RELEASE NOTES

摘要

As commander of the International Space Station, astronaut Chris Hadfield tweeted dozens of times a day. It was a far cry from his first mission in 1995: "Ham radio and film pictures-that was social media," he says. Watching Earth from 250 miles up has convinced Hadfield that we need to treat our planet with the same care we give our spaceships. He argues that point on page 33.