We now present a gallery of exemplar photos, taken from representative Shuttle and other space missions. Some computer screens pair these images side-by-side but, small screens may display one above the other. Each one has a brief description.
Let's start with a sequence showing active and recent volcanoes on three continents. In the first pair, on the top is a vertical photo taken during STS-59 that shows a snow-covered island in Russia's Kamchatka Peninsula (far east Siberia) that has a volcanic caldera at each end, both with a central stratocone. Below it is an oblique scene that traces a long plume emanating from the Kliuchevskoi volcano in that peninsula during an active eruption.
Mount Saint Helens, in southern Washington State, erupted catastrophically in 1980. Astronauts photographed it in 1994, with a Nikon 300 mm lens, during the STS-64 mission, clearly showing the persistent aprons of ash deposits, despite considerable reforestation, lobes of lahars (ash-mud flows), and the great gap where part of the mountain was blown away.
It is interesting to place Mt. St. Helens in context with two other great stratovolcanoes in the Cascade Mountains of the western U.S. These two Shuttle views, one an oblique, false-color IR picture (looking northwest) and the second, a near vertical, natural-color shot, show Mount Saint Helens (MSH) to the west and Mounts Rainier and Adams to the east, all snow-capped. Indeed, MSH is the only volcano that is significantly offset from the main line of the Cascadian volcanic activity. Note the clear-cutting patterns in the forested countryside.
A volcano known as the Pic Tousside, in the Tibesti Mountains in the Sahara of Chad (Africa), is noteworthy because of the insect-like shape created by several recently erupted basalt flows:
Astronaut photography and geostationary satellites have depicted large areas of the global surface. Observe, on the top, a southwest-looking STS photo of the Great Lakes in the northern U.S. and adjacent Canada. Compare this with a scene extracted from a Nimbus AVHRR false-color image that covers all of these lakes (state and province boundaries are superimposed). Test yourself in identifying each of the Great Lakes.
We view cities in context with their surroundings in STS pictures. Below, the top view (STS-56) is Tokyo Bay in Japan. Tokyo is in the upper left, and Yokohama is in the lower left. On the right (east) side of the bay are built-up areas that include large landfills bounded by retainer walls, which hold ship docks. Compare Tokyo's visibility with the winter scene (STS-60) of Montreal in Quebec, Canada (bottom), in which cleared streets stand out against the snowscape, similar to a dusted fingerprint.
In the late 1990s, a new variant of Shuttle Photography was introduced: the EarthKam program. Here the astronauts took photos of targets that were preselected by America's K-12 grade students. The scene below is an example. It shows the Cape of Good Hope at the southern tip of Africa (south is to the right). The Hottentot Holland Mountains lie above the town of Strand. Note the column of smoke from a possible forest fire.
Another EarthKam example, also from South Africa, shows a region where this country meets Mozambique (right), along with the untouched Kruger National Park, a reserve for wild animals that is a popular "safari" tourist attraction. To the left are patches of landuse caused by recent resettlement of black Africans during the later stages of apartheid. This grouping is known as the Gazankulu Homeland, actually a series of "ghettos" that are now being rejuvenated after the addvent of self-rule in South Africa in which the dominant black population has assumed a leading role in governance.
A very large number of EarthKam images are Net accessible at the ISS EarthKam site.
Astronauts have taken some remarkable pictures from space in the dead of night. In one example, from the Shuttle, the collective lights of cities and towns around San Francisco Bay outline it in orange.
Although the next image is not a photograph, it ties in with the above San Francisco at night photo, but on a grandiose scale. The Defense Mapping Satellite Program (DMSP) is operated by the U.S. Air Force. One of its sun-synchronous, near-polar satellites took (from an 625 km [516 mile] altitude) nighttime images of the U.S. using a channel operating between 0.4 and 1.1 Ám. Under cloudfree conditions in December 1986, the scene mosaic shows only those areas large enough to produce a concentration of light from street lamps, etc. See if you can locate the region in which you live, using the pattern of lights from metropolitan areas near you, Can you tell what accounts for the numerous linear patterns developed over most of the U.S.? How many areas of concentrated light can you identify as urban centers?
It is instructive to compare the above DMSP image taken in 1986 with another, covering the U.S, southern Canada, the Caribbean, and Central America, and the northern part of South America, taken by a later DMSP in the year 2000. The increase in urban and town development in the western U.S. is especially noteworthy.
These images are realtime, actual portrayals of what is present at the surface of the U.S. and Canada. Satellite imagery is helpful in assessing population density and distribution. This information source has been used to provide auxiliary input into the making of a population density map for the United States (including Alaska and Hawaii) and Canada that was made public about 2 weeks (late October 2006) after the U.S. passed the three hundred million mark in its citizenry. Compare this map with the DMPS image above.
