Reports from the edge of science
Staying power for discreet Drones
The key to fielding tiny unmanned aerial vehicles for surveillance is keeping them undetectable. That’s why designers prefer to use fuel cells to power such UAVs – they are much quieter than internal combustion engines and have a minimal heat signature that cannot be detected with thermal imaging scopes. Battery power is usually too weak to keep even a small aircraft aloft very long or to match the speed of quickmoving targets. Scientists at the US Naval Research Laboratory and fuel cell maker Protonex Technology have created the Experimental Fuel Cell UAV, a small, folding-wing system designed to loiter at 55 km/h and dash at over 90 km/h. In recent tests, the 1,8-metrelong XFC managed to stay aloft for more than 6 hours, powered by longendurance hydrogen fuel cells.
New car for Mr Magoo
Cars could become advanced enough to be driven by people who can’t see. Student researchers at Virginia Tech in the US retrofi tted a four-wheel dirt buggy to be driven by blind drivers. Test drivers controlled the vehicle using laser rangefi nders as “eyes”, voice controls and a tactile map, while continuing to operate the brakes and accelerator. In tests on closed courses, blind drivers out-performed sighted drivers using the same vehicles, since the sighted drivers were more hesitant to trust the car’s feedback.
2 400 kilograms of explosive
The Massive Ordnance Penetrator is designed to destroy deeply buried bunkers or hardened facilities. With a weight of 14 000 kilograms (including more than 2 tons of explosives), the precision-guided weapon would be the biggest conventional bomb the United States has ever fi elded. The US Air Force is asking for funds to accelerate the development of the weapon, so that MOP could be available for use by next July.
Galaxy cluster smashes distance record
The most distant galaxy cluster yet has been discovered by combining data from Nasa’s Chandra X-ray Observatory and optical and infrared telescopes. The cluster, known as JKCS041, is located about 10,2 billion light years away, and is observed as it was when the Universe was only about a quarter of its present age.
30 revolutions a minute
Muscles atrophy in the absence of gravity, posing a sizeable problem for future astronauts on a year-long mission to Mars. However, recent studies indicate that an hour a day on an onboard centrifuge could mitigate the problem. Nasa-supported researchers at the University of Texas Medical Branch at Galveston confi ned 15 volunteers to zero-gravity-simulating bed rest for three weeks. Eight of them were spun an hour a day in a centrifuge and maintained normal rates of protein synthesis in their thigh muscles, while rates for the bed-ridden, no-spin group dropped by almost half. Life science researchers in Galveston are seeking the right mix of food supplements, exercise and centrifuge spins to preserve astronauts’ muscles – and they say that a similar formula could help elderly patients on Earth during hospital stays.