Patterns and colors of light seen from space tell us a lot about who and where we are on Earth.">
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In This Issue
From the APPEL Director—Project Management Trends and Future Reality
The Knowledge Notebook—On Not Going It Alone: No Organization Is an Island
Space Exploration in the 21st Century: Global Opportunities and Challenges
Interview with William Gerstenmaier
Sharing Knowledge About Knowledge
NextGen: Preparing for More Crowded Skies
Anatomy of a Mishap Investigation
Are We Alone? Answering This Question Is Not a Lone Venture
NASA Past and Future: A Personal Memoir
The Next Big Thing Is Small
Cities at Night: An Orbital Perspective
Petrobras and the Power of Stories
Typical western U.S. cities, Las Vegas (top) and Los Angeles (bottom), are defined by yellow-orange sodium vapor–lit streets in grids. Airport runways stand out as dark lines where, surprisingly, it is better to land an airplane on a dark runway than a well-lit one. At the edge of town, the lights abruptly fade into the surrounding desert. The "Strip" in Las Vegas is probably the brightest spot on Earth. (Click each image for close-up)
The improvised tracker placed on the US LAB module window. (Click image for close-up)The mount's precision gimbal motions could be used to eliminate the effects of orbital motion only if a precise and smooth method of panning could be improvised. I mounted a long, threaded bolt on the IMAX platform so that it pushed against a plate and smoothly moved the platform in one direction when it was rotated. This direction of motion was then aligned with that of orbital motion so the mount would pan and cancel out the effects of orbital motion, at least long enough for a few exposures. A variable-speed drill driver was used to rotate the bolt; the rotation speed, and hence pan rate, could be varied by how far the drill drive’s trigger was pulled. I then attached two cameras to the mount, one with a long telephoto lens to act as a spotting scope and one with a medium-focal-length lens to take the photograph. Orbital motion was canceled by first looking through the spotting-scope camera and varying the rate of bolt rotation by squeezing the trigger until the image of the city below stood stationary on the camera’s focusing screen. Then I took an image with the second camera using a cable release.
Donald Pettit using one camera to track city lights and taking the image with a second camera via a cable release. Amateur astronomers will recognize that what was improvised out of spare parts on the space station is no more than what they have been doing for decades with a simple tracking system dubbed a "barn door" that consists of two boards, a piano hinge, and a manually rotated bolt. The difference between handheld images of cities at night and those made with the tracking system is striking. (Click image for close-up)We are in the process of merging these astronaut-taken images of cities at night with the popular nighttime Earth images from the Defense Meteorological Satellite Program (DMSP). The DMSP images have near-world coverage but at a much lower resolution (about 3 kilometers in black and white) than the astronaut images now coming from the space station. A joint NOAA–NASA satellite under development will be optimized to take full-color, high-resolution images of nighttime Earth and eventually render this initial astronaut effort obsolete. Such is often the course with exploring a frontier. The special eye of humans pioneers the initial phase of discovery followed by the development of highly specialized machines that result in a more complete and better set of collected data.
Above: Two images of Montreal, Canada, taken from the International Space Station. The best handheld image is shown on the left, and on the right is an image taken with the improvised barn-door tracker. Once this technique of operating the barn-door tracker was refined, astronauts used it to take images all over Earth. The resolution of ground objects in these new images is about 60 meters, and the current database of cities at night is now at about eight thousand, gathered by many crews.
Above: Chicago (left) and Tel Aviv with Jerusalem in Israel (right). A grid of north–south, east–west streets typifies U.S. cities, whereas Europe and the Middle East show a tangled pattern of lighting.
Above: São Paulo, Brazil (left), a major urban area, shows blue-green (mercury-vapor lighting) in the older original town center and yellow-orange (sodium vapor) in its newly growing borders. Tokyo (right) typifies the blue-green lighting of Japan's major cities. The dark spot in the center of town is the Emperor's Palace; Narita Airport terminal is the bright spot to the east.
Above: Antwerp, Belgium (left), with Brussels at the bottom edge, and Milan, Italy (right). Spider-web networks of streets typify the older European cities.
Above: El Paso, Texas (left), bordering Juarez, Mexico. El Paso appears with a grid of illuminated streets with relatively dark areas in between. Juarez displays scattered light in an area defining the city limits, matching the urban area "yellow zone" printed on an atlas. The square of the District of Columbia (right) is clearly defined with an east–west dark line identifying the National Mall with the Capitol seen as a bright spot on the east end and the Lincoln Memorial on the west. Center is the Washington Monument, and the Jefferson Memorial is seen as a spot of light on the south side of the bay.
Above: A mosaic from the southern tip of South Korea (upper left)
to the northern Kyushu coast of Japan (lower right). Fishing boats
using bright Xenon lights are in the sea between South Korea and
Japan with some lights blurred by sea fog. Bright Xenon lights are
used at nighttime to lure squid into nets. (Click image for close-up)
Donald Pettit has logged more than 176 days in space and over 13 extravehicular activity hours. He lived aboard the International Space Station for five and a half months in 2002–2003 and, in 2008, was a member of the STS-126 crew.