Telegraph: Asteroids may prove to be “oases” for future space missions. They are potentially a rich source of natural resources, such as water and metals like iron, gold, and platinum. Water can be broken down into hydrogen and oxygen, which can be used in rocket fuel; metals can be used to build and repair equipment. Having to launch those materials from Earth costs about $10 million per ton. To examine near-Earth asteroids and collect samples, a US company, Deep Space Industries, is proposing to start sending probes by 2015. Besides gathering data concerning asteroids’ potential resources, the probes could also provide information useful for science and for planetary defense. Not all asteroids will work, however: Although Asteroid 2012 DA14—due to pass by Earth later this month—could contain as much as $200 billion worth of materials, its trajectory would make it prohibitively expensive to send a probe there.