NASA photographer Joel Kowsky took a series of snapshots of the International Space Station (ISS) in silhouette transiting in front of the Sun at about 5 miles per second or 18,000 mph (29,000 kph).
At the time that Kowsky took that photo, astronauts Shane Kimbrough and Thomas Pesquet were outside the ISS on a spacewalk to upgrade the space station's power supply.
Image: Joel Kowsky/NASA