ELECTRONIC	h   t   t   p   c o l o n   s l a s h   s l a s h   a s t r o b i o l o g y dot n a s a dot g o v   s l a s h   a s t e p   s l a s h   a b o u t   s l a s h   b i l l i n g s	http://astrobiology.nasa.gov/astep/about/billings	1