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--- projects:picoatlas:picoatlasi [2011/01/19 07:28] – [Monday - Launch] jcoxon
+++ projects:picoatlas:picoatlasi [2011/01/19 07:59] (current) – [Improvements for MkII] jcoxon
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   - Get bubblewrap
 ===== Monday - Launch =====
-  * Launch itself was easy
+==== Mission report ====
+After arriving a little late we met in CUED, collected the launch gear and headed over to Churchill where we met up with G8KHW. After adding some more insulation to the payload we turned it on and placed it outside in the rain where it got a lock in a few minutes. We then set about filling the balloons. Using a piece of silicone tubing left over from ballasthalo we pushed this up into the foil balloon through the internal valve and attached this with tape to the normal filling tube. We inflated the first balloon ~50% and realised that we wouldn't get enough lift. We then filled the second large balloon and still not enough lift so we also attached the two spare small 48cm balloons we had spare. After removing the newly added insulation and the antenna radial supporting straws we had a bit of positive launch and released the balloon.
+The ascent rate was incredibly slow, reaching cloud layers resulted in the balloon nearly stopping ascending and occasionally descending. After an hour in the air and a good number of stations receiving the data the launch team dispersed. The balloon continued to climb slowly with an slow reduction in ascent rate. As can be seen on the altitude graph it seems to have dropped a bit, climbed again and then started to ascend. Its difficult to work out exactly what happened and will certainly require another flight which is slightly more scientific in its calculations.
+The balloon gently descended over Ipswich then turn south crossing over a number of estuaries to land in Essex to the west of Harwich. The recovery team went out that night and while were able to pick up the last position of the payload over the radio couldn't see the payload and due to the rain it was incredibly muddy. The next day as they headed over to try again there was a phone call to say the farmer had recovered it for us and placed it in his garage for us to collect.
+On arriving we found the balloons and payload sitting on the ceiling of the garage - obviously the morning sun had warmed the He sufficiently for enough lift. The payload was still transmitting though was showing signs of the battery running out as the tx was unstable, it was also quite wet - the foam insulation soaking up water.
+  * Launch points
     * Created a 'spacer' to allow easy filling - just a piece of tape over the end of our normal filling tube with a bit of 3mm tubing pushed through and then more tape to seal.
     * Very early on we found that 1 balloon wasn't enough, 2 balloons wasn't enough, 2 balloons + 2 small balloons was enough when we removed all the external insulation on the payload and the straw supports on the antenna. In future we'll need at least 3 balloons and a lighter payload.
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     * Its a challenge to fill multiple balloons equally.
     * If use use a rubber tube to fill when you remove it you will end up pulling out the internal seal plastic - means you can't fill it up more however does mean you can seal the balloon well (twist and tape would work well).
-  * Balloon didn't float - though the ascent rate slowed considerable, looking at the altitude graph you can see a number of blips which were probably cloud layers. I think temperature had a lot of effect on the ascent rate and with the sun setting + losing on of the small balloons resulted in the slow descent.
+  * Balloon didn't float - though the ascent rate slowed considerable, looking at the altitude graph you can see a number of blips which were probably cloud layers.
+    * Temperature seems to have had a lot of effect on the ascent rate and with the sun beginning to set
+    * The lose of one of the 'lift' small balloons
+    * Foam insulation soaking up water
   * Tracking went well - got good reception reports though out the flight despite the low altitude.
-  * Attempted recovery that night, while the last position was found it was too dark/muddy to recover then, the farmer found it in the morning and called the contact number. He had put it in his barn and when I got there to collect it it was on the ceiling - even missing a small balloon it had enough lift that morning - if it hadn't got tangled in the fence then it could have taken off again.
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   * Temperature sensor
   * Photodiode sensor
+  * Don't use foam insulation as it'll soak up water and increased the payload weight
+  * Code mistake
+    * Due to a mistake with using > rather than >= it dropped into night mode between 1600 and 1700 rather than evening mode