly enclosed in some Areldite (glue) to reduce chance of shorting of leads in ‘wet’ environment. We are also going very quickly through the various zones of the atmosphere which means we might not have enough time for the temperature to settle.
What is interesting is the lag between internal temperature and external temperature. The Internal temperature was recorded inside a Polycarbonate box, which inside was generating some heat itself – majority from the RFD900 radio and other electrical components.
Overall, the flight went exceedingly well. Over the course of the next few weeks, we will go through some of results/measurements.
We sum up in this Post what went well and what didn’t go so well.
Quick Analysis
The radio communications link went well between the groundstation and the payload. At no time did we lose communications, except when the payload descended below the hill to its landing spot. The temperature of the payload box also remained at a healthy temperature and the radio modem temperature in the payload did not get very hot as was expected! Which was surprising.
The photo stills taken by the Linksprite lived up to our expectations. We got about 20 photos. While the colour in them doesn’t seem as “rich” as one would expect, I’m still very happy with the. We were able to download two of them with no issues during the flight.
The temperature sensors didn’t drop down to the cold temperature I was expecting. Perhaps this is because the temperature sensor was partially encased in Areldite glue to stop short-circuiting if there was any moisture. Not too sure.
The tracking software worked, but there were TOO many GPS data points and the text at each data point overlapped other points. This I think slowed down the Beaglebone Black which made it almost impossible to ‘zoom’ in and view the way points of the flight. Some method of thinning them out is required…and a different method/approach of showing GPS information at each way point. Perhaps something like the Spot Messenger public facing page.
The GPS worked well, right up to 28.1km! This is fantastic. The original GPS module we had in the payload was one that could only work up to 18km. So it was great that this new GPS (which is supposed to work up to 50km) did work so well.
The “approximate” altitude calculation (based on air pressure) seemed to be way off! It is possible that this was outputting in feet (not metres) and hence the inflated approximate altitude values.
The Video camera using the HackHD was very disappointing. I _had_ noticed some issue with very over-exposure (too bright/white) during some testing, but failed to resolve this. As a result, most of the flight video was extremely white. It appears HackHD does not have an AutoWhite balance control.
The deployment/launch of the balloon was a stunning success. Everyone knew what they had to do and there were no problems with the cylinder.
Because the balloon was recovered a week after the launch and the onboard siren battery only lasts 27hrs, we could not depend upon this to assist with recovery. We are thinking of having one that is on for 30 seconds then off for 5 minutes, then on again..etc. This could extend the battery life significantly and make recovery a LOT easier.
The last code update to allow the ground controller to disable/enable picture download was a fantastic feature that helped significantly. We would have had a lot less photos taken (because the payload would have spent more time sending photos and not taking them). This control also enabled us to focus on the tracking as opposed to the photos side, which is not as important.
From these observations, we will determine what improvements can be made for future flights (should we conduct future missions).
We successfully recovered the payload on Saturday the 8th of November. It was a very big exercise that required a lot of careful thought and planning. This Post goes over some of the details of this.
The Landing
The payload had landed about 7km from the Burke Development road, about 13km west of Petford. The exact latitude/longitude being -17.3085/144.82935. It landed in some of the most inhospitable land around. If it had landed south of the Burke Development road, we could have quite easily accessed it. For the 7 days prior to recovery, the Spot Messenger continued to spit out more data points around this latitude/longitude. Because the Spot Messenger is movement-activated, this indicated to me that it must be up in a tree swinging about whenever a breeze came along.
Immediately after the launch, the launch team (Csaba, Emilien and myself) committed ourselves to coming back and picking it up.
The Equipment
We made up a list of what we needed pick up the payload, to ensure we could do it safely.
Item
Quantity
Notes
Water
5 Litres PER PERSON
5 litters with supplements for electoyte loss ( sport drinks or fruit / whole meal bread ) I think 10L will wiegh too much. AGreed. Make sure we have a good 1 litre drink before setting off
Electrolytes
(Enough for 10 litres)
Nut Bars
10 EACH
Tuna Cans
3 EACH
Copy of map/routes
1 EACH
Suncream
1 Stick
Repellant
1 Stick
Umbrella
1 EACH
Do we really need this? No. Let’s not get it. It will be a burden.
Blade/knife
1 EACH
rope
Pink Flagging Tape
1000 metres
Get from Bunnings.
Walkie Talkies
2
From AusTek on Friday
Satellite Phone
1
From AusTek on Friday
EPirb
1
PLB from epirbhire.com.au
Compass
1
I have one
Spare Compass
1
Mobile Phones
1 EACH
AAA Batteries
6
For SPot Messenger…when we find it…if we NEED to use it!
