Black and Blue All Over – The imagery behind NASA’s marbles

NASA is well known for its astronaut program, space exploration, rockets, satellites, remote sensing, and numerous other scientific endeavors, but are you familiar with their marbles? They now come in two flavors, a blue marble and a black marble, both depicting stunning visual displays of our planet.

The blue marble portrays a daytime view of our planet as viewed from space, and the recently released black marble reveals a novel nighttime view. Both are global composites of images collected from orbiting satellites, which have been seamlessly stitched together into cohesive representations of the entire surface of the planet.  The marbles are available for you to view and download through the NASA website, either as static individual images or as rotating animations.

Blue Marble: Next GenerationBlue Marble: The original “blue marble” was a photo acquired by astronauts onboard Apollo 17 as they departed Earth on their way to the moon, 40 years ago today, on December 7, 1972. The now iconic photo of Earth has since inspired a host of similar images, acquired from both astronauts and satellites alike, as well as motivation to generate integrated image composites of the entire planet. NASA released the first of these global composites in 2002. This version of the Blue Marble was created using imagery from the MODIS sensor onboard NASA’s Terra satellite. MODIS (Moderate Resolution Imaging Spectroradiometer) is a multispectral instrument collecting measurements in 36 spectral bands (visible to long-wave infrared). But only those bands in the visible portion of the spectrum were used for the Blue Marble in order to generate a true-color likeness of the planet. An updated version of this composite, the Blue Marble: Next Generation, was released in 2005. Although similar to the previous version, and also based on imagery from the MODIS sensor, this new version has no clouds and twice the level of detail (500m pixels versus 1km pixels).

Black MarbleBlack Marble: Most recently, on December 5, 2012, NASA released its first nighttime composite of the planet, appropriately named the Black Marble. Imagery for this version was obtained from the multispectral VIIRS instrument onboard the Suomi NPP (National Polar-orbiting Partnership) satellite, launched just over a year ago in 2011. VIIRS (Visible Infrared Imaging Radiometer Suite) measures 22 spectral bands in the visible to long-wave infrared, including a panchromatic day/night band. This day/night band is particularly capable of recording images in low-light conditions, and is the source of imagery utilized for generating the Black Marble composite.

As would be expected, the imagery used to create the marbles represents the foundation for many different scientific studies. While the science behind the marbles is indeed important, their visual beauty alone is inspiring and a meaningful reminder of the interconnected nature of our planet.

For more details on NASA’s Blue Marble: http://earthobservatory.nasa.gov/Features/BlueMarble/

For more details on NASA’s Black Marble: http://www.nasa.gov/mission_pages/NPP/news/earth-at-night.html

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NASA Earth Science Today – A look at current satellites

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Earth from far above (image courtesy NASA)

Presently orbiting the Earth are a complex international array of satellites, providing services for navigation, communication, astronomy, security, and weather. Amongst these are also satellites dedicated to monitoring the environment in which we live, including our atmosphere, land and oceans. A previous post examined NASA Earth observing satellites planned for launch in the coming years. Today we look at some of the many NASA satellites that are currently in orbit around our planet.

TERRA: The heft of this satellite may be surprising, close to the size of a small bus and weighing over 11,000-lbs at launch. With this size, however, come extensive capabilities. The Terra satellite, an international mission launched in 1999, contains five separate instruments: ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer), CERES (Clouds and the Earth’s Radiant Energy System), MISR (Multi-angle Imaging SpectroRadiometer), MODIS (Moderate Resolution Imaging Spectroradiometer), and MOPITT (Measurement of Pollution in the Troposphere). Together these instruments provide a unique capacity to observe Earth’s land, ocean, atmosphere, snow, and ice, helping address questions related to climate variability and change, atmospheric composition, weather, and the water, carbon and energy cycles.

AQUA: This is a companion satellite to Terra, which, along with a collection of other existing and planned satellites, is an integral part of the multi-satellite Earth Observing System (EOS). Aqua was launched in 2002, and carries a total of six instruments: AIRS (Atmospheric Infrared Sounder), AMSU-A (Advanced Microwave Sounding Unit), HSB (Humidity Sounder for Brazil), AMSR-E (Advanced Microwave Scanning Radiometer for EOS), MODIS (Moderate Resolution Imaging Spectroradiometer), and CERES (Clouds and the Earth’s Radiant Energy System). Aqua and Terra have different orbit characteristics; hence the presence of MODIS and CERES on both satellites allows the same type of imagery to be collected at different times of the day.

TRMM (Tropical Rainfall Measuring Mission): As would be expected from its name, the mission of this satellite is focused on measuring and understanding precipitation patterns in the tropics. The mission also provides information of tropical latent heating characteristics, which will help scientists better model the global energy budget. TRMM was launched 1997 and carries five instruments: PR (Precipitation Radar), TMI (TRMM Microwave Imager), VIRS (Visible and InfraRed Scanner), CERES (Clouds and the Earth’s Radiant Energy System), and LIS (Lightning Imaging Sensor).

