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Nasa successfully tests first laser-powered aircraft
EVER since the dawn of powered flight, it has been necessary for all aircraft to carry onboard fuel – whether in the form of batteries, fuel, solar cells, or even a human “engine” – in order to stay aloft.
But a team of researchers from Nasa’s Marshall Space Flight Center, Nasa’s Dryden Flight Research Centre, and the University of Alabama in Huntsville is trying to change that.
They have now chalked up a major accomplishment ... and a “first.” The team has developed and demonstrated a small-scale aircraft that flies solely by means of propulsive power delivered by an invisible, ground-based laser. The laser tracks the aircraft in flight, directing its energy beam at specially designed photovoltaic cells carried onboard to power the plane’s propeller.
“The craft could keep flying as long as the energy source, in this case the laser beam, is uninterrupted,” said Robert Burdine, Marshall’s laser project manager for the test. “This is the first time that we know of that a plane has been powered only by the energy of laser light. It really is a groundbreaking development for aviation.”
The plane, with its five-foot wingspan, weighs only 11 ounces and is constructed from balsa wood, carbon fiber tubing and is covered with Mylar film, a cellophane-like material. Designed and built at Dryden, the aircraft is a one-of-a-kind, radio-controlled model airplane. A special panel of photovoltaic cells, selected and tested by team participants at the University of Alabama, is designed to efficiently convert the energy from the laser wavelength into electricity to power a small electric motor that spins the propeller.
The lightweight, low-speed plane was flown indoors at Marshall to prevent wind and weather from affecting the test flights. After the craft was released from a launching platform inside the building, the laser beam was aimed at the airplane panels, causing the propeller to spin and propel the craft around the building, lap after lap. When the laser beam was turned off, the airplane glided to a landing.
Photosynthesis puzzle solved
A complete molecular-scale picture of photosynthesis, how plants convert sunlight to chemical energy, has been obtained, offering new insights into animal metabolism as well.
Biologists have determined the structure of the cytochrome, a protein complex that governs photosynthesis in a blue-green bacterium.
According to Professor William Cramer of Purdue University in the US, the discovery is a great leap forward in the understanding of photosynthesis.
The researchers say their work does not have any immediate applications, but it does provide an insight not only about a chemical process crucial to all life, but also about how cells handle and distribute energy.
The key to the discovery was being able to crystallise cytochrome molecules, so that they could have their structure determined by an X-ray probe.
“Now that we can examine these proteins closely with X-ray crystallography, it could lead to knowledge about how all cells exchange energy with their environment.”
The molecular layout of the cytochrome gives some indication of the complex motion of electrons and protons across the bacterium’s cell membrane, the boundary between the cell and its environment.
The cell that provided the proteins for the team’s work was a cyanobacterium, a single-celled organism commonly found in hot springs.
The particular cyanobacterium used in these studies was isolated by Swiss researchers at a hot spring in Iceland. While animals do not employ photosynthesis, their cells do make use of similar proteins for respiration. The similarities could lead to a better understanding of our own metabolic processes.
“The differences can now be explored more easily,” says Cramer.
Sandy grains circle star
The first direct evidence of a sandy disc surrounding a star just like our Sun has been obtained by Japanese astronomers.
It is a very good indicator that planets like Earth could be forming around the star which is 160 light-years away in the constellation Taurus.
The discovery was made using a new infrared camera and spectrometer on the Subaru Telescope in Hawaii.
Although astronomers had suspected the presence of crystalline silicates in discs surrounding young Sun-like stars, previous generations of detectors were not sensitive enough to find them.
The Japanese team says its success ushers in a new era in infrared astronomy and the study of planet formation.
The discovery is important because most of Earth’s crust is made of silicates, minerals composed of silicon and oxygen.
Finding them around other Sun-like stars suggests that small rocky worlds like Earth could be forming there as well.
Silicates come in two forms: crystalline and amorphous. Crystalline silicates have symmetry in their structure, amorphous minerals do not.
“Now that we know that the crystalline silicate exists, our next challenge is to observe how the crystalline silicate is distributed in space,” says Mitsuhiko Honda of the University of Tokyo.
“We want to understand the processes taking place in the proto-planetary disc that lead to the formation of crystalline silicates in the first place.” — Dawn ScienceDotcom Report
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