The challenges of an alien spaceflight program-escaping super-Earths and red dwarf stars
(PHYSorg.com Space & Earth)

Since the beginning of the Space Age, humans have relied on chemical rockets to get into space. While this method is certainly effective, it is also very expensive and requires a considerable amount of resources. As we look to more efficient means of getting out into space, one has to wonder if similarly advanced species on other planets (where conditions would be different) would rely on similar methods.