WHEN NASA's record-breaking hypersonic X-43A aircraft dived into the ocean last week, the space agency's budget for hypersonic civil aviation research sank with it. The technology will instead wind up at the Pentagon, where it will be used to build a bomber that can attack targets anywhere in the world within 2 hours.

Last week's Mach 9.8 flight capped a 40-year quest to demonstrate hypersonic flight. "We showed that it's real," says Chuck McClinton, technology manager for the Hyper-X programme at NASA's Langley Research Center in Virginia.

While the flight garnered newspaper headlines of a future in which hypersonic aircraft fly civilians from London to Sydney in 2 hours, the stark reality is that NASA cannot afford to undertake the research to make it possible. Its focus is now firmly on exploring the moon and Mars. NASA engineers will merely support hypersonic development at the Air Force Research Lab and ...