CloudSat: Unlike some of the other satellites, CloudSat carries a single instrument, the CPR (Cloud Profiling Radar). This instrument builds on the strong legacy of radar expertise at NASA, following the success of other instruments such as SRTM, SIR-A, SIR-B, SIR-C, QuickScat and SeaWinds. The CPR instrument on CloudSat, launched in 2006, measures the vertical profiles of clouds, providing valuable information on cloud structure and composition. Such data is a critical component in the study of climate and weather dynamics around the planet.

AURA: The four instruments aboard the Aura satellite, launched in 2004, are designed to examine Earth’s atmosphere. Measurements are targeted at better understanding trends in air quality, atmospheric composition, ozone distribution, and the climate. The instruments on Aura include: HIRDLS (High Resolution Dynamics Limb Sounder), MLS (Microwave Limb Sounder), OMI (Ozone Monitoring Instrument), and TES (Tropospheric Emission Spectrometer).

As evident from the above descriptions, a common theme among many of the Earth observing satellites is the co-location of multiple instruments on a single satellite platform. This is not only more efficient in terms of engineering, launch and management, but also facilitates the acquisition of multiple images from different types of instruments at the same time and place in orbit. Another theme is placing the same type instrument on different satellites, allowing image collection to be performed with more frequency. At the same time there are some satellites containing just one instrument with very specific measurement objectives. Together these satellites provide a multifaceted look at our planet that can be used to address a myriad of important science and societal questions.

For information on NASA’s satellite program, visit: http://science.nasa.gov/earth-science/missions/

The Future of NASA Earth Science – Preview of upcoming satellite launches

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The “Blue Marble” (image courtesy NASA)

Since its establishment in 1958, NASA has become well known for its advances in space exploration, and closer to home, highly recognized for its long history of scientific research using Earth observing satellites. From the early days of the TIROS program, whose first satellite was launched in 1960, to the more recent Landsat program, which has spanned 40 years of operation from 1972 to present (…and still going), NASA has been a leader in using satellite observations to improve our understanding of Earth.

NASA is currently operating an unprecedented number of Earth observing satellites, with many more in the pipeline. Here’s a look at some of the instruments NASA plans on launching in the coming years:

LDCM: Landsat Data Continuity Mission. As mentioned, the Landsat program has been operating since 1972. This longevity has enabled an enormous volume of remote sensing research to be accomplished, primarily focused on land surfaces but also including applications in the shallow coastal zone. With the lifespans of all the previous Landsat instruments reaching their end, and a hardware failure on Landsat 7, NASA recognized the need to move forward with a replacement to this important family of instruments. The LDCM will contain two instruments, the Operational Land Imager, measuring nine bands in the visible to short wave infrared, eight multispectral and one panchromatic, and the Thermal Infrared Sensor, measuring two thermal bands. LDCM, a collaborative mission between NASA and USGS, is currently scheduled for launch in early 2013.

GPM: Global Precipitation Measurement. The GPM mission, an international partnership co-led by NASA and JAXA (Japan Aerospace and Exploration Agency), builds on the success of TRMM (Tropical Rainfall Measuring Mission) launched in 1997. Whereas TRMM was designed to measure rainfall in the tropical and sub-tropical regions, GPM will acquire global measurements of both rainfall and snow. The concept for the GPM mission centers on a Core Observatory satellite, which will contain the latest advanced instruments to serve as a reference for calibrating measurements from a host of other operational satellites. The GPM Core Observatory contains two instruments, the GMI (GPM Microwave Imager) and the DPR (Dual-Frequency Precipitation Radar). The GPM Core Observatory is scheduled for launch in 2014.

OCO-2: Orbiting Carbon Observatory. The OCO-2 mission is a replacement satellite for the original OCO instrument launched in 2009 that unfortunately failed to make orbit. OCO-2 will acquire precise global measurements of atmospheric carbon dioxide, providing scientists with an unprecedented ability to explore the spatial and temporal patterns of carbon dioxide levels in our planet’s atmosphere. Measurements will be obtained using a single instrument containing three separate spectrometers to measure three narrow bands in the near-infrared that are sensitive to the presence of atmospheric gases.  OCO-2 is scheduled for launch in 2014.

SMAP: Soil Moisture Active Passive. Understanding soil moisture plays an important role in weather and climate forecasting, as well as predicting droughts, floods, landslides and agricultural productivity. To address this need, the SMAP mission will deliver global measurements of both soil moisture and its freeze/thaw state. SMAP measurements will be made using two L-band instruments, a radiometer and a synthetic aperture radar. Utilizing the L-band frequency allows measurements to be acquired night or day, irrespective of cloud cover, and even through moderate vegetation. SMAP is scheduled for launch in late 2014.

As each new instrument passes through the requisite design review process, it moves closer to approval for launch. Listed above are just some of the instruments approaching this auspicious achievement. There are many more on the way, with even more in the early planning stages. As a result of this ongoing progress, our ability to assess and monitor the condition of our planet has never been greater, with bold plans to continue improving this capacity in the future.

For more on NASA’s history, visit: http://history.nasa.gov/

For information on NASA’s satellite program, visit: http://science.nasa.gov/earth-science/missions/