Nearly three million images taken of Earth from Japan's Advanced Spaceborne Thermal Emission and Reflection Radiometer instrument, ASTER, have been made available to the general public at no cost.

ASTER has been operating aboard NASA's Terra spacecraft since late 1999. The instrument captures images of Earth to map out and monitor the planet's changing surface. To date, ASTER's 16-year-plus database consists of more than 2.95 million individual scenes.

Among some of those amazing scenes captured are images of glacial advances and retreats, crop stress, thermal pollution, coral reef degradation, damage from an EF-5 tornado in Oklahoma, flooding aftermath in Pakistan, volcanic eruptions in Iceland and wildfires in California.

In the past, only topographic maps of Earth were available to the public for free. Any other ASTER data products required a fee to be paid to Japan's Ministry of Economy, Trade and Industry (METI).

Therefore, this new change will not only make it easier for researchers looking to study the Earth using a wide variety of topographical data, but will also allow citizen scientists and students to engage more easily with the science and data behind Earth's geography, surface temperatures, elevation and other features.

"We anticipate a dramatic increase in the number of users of our data, with new and exciting results to come," said Michael Abrams, ASTER science team leader at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif., home to ASTER's U.S. science team.

Created to make detailed maps of the planet's elevation, reflectance and land surface temperature, ASTER captures images in visible and thermal infrared wavelengths, with spatial resolutions ranging from about 50 to 300 feet.

What's more is ASTER's data covers 99 percent of the planet's entire landmass, with one single scene spanning an area that measures about 37-by-37 miles.

Data collected from ASTER is then processed using algorithms developed at the JPL and the National Institute of Advanced Industrial Science and Technology (AIST) in Japan. Images provided by the instrument give scientists a clearer picture of how the planet is changing.

In theory, the release of ASTER's data has implications for monitoring vulnerable wetlands, rates of thermal pollution, coral reef degradation and mapping surface temperatures of soils and geology, to name a few.

The images are available to download from NASA's Land Process Distributed Active Archive Center that is at the U.S. Geological Survey's Earth Resources Observation and Science Center.