 It's a perspective that's thrilled astronauts since the beginning of manned spaceflight. And for over 25 years, crews have looked back in wonder from this unique vantage point, generating a variety of Earth imagery. Produced with motion picture and still cameras, as well as the shuttles on board video system, these images provide a visual record of how our planet is changing over time. And along the satellite data offers scientists in a number of disciplines a significant research tool. Oceanographers can look at currents from the right position with respect to sun angle. Detailed cloud patterns are captured for meteorologists, and geologists can see large areas with very high photographic resolution. This is almost a vertical shot of San Francisco. As we look down, you can very easily see the fault lines. So from a geological standpoint, this is a very, very good photograph. The sun angle is fairly low, and you can see exactly where the major minor faults are in the San Francisco area. Astronauts begin training in Earth observations when they enter the space program, so that by the time they fly, they are thoroughly familiar with the science and photographic techniques involved in the effort. This enables them to make real-time decisions about views from orbit, including capturing phenomena not on the original flight plan. All those events that cannot be predicted just happen. It is nice to have a crew, a set of human eyes to direct cameras and instrumentation to those sites in a very rapid response, and that's the value of the human being. Earth observations from the shuttle reveal dramatic changes on the face of our planet. This is a view of Lake Chad in Mauritania, seen over the nose of a Gemini spacecraft back in 1966. Shuttle crews flying over Central Africa in the 1985 timeframe saw Lake Chad looking like this. The only remaining water in the lake is that light gray patch at the upper end of the dark zone. This, of course, is simultaneous with the extensive drought conditions in Central Africa that underlies those very pointed human stories that we read about. The fragility of our atmosphere has struck all Earth-observing astronauts. You see how very, very thin a little coating it is compared to the rest of the size of the planet. It's not like the peel on a grapefruit or the peel on an orange. It's not even really like, to me, the shell on an egg for relative sizes. If anything, it's almost as if we're covered by that thin little membrane between the egg shell and the egg itself. That's the tiny little membrane of air and gases that keeps us all healthy. A major environmental concern today is the large-scaled burning and subsequent deforestation going on around the world. A number of shuttle crews have documented this activity. The intent is to recognize that there really are no sovereign boundaries in our environment, but that everyone, mankind as a whole, is affected by everything that each one of us do.