NASA is firing lasers at trees from the International Space Station. for good reason

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more or less 400 kilometers Above our heads, the International Space Station (ISS) is responsible for expanding the limits of knowledge. On board is experienced with weightlessness, life support, propulsion, technologies are tested that may one day allow us to set foot on Mars or return to the Moon… And also, strangely enough, lasers are fired at the trees on Earth.

It sounds weird. And a little disturbing, too. But strange as it may seem, scientists have two good reasons to do so: expand our knowledge of the planet’s forests and improve strategies for capturing and storing CO2, essential if we want to meet our climate goals and avoid the worst consequences of global warming.

The initiative is part of the mission Global Ecosystem Dynamics Investigation —GEDI, for friends— and it is developed hand in hand by NASA and the University of Maryland with LiDAR laser technology. The objective, as detailed on your website, is to achieve high-resolution observations of the 3D structure of the Earth. Thanks to its reach, it can map even remote forest areas.

Good aim, better apps

“The ISS is making orbits along the Earth without stopping. And our GEDI satellite emits laser pulses all time –Adrián Pascual explains to the BBC, professor at the University of Maryland and part of GEDI—. When that pulse of energy reaches the Earth, it hits the first element it finds, which is the treetops, and continues to progress until it hits the ground.”

Thanks to its sensor, the team is able to measure the difference between the tops of the trees and the ground, a valuable piece of information that is used to study tree cover. “Thus, we are capable of estimating vegetation levels and that gives us an idea not only of the height of the forest, but also of its structural complexity”, highlights the expert in mapping and management of forest ecosystems.

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To carry out their work, the team works with a satellite that is about the size of a refrigerator, weighs about five hundred kilos and is attached to the ISS. During his studies he uses the lidar technology (Light Detection and Ranging), which we have already seen in other devices used by NASA to, for example, explore the remote South Pole of the Moon.

One of the keys to GEDI is that it applies LiDAR in a new way and with a new scope. “This technology had never been placed on a satellite, taken to the ISS and executed at more than 400 km high, specifically to monitor forests,” Pascual emphasizes to the BBC.

GEDI incorporates a total of three lasers that generate eight parallel observation tracks. When they work, each laser shoot 242 times per second and illuminates a point of 25 m on the surface of which the 3D structure is measured. Those “tracks” are in turn separated by 60 m along the track and a transverse distance of approximately 600 between each of the eight tracks.

Canopy Profile

Track showing the vertical distribution of vegetation.

Beyond giving us high-resolution laser observations of the Earth and accurately measuring the forest canopy, GEDI has valuable practical applications. Its technology improves our ability to study biodiversity and habitats or better understand water and carbon cycles.

“The data on the structure of the surface also they are of great value for weather forecasting, forest management, monitoring of glaciers and snow cover, and generation of more accurate digital elevation models.” details the team that supports the mission, and concludes: “GEDI provides the missing piece, the 3D structure, in NASA’s observation assets.”

“It advances applications that include water resource management, weather forecasting, forestry management and geomorphometry. Measurements of surface water height, ice, vegetation, and land surface can improve estimates of storm flooding risk, water supply, forest resources, and identify conservation priorities.”

Their work can also be of great help to us in the fight against global warming. After all, trees are one of our great allies in carbon capture and storage. “It is calculated more or less that a medium-sized tree, the most general thing that can be thought, fixes about 25 kilos of carbon dioxide per year”, Pascual points out to the BBC. Thanks to GEDI, we can estimate, for example, the amount of CO2 they store the planet’s forests.

His aim is not limited to areas already more or less known and well mapped by scientists; It also provides data on remote places, such as points in the Amazon where we do not know important issues, such as the height of the trees. The advantage that it takes from LiDAR allows us, among other things, to detect changes in biomass caused by illegal logging or the fire.

Despite its applications, GEDI could have the days numbered. The mission is scheduled to run until January 2023. From then on, another instrument will take its place on the ISS.

Given the prospect that your LiDAR will stop working in less than half a year and we may lose your valuable contributions a campaign has already been activated who asks to prolong the mission.

Images | Arnaud Mesureur (Unsplash) Y GEDI

more or less 400 kilometers Above our heads, the International Space Station (ISS) is responsible for expanding the limits of…

more or less 400 kilometers Above our heads, the International Space Station (ISS) is responsible for expanding the limits of…

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