NASA is thinking of going green. An environmentally friendly solid rocket fuel has passed the latest in a series of performance tests that mean it could ultimately replace aluminium-based fuel for future generations of space shuttle.
The new fuel is based on paraffin, and would produce only carbon dioxide and water. It is also non-toxic and would be safer than existing fuels, says Greg Zilliac of NASA Ames in California, because it could be shut off after ignition. But it wouldn鈥檛 have quite the same kick. 鈥淚t isn鈥檛 a Porsche, more like a Honda,鈥� he says.