Astronaut Photography

Background
Astronauts have used hand-held cameras to photograph the Earth for more than 30 years, beginning with the Mercury missions in the early 1960s. Crew members on NASA missions have taken nearly 400,000 photographs with Hasselblad, Linhof, Rolleiflex, and Nikon hand-held cameras.

Venice as photographed by crew members aboard Space Station Alpha

Astronauts are trained in scientific observation of ecological, geological, geographic, oceanographic, environmental, and meteorological phenomena. They are also instructed in the use of photographic equipment and techniques. Preflight training helps the astronauts make informed decisions on which areas and phenomena to photograph. Specific areas of scientific interest are selected before each flight by a group of scientists. The astronauts receive intensive training, in-flight aids, and messages from the ground to help them locate these sites that are of scientific interest.

An astronaut trained in the Earth sciences can rapidly identify and photograph interesting and unexpected phenomena, interpret what has been observed, and modify planned activities as needed. Near real-time information exchange between the crew and scientists expedites the recording of dynamic events of geological, oceanographic, environmental, and meteorological importance. Critical environmental monitoring sites are photographed repeatedly over time; some have photographic records dating back to the Gemini and Skylab missions. Earth limb pictures taken at sunrise and sunset document changes in the Earth’s atmospheric layers. Photographs of hurricanes, thunderstorms, squall lines, island cloud wakes, and the jet stream supplement weather satellite images by offering high-resolution stereoscopic coverage of such phenomena.

Astronaut photography provides several unique contributions to the range of Earth Science information available from NASA (Lulla et al. 1996). First, the images are readily accessible to the public — they are non-proprietary, can distributed in digital form on the Internet (at the Gateway to Astronaut Photography of Earth), and are in a real-color photographic form that is easily interpretable by non-scientists. Second, the unique aspects of handheld data make it possible to view the Earth in ways that are not common from other sensors. In addition to images looking directly down at the ground, astronauts can look obliquely at haze in the atmosphere, or use sunglint to view water boundaries and wave features. Third, because the photographs are in the public domain, they provide a low-cost alternative data source for cases where other satellite imagery cannot be acquired or is not sufficient. Such cases often include studies in developing countries, in areas that have not usually been targets for major satellites, needing supplemental low-cloud data, requiring a time series, or requiring a large number of images.

Photographic Characteristics
Variability is both a key feature and a data extraction challenge for astronaut photography of Earth. Because astronauts use a variety of lenses and look angles, different cameras and films, and take their images from different altitudes, there is not a single spatial resolution for the imagery. Most nadir-viewing (directly down at the Earth) images have spatial resolution of 20 to 60 m. However, recently higher magnifications have been used successfully with spatial resolutions less than 6 m. At the Gateway to Astronaut Photography of Earth, NASA provides interactive tools that can be used to estimate spatial resolution for a specific image (Robinson et al, in press).

Summary
Astronaut orbital photography fills a niche between aerial photography and imagery from unmanned satellite scanners and complements these two familiar formats with additional information. The ability of the trained astronaut to rapidly identify and photograph interesting phenomena on the Earth makes the Shuttle photographs unique. Near-real-time information exchange with the crew facilitates the recording of current events of geological, oceanographic, environmental, and meteorological importance. Near-vertical or low-oblique angle photographs can be digitized at high resolution and used as three-band (RGB) remote sensing images in the same way a scientist would use data from Landsat, SPOT, or Terra satellites (Webb et al. 2000). These digital images can be classified to determine land use, land cover, or change over time.

Land-use classification using a Space Shuttle photograph of the Thailand coast (Webb et al. 2000).

More information on astronaut photography

Scientific publications using astronaut photography

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About Human Spaceflight
Introduction
International Space Station
Space Shuttle
Astronaut Photography
References

Astronaut candidates participate in Earth Science training.