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Solar Plane With Global Aims Makes First Flight

Solar Impulse 2 makes two-hour inaugural flight in Switzerland

1 min read
Solar Plane With Global Aims Makes First Flight

Solar Impulse 2, a solar-powered airplane built to fly around the world next year, took its first test flight yesterday morning. Test pilot Markus Scherdel took off in the plane at 5:38 Central European Time from Payerne airport, Switzerland, and landed at 7:52, according to the Solar Impulse website. Scherdel reported some unintended vibration but the team attributes it to the landing gear.

Solar Impulse is a project spearheaded by Bertrand Piccard, an adventurer who circumnavigated the Earth in a hot air balloon in 1999, and is funded by a large private consortium. The consortium built a prototype, dubbed Solar Impulse 1, in 2009. That plane achieved solar-powered flights across the Mediterranean and across the United States with four stops. It also flew for an entire night, using energy it had captured during the previous day's flight (see also IEEE Spectrum'sQ&A with a Solar Impulse rep during the first 24-hour solar-powered flight).

Solar Impulse 1's bigger, more advanced sibling weighs 2300 kg, of which 633 kg are lithium batteries for storing the energy generated by the plane's 17 000 solar cells. The batteries have new electrolytes intended to achieve an energy density of 260 watt-hours per kilogram, and the plane uses a new kind of carbon fiber that keeps its weight down. The plane takes off at bicycle speeds, which is handy since its wings, which span 72 meters, need spotters on bicycles to ensure that they do not strike the runway.

The team will spend this summer testing and certifying the new model ahead of next year's attempt.

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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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