SpaceNuclear fuel for spacecraft set to run out in 2018 The nuclear isotopes that power missions like Cassini are leftovers from Cold War reactors and are set to run out in a decade if no more are produced ¿ìè¶ÌÊÓÆµ
SpaceSpace sail could bring used rockets back to Earth A sail that increases atmospheric drag could force rocket stages out of orbit more quickly, reducing the problem of space debris ¿ìè¶ÌÊÓÆµ