Pens
3
Paper
10 sheets
Mirror
2
to signal for help?
Matches
2 packs
First Aid Kit
1
Back Pack
2
I will get myself one from BCF. Csaba, do you have one?
7.5 Litre water
1
20Litre spare water
1
Laptop
1
Fruit
Bananas and Apples
Clothing
Notes
Long Light Pants
Boots
Long arm T-Shirt
Long arm T-shirt could be a little hot
Jumper
IN case of overnight issues
Full Brim Hat
We also brought an Axe.
The Plan
Initially it looked like we would need to walk the 7km from the road and back to recover the payload. Upon closer inspection, it became obvious that there was a barely used track that we could drive out and get within approximately 3km of the landing site. Terrific!
We are pretty sure now that if we had attempted the 14km round-trip walk, we would have failed.
I went about investigating the exact path using google maps. I took screenshots of the the path to drive and walk and put GPS Latitude/Longitude points at various places. I also put in some info indicating approximate distances. An example of one of these is below:-
One of the ‘maps’ of our trek
I printed four copies of these, giving one to Loretta, one to Anna, and two for ourselves. We laminated one of our copies ‘just in case’.
The Timing
We finally decided on the following
– Pick up Csaba at 4:45
– Pick up Emilien at 5:05
– Drive to track (13km east of Petford) at 7:15
– Drive out to walking point – arriving approx 7:45
– Prepare for walk (7:45 to 8)
– Walk out to site (8 to 8:45)
– Collect payload (8:45 to 9:30)
– Walk back 9:30 to 10:15
– Drive back to Road (10:15 to 11:00)
– Drive back to Cairns 11:00 to 13:00
These times went out the door though. We finally got to our start-walking point at about 9:20 and commenced our walk about 9:30. We didn’t get out to the balloon landing site until about 12:15 and we found the balloon about 15min later and then didn’t get back to the car until about 2:30pm. Then we drove back to the road…getting there around 15:30 and finally got back to Cairns about 18:00.
It was an absolutely exhausting day. After the pickup and before going home we dropped by Dimbulah petrol station and had a good feed and drink!
The days proceedings
We drove very carefully from the sealed road out to the start-walking point. Every 20 metres or so, Emilien would get out of the car and put a pink ribbon on the trees/shrubs. We occasionally looked back to ensure we could see the pink ribbons we had left on trees.
Eventually we got to within ~3km (The way the crows flies) of the landing point. We were actually able to drive a little further than we thought we could based on the Google maps, but this didn’t translate to a reduced walk.
Csaba and myself did the hike, while Emilien stayed with the 4WD. We periodically contacted Emilien on the Walkie-Talkies giving him an update on our progress. We kept the PLB and the Satellite phone with us and made some Satellite phone calls to Anna and Loretta, giving them updates on our progress and to belay any fears they may have of our “adventure”.
It was hot and very tiring. I used up all the water (bar 600ml) in my backpack. (I had taken roughly 4.8 litres of water). I had taken several oranges and consumed two on my walk. They provide almost instant relief and renewed energy.
Along our trek, we saw a wild boar that fortunately ran away from us, several Kangaroos, including a really small one the side of a cat, plenty of cows and horses. We did not see any snakes, but we did see a lot of butterflies!
Eventually we found the payload after I reminded Csaba that it was back a little and up the hill and more then likely in a tree! Within 2 minutes, Csaba had found it! Up a 10metre tree! I tried climbing the tree but only scratched myself and tore my pants. The saw was futile. So we ended up using some rope and a rock to “pull” it down…basically rip it off from the parachute. (Parachute and part of burst balloon left in the tree). We then picked it up and walked back to the car. It was easy/fast on the way back because we just followed the pink ribbons that I had put on each tree every 10 metres on the walk to the landing.
Below are some pictures:-
The drive, 4wD and trek (the ‘Z’ portion was the walk) – From spot Messenger
Emilien holding payload
Joe holding the payload on walk back
Csaba holding the Sat Phone and folder on walk back
Unfortunately, we haven’t been able to recover it because it is so far off the “beaten” track. However, it has been a stunning success. We were able to track it the entire launch, except when it dropped below 1115 metres (behind a hill). Our Spot Messenger worked well. It has given us the final landing spot.
We managed to collect a lot of data and downloaded two pictures. See these pictures below:-
First one is at approx 5000m, the second is at approx 23,000m. Notice the moon in the second photo?
We aim to hike out to the landing spot next weekend and recover the payload.
