An international team of physicists and balloonists flew a helium-filled aerial vessel between Sweden and Canada to study the atmosphere from this high perch.
Eight hundred thousand cubic metres of helium and a light canvas 15 microns thick, a giant balloon suspends an unmanned gondola filled with 900 kilograms of battery-powered instruments in the stratosphere. On June 26, the craft landed on the snowy expanses of Baffin Island after a 4,000-kilometre journey. Piloted remotely by the French space agency (CNES), it flew between northern Sweden and northern Canada. This was a first. Usually, CNES uses the launch pad of the Swedish space station Esrange, near Kiruna. Balloonists inflate “open stratospheric balloons”, as they call them, to study the atmosphere. But they fly for no more than 12 hours, avoiding landing in the ocean, preferring the firm ground of Norway. “Staying in Sweden is even simpler for the formalities”, explains Valéry Catoire, researcher at LPC2E and principal investigator on the mission.
The summer solstice seemed to be ideal for such a long aerial crossing, according to a preliminary study envisaging the crossing of the Greenland and Labrador seas with this type of aerial vessel. It was also a favourable date for the winds, which flow at an altitude of 40 kilometers, from east to west. After August, these currents reverse, “in winter in Kiruna, we’re afraid of landing in Russia”, explains the researcher. “Here, we were sure of heading for Canada by following the horizontal layers of the stratosphere.” At 8:55pm on June 22, CNES released the aircraft, soaring perpendicularly over the peat bogs of Sami territory, for 4,000 kilometers of suspension. At the pace of a sparrow, the behemoth drifted for 92 hours over the Arctic. “The winds stayed in the right direction,” he adds.
The energy required to operate the instrumentation was also taken into account beforehand. Six square meters of photovoltaic panels produced the 1,000 W needed to power various scientific apparatuses and instruments. The installation rotated like a sunflower, following the perpetual path of the Sun.
A Swedish team observed the crystal clouds above the balloon (at an altitude of 80 kilometers) using their spectrometer. A wave sounder detected gamma rays. The University of Saskatchewan’s Osiris-3 spectroscope served as a test for a future space program. Carbon dioxide, nitrous oxide and methane – the atmosphere was continuously monitored, where satellites only pass through briefly during the day. “We were getting some data from the ground,” he recalls. “But the data is still in the black box, in Canada.”
At the height of Greenland, a terrestrial relay installed in Kangerlussuaq enabled us to stay connected with the nef. CNES pilots controlled the balloon’s height by releasing ballast or helium.
The Canadian space agency took delivery of the pod on June 26, 145 kilometers southeast of the town of Mittimatalik – meaning landing place in Inuktitut. “We were hoping that the gondola would land correctly so as not to lose the data”, explains the physicist. A helicopter picked it up on the 29th. A cargo plane took it to Iqaluit, 900 kilometers to the south. The cradle and equipment are now waiting to reach Montreal, before the transatlantic journey back to Europe.
Camille Lin, Polar Journal AG
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