Figure 2. Shows the gondola being picked up for launch by Hercules.
We watch as the flight-train becomes stretched and a hard snap jerks one of our sensor boxes towards the sky. The sigh of relief and joy can be felt in the crowd but as we head back to the ground station the happiness turns into confusion. The bottom sensor box has stopped sending data 10 minutes before launch and we have lost all connection to it. The top sensor box follows the same fate at 10000 m. What could have caused this? When the experiments are retrieved in Finland the following day, a quick test shows that no more data has been saved to the memory cards. What could have caused this failure?
An extensive troubleshooting process is initiated. First of all, the cables are checked to find out if there were damaged but both the sensor boxes and the cables are undamaged. The batteries are checked afterwards, to find out if they were somehow prematurely drained. An analysis shows that the batteries are almost full. For our next test we pluged in the experiments and let them run as on the launch day and as we suspected, both of the boxes turn off automatically after a few hours. The problem seem to be in the software as the boxes think they have landed and therefore shut down. Currently, we do not really know how this can happen and further analysis needs to be done to pinpoint the issue.
Even though both boxes shut down earlier than expected during the flight, an objective analysis shows that the experiment is 50% successful as data was still collected during the ascent and at the border of the stratosphere.
Figure 1. Shows the launch vehicle, Hercules.
What happens with the data now that the EXIST experiment have flown?
This is when the Science division of EXIST will start doing post-processing of the data gathered from the launch. The post-processing of the data will be done in different steps. The first step is to distribute the raw data to EXISTs stakeholders. The second step is to start analyzing the data gathered. This will yield points of interest in the data and possible patterns that should be studied further. In this step data from ground station microphones will also be studied. The thirds step is to do further analysis of the things found in the second step. This is done by doing spectrum- and wave analysis of the data through numerical methods. By doing the analysis the Science division of EXIST wants to answer following bullet points.
* Is the experiment able to measure infrasound (sound with a frequency less than 20 Hz) in the Troposphere and Tropopause?
* Analyze noise affecting the microphone instrument.
* What caused events or patterns in the data?
Even though the data amount is a bit smaller than expected this process will take some time to finish to make sufficient statements regarding the data. The EXIST team will work on outreach during this process and will provide you readers with further updates in the future.
Thank you all for following and supporting our project.
At around noon, the 18th of October, the BEXUS 24 gondola successfully launched with all the experiments onboard, including EXISTs sensor boxes. Unfortunately, because of some unknown software error, both EXISTs sensor boxes turned off. One, a few minutes before launch, and the other one at an altitude of about 10000 m. But even with these unfortunate events the experiment deemed to be 50% successful.
At 3.30 in the middle of the night you could find personnel from each BEXUS team sitting patiently and a bit sleepy at their respective ground station, awaiting the preliminary launch at 7.30. The countdown timer can be seen everywhere on big screens, ticking down from 4 hours. The weather report was looking good so the launch was expected to take place without any mishaps. Out on the launchpad, SSC (Swedish space corporation) can be seen preparing the gondola and flight train for launch using the launch vehicle called Hercules.
Figure 4. Shows the tired EXIST team member Jonas Blidnert.
Figure 3. Shows the balloon on the launchpad. The balloon may look small now but it will expand to about 35 times the current size.
As the time passes by, more and more members of each team join the crews at the ground stations. At team EXIST, we can see on the computer screens the data being recorded and everything is working as expected. At around T-90 minutes, snow starts to gently fall. The countdown timer is suddenly halted as the snow builds up on the ground and on the launch equipment. The gondola and equipment is brought indoors and a status-check is made. The snow has caused dangerous humidity and wetness, both on and inside our sensor boxes, but nothing appears to be damaged.
A few hours later, when the snowing has stopped, the countdown resets. Once again the gondola along with all the experiments are driven out to the launchpad. New system tests; everything checks out. The balloon, which can hold 12000 m^3, is being rolled out at T-45 minutes and starts being inflated at T-15 minutes. Now, every team is standing in excitement at the edge of the launchfield viewing the last preparations before liftoff. The sun is shining in the distance and the weather is perfect for a launch. The countdown can now be heard in the loudspeaker; “3, 2, 1” and then it goes.