A cable designed to drag space junk out of orbit has failed to deploy from a Japanese spacecraft. More than half a million pieces of debris are currently whizzing around our planet, including abandoned satellites and fragments of old spacecraft. They pose a danger to working satellites and new space vehicles. Scientists are working on a range of clean-up solutions, including cables, nets, harpoons, sails and robotic arms. All are designed to capture pieces of space junk and tug them down into Earth's atmosphere where they will burn up and disintegrate.

The spacecraft, whose name means stork in Japanese, will deliver some 5.9 tons of supplies, the heaviest load transported by a Kounotori ship. It is the largest among the cargo ships owned by Japan, the United States and Russia. Friday's launch, which followed Russia's failure in the launch of a Soyuz rocket carrying a Progress supply ship on Dec. 1, has raised the success rate of Japan's H-2 rocket launches to 97.3 percent. Of the 37 launches so far, all but one succeeded. In addition to water and food, Kounotori 6 will also deliver Japanese-made large lithium-ion batteries to replace batteries used at the ISS, experimental equipment for a new cooling system and equipment to measure cosmic radiation in real time.