Able to shoot 10 000 times per second and detect a difference of level of only a few millimeters, the laser onboard the satellite, ICESat-2 is the most advanced ever placed in orbit. The satellite a half-ton needs to be powered up on Saturday by a rocket Delta II since the base Vandenberg of the US Air Force in California. It’s mission will be to reveal the full extent of the melting of the ice on an Earth that heats up.
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This mission is “extremely important to science,” noted Richard Slonaker, program manager, ICESat-2 for Nasa. Because for nearly ten years the agency no longer had an instrument in orbit to measure the thickness of the surface areas covered by ice throughout the planet. With ICESat-2, the measures will be “extremely accurate”, the thickness of a pencil, has insured a member of the team, Kelly Brunt.
to Better understand the rise of the oceans
The previous mission, ICESat was launched in 2003 and was completed in 2009. Thanks to it, scientists have learned that the ice pack is affinait and surfaces covered with ice were to disappear in coastal regions of Greenland and Antarctica.
Since then, surveys have been carried out through a plane in the framework of a mission called Operation IceBridge, which flew over the Arctic and the Antarctic. “Height measurements and data on the evolution of the ice has been harvested, explained Nasa. But an update is urgently needed.
The melting of sea ice could threaten a quarter of the world population. On the occasion of the world climate Conference in Geneva in early September, the WWF has published a study on the consequences of the warming of the Arctic.
REUTERS/Denis Sarrazin/Center for Northern Studies
The increasing use of fossil energy sources by mankind leads to a constant increase of the emissions of greenhouse gases, considered the main responsible for climate change. The average global temperature increases year after year. And the four warmest years in modern times have been recorded between 2014 and 2017.
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The all-new ICESat-2 is expected to help scientists to understand the magnitude of the contribution of melting ice to rising oceans, while the phémonème increases with the decrease of the ice layer in the Arctic and in Greenland. Hundreds of millions of people in coastal regions around the world are threatened.
measures taken every 70 centimetres
“We’re going to be able to look at specifically how the ice operates on a single year,” noted Tom Wagner, a researcher of the programme cryosphere (ice land) of the Nasa. Combine these records with those collected over the years should give a boost to the understanding of climate change and improve the projections on sea-level rise, he added.
The ICESat-2 is equipped with two lasers – one spare just in case – much more sophisticated than the model at the edge of the previous mission. Despite its power, the ray will not be hot to the point of melting the ice from the observation post orbital deployed some 500 kilometres above the Earth, noted Nasa. It will draw 10 000 times per second, as against forty times to its predecessor, which will provide data much more detailed. Measurements will be taken every 70 centimetres on the path of the satellite.
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“The mission will collect enough data to quantify the annual changes in thickness of the layer of ice in Greenland and in Antarctica, even if it is only four millimeters to a penalty,” said the us space agency. In addition to the thickness and the surface area of the ice layer, the laser will also measure the slope on which it is laid.
“one of The things that we’re trying to do is to decipher the changes that are happening inside the ice, and this will greatly improve our understanding in this matter, in particular in the regions where we do not know well yet how they evolve,” explained Tom Wagner, citing the great depths of the Antarctic as one of these mysterious worlds.
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The mission is expected to last three years, but the satellite has enough fuel to last for at least a decade, if its leaders decide to extend its life.