LDCM Prepares for Launch – Continuing the Landsat legacy

NASA hosted a press conference last Thursday to highlight final preparations as LDCM – the Landsat Data Continuity Mission – prepares for launch on Feb 11, 2013.

LDCMWith the countdown to this momentous launch drawing near – now less than a month away – the excitement amongst the panel members at the press conference was clearly evident. Many eyes from around the world will be expectantly watching Vandenberg Air Force Base in California next month as LDCM lifts-off aboard an Atlas 5 rocket.

LDCM, which will officially be renamed Landsat 8 once in orbit, is important as the next satellite in the long-lived, and incredibly successful, Landsat program. With its new capabilities and improved instrument design, LDCM was described by panelists at the recent briefing as the “best Landsat ever”, delivering both “more data per day” and “higher quality data” than any previous Landsat.

Successful launch of LDCM becomes particularly crucial in light of recent announcements that Landsat 5 will soon be decommissioned and considering ongoing concerns related to the operational limitations of Landsat 7 [note that Landsat 6 failed to reach orbit during its 1993 launch, and thus never made it into operation]. While numerous other satellites provide their own capabilities for Earth observation, the unprecedented 40-year continuity of the Landsat program enables analysis of long-term trends and unique capabilities for the assessment and monitoring of our changing planet. LDCM thus represents more than just a new satellite, but a critically important continuation of numerous global science applications.

LDCM contains two science instruments, the Operational Land Imager (OLI) and the Thermal Infrared Sensor (TIRS). The OLI instrument will measure a total of nine spectral bands: eight multispectral bands at 30m resolution in the visible, near-infrared, and shortwave infrared; and one panchromatic band at 15m resolution in the visible. Unlike previous Landsat missions, which used whiskbroom instruments, the OLI utilizes a pushbroom configuration, thereby enabling improved signal-to-noise performance, i.e., improved data quality. The TIRS instrument will measure two thermal bands at 100m resolution, subdividing the single thermal band previously measured by Landsat 4-7. With this overall design configuration, the OLI and TIRS instruments together maintain the legacy of previous Landsat instruments, while at the same time expanding to include additional capabilities.

LDCM is a joint program between NASA and USGS, with NASA handling instrument development, spacecraft design and launch, and USGS handling flight operations, and data processing, distribution and archiving. Importantly, as has been the policy since 2008, data from Landsat 8 will be offered free to all interested users.

The launch will be streamed live on NASA TV (http://www.nasa.gov/multimedia/nasatv/). Don’t miss this historic occasion.

For more information on LDCM: http://ldcm.nasa.gov/

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NASA Earth Science Today – A look at current satellites

Earth

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/