First flight
EUSO: The amphibious astrophysics gondola…
Preparations for the flight of the EUSO-Balloon gondola began in the late afternoon of Sunday 24 August.
The EUSO-Balloon gondola arrives at the launch base © CNES
The main balloon envelope arrives © CNES
The launch director adjusted the countdown to delay inflation of the auxiliary balloons for as long as possible and wait for ground winds to abate..
The launch was thus able to go ahead between 20:30 and 21:00, an important scientific requirement for this mission.
Subsequent pre-launch operations were nominal. The auxiliary balloons were inflated to lift the EUSO payload gondola during inflation of the main balloon, which required two helium gas trailers, then the launch director gave the ‘go’ to release the 400,000-m3 balloon when ground wind conditions were right at 20:54.
The launch team unfurls and opens the main balloon’s protective sheath © CNES
Inflation of the main balloon is complete © CNES
You may wonder why launch team members are only using one arm or one leg during operations to test the release valve on the ground and adjust it during balloon inflation. Could they be trying out a new procedure or maybe it’s a bizarre kind of initiation ceremony?
Valve operations involve a lot of balancing © CNES
Balloon lift-off © CNES
Flight phases
After reaching its float altitude, the balloon drifted with the winds aloft, collecting science data and notably flying over densely populated areas.
Intensity map of the UV background in photons m-2sr-1ns-1 with a logarithmic scale. Bright zones with high intensity are from artificial light in Timmins and the surrounding area, mines and airport. Red and blue zones indicate cloud cover.
The telecommand to terminate the flight was sent at 4:20 on Monday 25 August once the mission had flown through the astronomical night as required by the science lead. The exact separation time was decided to try to land the balloon in as dry an area as possible.
However, wind strength and direction in the different layers of the atmosphere mean the exact location where the flight train will land cannot be estimated precisely.
EUSO-Balloon floats… as expected!
The gondola floating in a lake after splashing down © CNES
In fact, the flight train’s estimated dry landing site turned out in reality to be a 200-metre-wide lake…
And as the lake was 50 km from the nearest village, the recovery teams had their work cut out!
But they found the EUSO-Balloon gondola floating as designed on the lake’s surface and perfectly dry inside.
The two auxiliary gondolas were also floating but not designed to be waterproof.
On the other hand, the balloon envelope was recovered on dry land!
Flight results
Flight results 
(pptx - 4.13 Mo)
Next flight
... 2017 ...
