La Rose de l’Espace : all you want to know !

Written by Helena Furgoni

25th July 2019

Keeping our promise…

Here are the results collected from the balloon from “La Rose de l’Espace“, launched into the stratosphere last month. We were amazed by some of the results, which might surprise you too! While ascending to an altitude of 35 kilometres (114 000 feet), the polystyrene nacelle was exposed to extreme conditions. The height curve is more symmetrical it is ought to be, this is due to the fact that the balloon, instead of exploding in the air and descending with a parachute, ripped and fell more slowly than expected.

A large covered area

The altitude, combined with the distance covered, allowed us a good network coverage. The balloon followed the wind currents, without moving too far away, which helped the team to recover the nacelle very quickly (and it was a major factor for the success of the mission). The balloon covered a total cumulative distance of 174km.

Our several antennas in Strasbourg and the region have all detected the sounding balloon. Great news for Strataggem! (even if we had no doubt on the subject).

Extreme conditions

The balloon was subjected to extreme conditions throughout the entire journey, including constant dropping temperature and pressure, or speed when the nacelle was exposed to fairly strong winds. As a result, the batteries in our equipment, already tired from the long preparation and flight time (longer than expected), were finished by the very low temperature, which resulted in higher energy consumption. Some of the sensors shut down  during the descent, from 14:45 ( after 4:10 hours of operation). The balloon was then at an altitude of 18,285 metres, and the outside temperature reached -30°C.

The temperature captured inside the box was milder: while the outside climate reached -46°C at an altitude of 13,000 m, the coldest temperature recorded inside the nacelle did not drop below -9°C.

As a comparison, in the village of Oymyakon in Siberia, considered to be the coldest village in the world, the average temperature in January is -50°C. An extremely hostile temperature when you know that a negative cold room (below 0°C) cannot go below -30°C.

We were particularly amazed by the speed: the nacelle, a few tens of centimeters in diameter, was subjected to speed peaks of up to 108 km/h at an altitude of 31,000 m, but without being damaged.

Barometric pressure dropped to 7.4 hectopascals. At sea level, the pressure is commonly 1013 hectopascals, and on average, the atmospheric pressure decreases by 1 hPa every 8 meters. The balloon, as it climbs up, has significantly approached the absolute void.

Thanks again to the “Rose de l’Espace team”, without whom this experience would not have been possible. And, we hope, see you next year!

 

 

 

The key numbers

35 km   the maximum altitude reached by the balloon

174 km   the total distance covered

46°C   the lowest temperature captured outside the box

108km/h   the maximum speed reached

7,4 hPa   the lowest barometric pressure recorded by the balloon