UPHILL'S A BREEZE: Skiers and snowboarders like to slide down mountains, and often aren't excited by the need to use a chairlift or rope tow to be hauled up again. The UpSki is designed to make going up much more fun. It's effectively a round 4.5 Kg kite or parachute that the skier attaches to a harness on their body and that pulls them along. The kite is controlled by the attached short lines. The biggest problems seem to be that the sail can block the skier's view of what's ahead and there may be a risk of tangling skis in the lines.
A VIEW UNFOLDS: Optical telescopes need huge chunks of heavy glass to do their work. For telescopes that go into space the glass is fragile, bulky and very costly to deal with. DARPA's Membrane Optical Imager for Real-Time Exploitation program aims to use lightweight polymer membrane optics instead of glass. Membrane optics diffract light rather than reflecting or refracting it. In the past such membranes have been to inefficient to use but DARPA has been able to increase the efficiency to 55%. The membrane is etched with circular concentric grooves that focus the light onto a sensore which converts it into an image. The light weight of the membrans, which are about as thick as kitchen plastic wrap, could allow for giant space telescopes perhaps 20 metres across that unfold when they reach their destination. Etching grooves on plastic that thin will be a challenge.
LEND AN ARM:
When you exercise your muscles after an injury it would help to be able to see exactly the effect of each particular movement. The