Sunday, May 12, 2013

Launch Campaign - Day 10, Launch of REXUS 13!

Seeing the Launch getting cancelled with shifting blue skies did not make us very confident when we woke up early in the morning and realized it was snowing. But the winds were calm the only problem was the bad sight that could affect the recovery of the rocket. The major part of the team came to the radar hill a few minutes before 5.30 am (the rest had to stay at the ground station).

Not too convincing weather
At 5.30 there was a planned hold for 15 min in the countdown to await the launch window and examine the weather conditions.

Fortunately we could see the haze decreased and the weather got clearer simultaneously as the winds remained calm – we began to hope. At 5.45 the announced that the countdown could be resumed and now we know that only critical weather changes could stop the countdown.

The upcoming 15 minutes were very exciting and nervous:

T - 10m Experiment power is switched on.
T - 8m SOLAR is armed and ready for launch
T - 2m We confirm our readiness for flight
T - 0 Lift off!

So the launch did happen and can be seen here:


At this moment the Esrange crew had done their job and the quality of our still had to be proven:

T + 90s Soldering starts
T + 600s End of flight.

So far so good, the soldering had been performed. But how about the pressure in our chambers? To call the flight successful we had to get vacuum in the vacuum chamber and not lose too much pressure in our pressurized chamber. Regarding the pressurized chamber we hoped for a pressure drop less than 20% ideally below 10%. The results were visualized directly in our ground station:

SOLAR Ground Station - revealing the first flight results
As seen in the pressure graphs the experiment performed really well. The pressure dropped immediately in the vacuum chamber and in the pressurized chamber the pressure did not drop but INCREASED (due to the increased temperature during the soldering).

The (so far) very successful flight was celebrated with a champagne breakfast while the recovery mission started. We still had one concern; had all samples been melted?

After roughly 2.5 hours the helicopter landed on Esrange again carrying the rockets payload.


Due to a main parachute failure and a landing in 35 m/s the nosecone of the rocket was a bit demolished as seen in the picture, but fortunately all experiments had survived the flight.

The REXUS 13 payload immediately after the recovery
"I think you belong to Gryffindor Team SOLAR"


The rocket was disassembled and we could soon start our own disassembly. We opened the chambers one by one and found the following results beneath the hats:

Results for pressurized chamber - looking good!
Results for vacuum chamber - looking good!
As you can see all samples melted as planned and a successful flight was a fact. You can also see how the samples looks like before and after flight here


During the evening we had dinner and a hilarious launch party, which can be summarized with one picture:


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