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Aeolus Satellite Uses Powerful Ultraviolet Lidar to Measure Wind Speeds From Space

ESA’s biggest challenge was keeping the spacecraft’s advanced optics from fogging up

3 min read
Photo: ATG Medialab/ESA
Cyclone Watch: The data collected by Aeolus will improve the accuracy of weather forecasts.
Photo: ATG Medialab/ESA

It’s closing time for one of Earth observation’s most stubborn and critical data gaps: global wind speeds. A European Space Agency (ESA) satellite set for launch from French Guiana tomorrow—after nearly two decades of challenging engineering and a weather delaywill be the first to directly measure wind speed and direction, from Earth’s surface to the stratosphere.

Winds are key determinants of weather and climate, yet most wind data still comes from weather balloons. Readings from commercial jets supplement the balloons’ twice-daily samplings, along with estimates inferred from satellites that track moving clouds, atmospheric temperatures, and sea-surface roughness. The result is a patchy wind record that adds uncertainty to weather forecasts.

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Economics Drives Ray-Gun Resurgence

Laser weapons, cheaper by the shot, should work well against drones and cruise missiles

4 min read
In an artist’s rendering, a truck is shown with five sets of wheels—two sets for the cab, the rest for the trailer—and a box on the top of the trailer, from which a red ray is projected on an angle, upward, ending in the silhouette of an airplane, which is being destroyed

Lockheed Martin's laser packs up to 300 kilowatts—enough to fry a drone or a plane.

Lockheed Martin

The technical challenge of missile defense has been compared with that of hitting a bullet with a bullet. Then there is the still tougher economic challenge of using an expensive interceptor to kill a cheaper target—like hitting a lead bullet with a golden one.

Maybe trouble and money could be saved by shooting down such targets with a laser. Once the system was designed, built, and paid for, the cost per shot would be low. Such considerations led planners at the Pentagon to seek a solution from Lockheed Martin, which has just delivered a 300-kilowatt laser to the U.S. Army. The new weapon combines the output of a large bundle of fiber lasers of varying frequencies to form a single beam of white light. This laser has been undergoing tests in the lab, and it should see its first field trials sometime in 2023. General Atomics, a military contractor in San Diego, is also developing a laser of this power for the Army based on what’s known as the distributed-gain design, which has a single aperture.

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