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turgid writes:
The Guardian reports that an Egyptian blogger has been sentenced to four years in prison for insulting Islam (3 years) and the country's president, Hosni Mubarak, (1 year) in the country's first prosecution of a blogger.
Amnesty International has more information.
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turgid writes:
The Hindustan Times and New Asia Times report that the Indian Space Research Organisation plans to land an Indian on the Moon by 2020.
First, experiments will be conducted to launch and recover a capsule using a Polar Satellite Launch Vehicle (PSLV). Later, manned orbital missions will be launched on a GSLV Mark II rocket, initially for a day, but eventually lasting a week or more. Expeditions to the Moon are expected to last 15 days to a month.
The ISRO sees human space exploration as vital to India's technological and economic develpment and argues that the human brain is a far superior resource to have on a spacecraft than any robot or other scientific instrument.
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turgid writes:
The Engineer Online reports that British spacecraft engineer Roger Shawyer has invented the first propellentless, electrically-powered rocket thruster, which takes advantage of the relativistic properties of electromagnetic radiation.
The device consists of a conically-shaped copper chamber into which microwaves are pumped from an ordinary magnetron (similar to those found domestic microwave ovens). The chamber's size is chosen to allow resonance of the microwaves.
Since the ends of the chamber are different sizes, so it goes that the velocity (group or phase is not made clear) of the microwaves is different at either end. The waves impart momentum the ends of the chamber, since photons have momentum and are bouncing off the metal, but since the velocities are different at each end, so is the momentum transferred. This results in a difference of momentum transferred across the length of the chamber, and a net force is exerted in the direction of the larger end, i.e. thrust.
So far, using a few kilowatts of power and a table-top chamber, Shawyer has been able to reliably and reproducibly demonstrate a thrust equivalent to a weight of a few tens of grams. This compares favourably to the latest in ion engine technology. The advantage is that Shawyer's "EmDrive" reqires no reaction mass, only fuel and an engine to generate the electricity to drive the magnetron: the same thust with a tenth of the weight.
To increase the thrust enough to levitate a car, for example, Shawyer reckons he'll need to construct a superconducting chamber which will reduce losses to the chamber walls. Unfortunately, he hasn't figured out how to make it efficient under large accelerations, so initial applications will be limited to satellite attitude control and maybe even levitation of vehicles.
