This week, China launched a three-person crew into orbit to dock with the core module of its space station, still under construction. The building of the station, orbiting 236 miles above the earth, comes as the International Space Station is showing signs of aging. Host Marco Werman speaks with astrophysicist Jonathan McDowell, who says the Tiangong space station is small by ISS standards, but an important step for China’s human space program.