The Deep Space Climate Observatory (DSCOVR), a mission lead by the National Oceanic and Atmospheric Administration (NOAA) in partnership with NASA and the U.S. Air Force, will collect space weather measurements to enable space weather forecasting by NOAA. The satellite is planned for launch in January 2015 from Cape Canaveral Air Force Station's Space Launch Complex in Florida.
In addition to the space weather instruments, NASA is providing two Earth-observing instruments on the spacecraft, the Earth Polychromatic Imaging Camera (EPIC) and the National Institute of Standards and Technology Advanced Radiometer (NISTAR).
DSCOVR (formerly known as Triana) was originally conceived in the late 1990s as a NASA Earth science mission that would provide a near continuous view of Earth and measure Earth's albedo. Triana was canceled and the satellite went into storage in 2001.
NOAA funded NASA to remove DSCOVR from storage and test it in 2008. The same year, the Committee on Space Environmental Sensor Mitigation Options (an interagency assessment requested by the White House Office of Science and Technology Policy) determined that DSCOVR was the optimal solution for meeting NOAA and U.S. Air Force space weather requirements.
NOAA is responsible for the DSCOVR mission, providing program management, spacecraft operation and distribution of all mission data. NOAA funded NASA to refurbish the spacecraft, recalibrate the space weather sensors, prepare the spacecraft for launch; develop the ground systems and operations; and provide technical management of the space segment. DSCOVR will succeed NASA's Advanced Composition Explorer's (ACE) role in supporting solar wind alerts and warnings from NOAA.
In 2012, NASA brought the spacecraft out of storage at NASA's Goddard Space Flight Center in Greenbelt, Maryland, where the spacecraft was originally built. NASA inspected the instruments, tested the mechanisms, provided new electrical components and conducted environmental tests of the observatory.
In addition, NASA funded the refurbishment and recalibration of the two Earth science instruments and is supporting the analysis of their data. The U.S. Air Force will provide the SpaceX Falcon 9 launch vehicle through their launch services contract with SpaceX.
NASA Earth Science Instruments
DSCOVR will make unique space measurements from the first sun-Earth Lagrange point (L1). The L1 point is on the direct line between Earth and the sun located 1.5 million kilometers (930,000 miles) sunward from Earth, and is a neutral gravity point between Earth and the sun. The spacecraft will be orbiting this point in a six-month orbit with a spacecraft-Earth-sun angle varying between 4 and 15 degrees.
This L1 vantage point offers a continuous view of the entire sunlit half of Earth in a "snapshot," as opposed to other Earth observing satellites situated closer to Earth that capture an image strip that is later "stitched" together.
The NASA Earth Polychromatic Imaging Camera (EPIC) instrument provides spectral images of the entire sunlit face of Earth, as viewed from an orbit around L1. EPIC is able to view the entire sunlit Earth from sunrise to sunset.
EPIC's observations will provide a unique angular perspective, and will be used in science applications to measure ozone and aerosol amounts, cloud height, vegetation properties and ultraviolet reflectivity of Earth. The data from EPIC will be used by NASA for a number of Earth science developments including dust and volcanic ash maps of the entire Earth.
EPIC makes images of the sunlit face of the Earth in 10 narrowband spectral channels. As part of EPIC data processing, a full disk true color Earth image will be produced about every two hours. This information will be publicly available through NASA Langley Research Center in Hampton, Virginia, approximately 24 hours after the images are acquired.
The National Institute of Standards and Technology Advanced Radiometer (NISTAR) is the other DSCOVR NASA instrument, a cavity radiometer designed to measure the reflected and emitted energy (in the 0.2 to 100 micron range) from the entire sunlit face of Earth. This measurement is intended to improve understanding of the effects of changes in Earth's radiation budget caused by human activities and natural phenomena.
The information from NISTAR can be used for climate science applications. NISTAR will measure the amount of reflected sunlight and the thermal radiation of Earth in the direction towards the sun. These quantities are key ingredients of current climate models.
The NASA-Sponsored Earth Science Research
NASA's Science Mission Directorate selected the following proposals for the development of algorithms for the Earth-observing EPIC and NISTAR instruments on DSCOVR.
Accurate Ozone Product from EPICResearch Lead Richard McPeters, NASA Goddard Space Flight Center, will research methods to accurately capture short-term changes in the distribution of tropospheric ozone driven by geochemical and geophysical processes.
Volcanic Sulfur Dioxide and Ash Products from EPICResearch Lead Nickolay Krotkov, NASA Goddard Space Flight Center, will implement algorithms to enable sulfur dioxide and ash index products from EPIC ultraviolet observations.
Hourly Global Aerosol Index and Aerosol Particle Properties Using EPICEPIC Research Lead Omar Torres, NASA Goddard Space Flight Center, will develop absorbing aerosol index and above-cloud-aerosol optical depth products.
Atmospheric Correction of EPIC MeasurementsResearch Lead Alexei Lyapustin, NASA Goddard Space Flight Center, will develop atmospheric correction algorithm to provide spectral surface reflectance. As a byproduct, he will also provide internal cloud mask and aerosol optical thickness.
Earth System Data Records of Global Vegetation Index, Fraction of Absorbed PAR, Leaf Area and Its Sunlit FractionResearch Lead Yuri Knyazikhin, Boston University, will provide global data records of normalized difference vegetation index, fraction of photosynthetically active radiation absorbed by green leaves, leaf area and its sunlit fraction.
EPIC Cloud AlgorithmsResearch Lead Yuekui Yang, Universities Space Research Association, will develop a suite of algorithms for generating the operational EPIC cloud mask, cloud height and cloud optical thickness products.
Global Total Ozone and Volcanic Sulfur Dioxide Products from EPICResearch Lead Kai Yang, University of Maryland at College Park, will produce total ozone and sulfur dioxide vertical columns, ultraviolet reflectivity and ultraviolet aerosol index products from EPIC ultraviolet measurements.
Enhancements and Maintenance of EPIC Level 1 CalibrationResearch Lead Alexander Cede, SciGlob Instruments & Services, LLC, will develop products to improve the pre-launch calibration and stray light correction of EPIC based on proper analysis of in-flight data in combination with re-analysis of pre-launch data.
Determining the Daytime Global Radiation Budget from DSCOVRResearch Lead Patrick Minnis, NASA Langley Research Center, will develop a system that provides a global daytime Earth's radiation budget with accuracy better than 1.5 percent using both EPIC and NISTAR measurements.