ISEVEN DAYS

摘要

To revive the moribund US human spaceflight programme, NASA should plot a course for Mars, says the US National Academy of Sciences in a report published on 4 June. The report outlines plans for putting humans on Mars sometime between 2037 and 2050 at a cost of hundreds of billions of dollars. It criticizes the agency's current strategy of seeking to visit an asteroid put in orbit around the Moon, warning that it will end in the "loss of the long-standing international perception that human space-flight is something the United States does best". See go.nature. com/wp4zdl for more.