Astronaut photography of the Earth from the International Space Station has achieved spatial resolutions of less than six meters, an analysis of more than 13,000 images has shown. This means scientists can use photographs taken from the space station to study changes that are occurring in very small features on the Earth's surface.
The results of this study are discussed in an article in the April 23 edition of the American Geophysical Union journal Eos Transactions.
"The sharpness of the photographs taken by the station astronauts surprised both them and the scientists on the ground," said Dr. Julie Robinson, lead author of the paper and a Lockheed Martin scientist in the Earth Sciences and Image Analysis Laboratory at NASA's Johnson Space Center in Houston. "It has really changed our view of how much detail humans can photograph from orbit."
The first three resident space station crews took 13,442 images of the Earth using digital still cameras, 35-mm cameras, 70-mm cameras and a variety of lenses. Crewmembers were able to produce higher-resolution photographs with the high-magnification lenses by learning to compensate for the relative motion of the Earth below while pointing cameras through a specially built window in the station's Destiny Laboratory.
"Astronauts now consciously track the ground when photographing the Earth," said Dr. Cynthia Evans, co-author of the paper and the manager of the Earth Sciences and Image Analysis Laboratory for Lockheed Martin Space Operations. "Their digital cameras provide instant feedback, allowing crewmembers to refine their tracking and focus techniques. Because each crew has demonstrated this capability, we can reliably plan for scientific studies that require more detailed imagery that might not otherwise be available to Earth Science researchers."
"Since the birth of the space program, astronaut photographs of the Earth have engaged the public," Robinson said. "Scientists also use these photographs as valuable records of the state of the Earth. With new digital technologies, and high-resolution capabilities, astronauts on the International Space Station continue to acquire Earth imagery that has scientific relevance."
A searchable database containing more than 30 years of astronaut photography is available on the Web here.