NASACast combines the content of all the NASACast subject area podcasts into a single omnibus podcast. Here you'll find the latest news and features on NASA's missions as well as the popular "This Week @NASA" newsreel.
Our virtual tour of the solar system continues with Mercury, the closest planet to the Sun. Since it’s tough to observe Mercury except at dawn or twilight, most of what we know about Mercury is from NASA’s Mariner 10 and MESSENGER missions.