The European continent, and the Mediterranean lands especially, is heavily populated. One would expect many urban and regional centers to be notably "lit up" and thus easily recognized in night imagery. Examine this DMSP image of this part of the world and see how many specific cities you can place and identify.
Since Shuttle astronauts encircle the Earth in less than 2 hours and do this repeatedly during any 24-hour time stretch at a ground reference point, they should in this period see a number of sunrises and sunsets. This image of Europe and North Africa shows the sharp terminator marking dusk at some particular moment. Behind the still daylight area, the lights of Europe-Africa to the east have been switched on:
On a truly grand scale, the DMSP has covered the Earth under cloudfree conditions enough times now to allow production of a relative night light brightness map for all the continents of the World. Using images obtained at different times, and then mosaicked, this composite amounts to a map that also indicates the distribution of population densities. Japan seems to have the highest density, followed by Europe and the eastern U.S..
We have reproduced this image as a very large version of this global night view of the Earth's lands and seas that can be accessed by clicking here. This is a recent DSMP composite image. It is big enough for you to see details not evident or hard to discern in the above image. Note the tendency for high population densities along coastal regions.
The Shuttle crews always look for terrestrial phenomena around, rather than on, the Earth. Here is a view, from STS-45, of the aurora borealis (also known as the Northern Lights) appearing as spectacular light bands, caused when electrons and other particles from the solar wind strike atoms in the outer atmosphere (see page Intro-1).
A rich source of a plethora of astronaut photography can be visited at the Johnson Space Center's Earth from Space Web site.
The Russian cosmonauts have also had a long-standing program for acquiring space photos. In recent years, they operated the Kosmos KVR-1000 camera on their MIR Space Station. Pictures, available commercially, using this camera can have spatial resolutions as high as 2 m (about 6.6 ft). An example of the sharpness achieved in such photos is this view of part of downtown Atlanta, Georgia:
Astronaut Shannon Lucid, participating with the Russians on MIR for an extended mission, took a large number of photographs of preselected targets of special interest. Two that are especially informative are scenes of the inland delta of Niger, in Africa. Almost every year there is enough rain to temporarily fill a basin along the Niger River as shown in the top photo. But, the arid, hot summer climate quickly dries this oasis of water leaving the rather desolate scene shown in the bottom photo. Note the sand dunes.
In one sense, the astronauts/cosmonauts are the "ultimate tourists" who take special pleasure and meaning from their photography activities while in space. Many of their targets are pre-selected but some are genuine targets of opportunity. Now, with the realization of the International Space Station (ISS) as a functioning platform, many new opportunities will be presented. The ISS has a Science Laboratory Module that includes a dedicated window, with special optical quality glass, through which photographs are being obtained. Here is a view of the ISS with its photo-window, taken soon after the module was attached in mid-February 2001.
And here is a photo taken in February, 2001 through this window. The scene is the ever-popular target - San Francisco - as it appears from 166 miles away.
Even more impressive is this ISS photo of Niagara Falls, near Buffalo.
A scene that has fascinated the astronauts and is thus represented by several photos is the Belasaka Estuary in Madagascar (see also page 17-4). Here is one ISS version:
The quality and sharpness of astronauts photos has steadily improved with better (now digital) cameras. The scene on the top is a November 24, 2004 ISS photo of Lake Sambhar in the Rajashan area of northwest India; on the bottom is an IKONOS view of the Glen Canyon Dam at Page, Arizona (a few miles from the Utah border) which produces Lake Powell along the Colorado River; the resolutions in both are less than 5 meters.
Here is another example of recent photo sharpness. Taken in the summer of 2008, this colorful scene shows the western end of the Florida Keys. These small coral reef islands are known as the Dry Tortugas (a tortuga is the spanish word for "turtle").
Photos both of the ISS and its crews and of ground scenes can be found at the International Space Station gallery. What comes up first is a banner and an Index arrow which when pressed gives a menu of imagery from all the astronaut programs. Click on the Station button to access ISS photos. But, if curious, click on any of the other buttons to see their contents.
The topics summarized in this Section should, first, point to the unique role of trained humans in space and, second, underscore the value of hand-held photography. A third advantage of pictures from manned missions is their low cost and ready availability compared to those from automated observation satellites like Landsat, SPOT, and similar space imagery, that generate expensive and sometimes proprietary products. Fourth, their natural color and their obliquity make many hand-held pictures generally well-suited to educational use, providing easily understood views of the Earth from orbital altitudes. Finally, the photography stands as a record of long-term changes (going back to the 1960s) of the Earth's surface, whose appearance, as well as its physical structure are continuously changing, sometimes from minute-to-minute.