Air-dropped javelins used to monitor Antarctic glacier

BBC : The British Antarctic Survey has developed a system of sonobuoy-like javelins that can be dropped from airplanes to place monitoring equipment in otherwise hard-to-reach places. Currently, the devices are deployed on Pine Island Glacier in Antarctica. The glacier is fast moving and crossed by chasms and precipices that make ground access impossible. It is also responsible for almost 10% of the ice that flows off the west side of the continent. The javelins are dropped from a plane with small parachutes and hit the ice at 50 m/s. Almost 3 m long and weighing 10 kg, each device has fins that prevent it from burying itself in the ice and satellite antennae and monitoring equipment that include GPS to track the glacier’s movement. Because the javelins are built to withstand the forces of the impact, 25 of the 33 that were deployed are operational; they are expected to last for up to two years. The glacier is of significant interest because satellite and aerial observations have recorded a recent thinning of the ice and an increase in movement speed. Being able to monitor the glacier will allow researchers to better understand the effects of global warming on Antarctic ice.