Deep Space Climate Observatory

DSCOVR began as a proposal in 1998 by then-Vice President Al Gore for the purpose of whole-Earth observation at the Sun-Earth Lagrange point, from Earth. Originally known as Triana, named after Rodrigo de Triana, the first of Columbus's crew to sight land in the Americas, the spacecraft's original purpose was to provide a near-continuous view of the entire Earth and make that live image available via the Internet. Gore hoped not only to advance science with these images, but also to raise awareness of the Earth itself, updating the influential Blue Marble photograph that was taken by Apollo 17. In addition to an imaging camera, a radiometer would take the first direct measurements of how much sunlight is reflected and emitted from the whole Earth (albedo). This data could constitute a barometer for the process of global warming. The scientific goals expanded to measure the amount of solar energy reaching Earth, cloud patterns, weather systems, monitor the health of Earth's vegetation, and track the amount of UV light reaching the surface through the ozone layer. In 1999, NASA's Inspector General reported that "the basic concept of the Triana mission was not peer reviewed", and "Triana's added science may not represent the best expenditure of NASA's limited science funding". Members of the U.S. Congress asked the National Academy of Sciences whether the project was worthwhile. The resulting report, released March 2000, stated that the mission was "strong and scientifically vital". The Bush administration put the project on hold shortly after George W. Bush's inauguration in January 2001. NASA renamed the spacecraft Deep Space Climate Observatory (DSCOVR) in 2003 in an attempt to regain support for the project, In November 2008, funded by National Oceanic and Atmospheric Administration (NOAA) and the U.S. Air Force, the spacecraft was removed from storage and underwent testing to determine its viability for launch. After the Obama administration took presidency in 2009, that year's budget included US$9 million marked for refurbishment and readiness of the spacecraft, resulting in NASA refurbishing the EPIC instrument and recalibrating the NISTAR instrument. Al Gore used part of his book Our Choice (2009) as an attempt to revive debate on the DSCOVR payload. The book mentions legislative efforts by senators Barbara Mikulski and Bill Nelson to get the spacecraft launched. In February 2011, the Obama administration attempted to secure funding to re-purpose the DSCOVR spacecraft as a solar observatory to replace the aging Advanced Composition Explorer (ACE) spacecraft, and requested US$47.3 million in the 2012 fiscal budget toward this purpose. In September 2013, NASA cleared DSCOVR to proceed to the implementation phase targeting an early 2015 launch, which ultimately took place on 11 February 2015. == Spacecraft ==

DSCOVR is built on the SMEX-Lite spacecraft bus and has a launch mass of approximately . The main science instrument sets are the Sun-observing Plasma Magnetometer (PlasMag) and the Earth-observing NIST Advanced Radiometer (NISTAR) and Earth Polychromatic Imaging Camera (EPIC). DSCOVR has two deployable solar arrays, a propulsion module, boom, and antenna. The propulsion module had 145 kg of hydrazine propellant at launch. From its vantage point, DSCOVR monitors variable solar wind conditions, provides early warning of approaching coronal mass ejections and observes phenomena on Earth, including changes in ozone, aerosols, dust and volcanic ash, cloud height, vegetation cover and climate. At its Sun-Earth location it has a continuous view of the Sun and of the sunlit side of the Earth. After the spacecraft arrived on-site and entered its operational phase, NASA began releasing near-real-time images of Earth through the EPIC instrument's website. The spacecraft is in a looping halo orbit around the Sun–Earth Lagrange point L1 in a six-month period, with a spacecraft–Earth–Sun angle varying from 4° to 15°. Instruments PlasMag The Plasma-Magnetometer (PlasMag) measures solar wind for space weather predictions. It can provide early warning detection of solar activity that could cause damage to existing satellite systems and ground infrastructure. Because solar particles reach about an hour before Earth, PlasMag can provide a warning of 15 to 60 minutes before a coronal mass ejection (CME) arrives. It does this by measuring "the magnetic field and the velocity distribution functions of the electron, proton and alpha particles (helium nuclei) of solar wind". • Magnetometer measures magnetic field • Faraday cup measures positively charged particles • Electrostatic analyzer measures electrons EPIC away, centered on the Americas. The Earth Polychromatic Imaging Camera (EPIC) takes images of the sunlit side of Earth for various Earth science monitoring purposes in ten different channels from ultraviolet to near-infrared. Ozone and aerosol levels are monitored along with cloud dynamics, properties of the land, and vegetation. EPIC has an aperture diameter of , a focal ratio of 9.38, a field of view of 0.61°, and an angular sampling resolution of 1.07 arcseconds. Earth's apparent diameter varies from 0.45° to 0.53° full width. Exposure time for each of the 10 narrowband channels (317, 325, 340, 388, 443, 552, 680, 688, 764, and 779 nm) is about 40 ms. The camera produces 2048 × 2048 pixel images, but to increase the number of downloadable images to ten per hour the resolution is averaged to 1024 × 1024 on board. The final resolution is . Using NISTAR data, scientists can help determine the impact that humanity is having on the atmosphere of Earth and make the necessary changes to help balance the radiation budget. The radiometer measures in four channels: • For total radiation in ultraviolet, visible and infrared in the range 0.2–100 μm • For reflected solar radiation in the ultraviolet, visible and near-infrared in the range 0.2–4 μm • For reflected solar radiation in infrared in the range 0.7–4 μm • For calibration purposes in the range 0.3–1 μm == Launch ==

The DSCOVR launch was conducted by launch provider SpaceX using their Falcon 9 v1.1 rocket. The launch of DSCOVR took place on 11 February 2015, following two scrubbed launches. It took DSCOVR 110 days from when it left Cape Canaveral Air Force Station (CCAFS), Florida, to reach its target destination away from Earth orbiting the Sun-Earth L1 Lagrange point. Launch attempt history == Operation ==

On 6 July 2015, DSCOVR returned its first publicly released view of the entire earthlight side of Earth from away, taken by the EPIC instrument. EPIC provides a daily series of Earth images, enabling the first-time study of daily variations over the entire globe. The images, available 12 to 36 hours after they are made, have been posted to a dedicated web page since September 2015. On 16–17 July 2015, DSCOVR took a series of images showing the Moon during a transit of Earth. The images were taken between 19:50 and 00:45 UTC. The animation was composed of monochrome images taken in different color filters at 30-second intervals for each frame, resulting in a slight color fringing for the Moon in each finished frame. Due to its position at Sun–Earth L1, DSCOVR will always see the Moon illuminated and will always see its far side when it passes in front of Earth. On 19 October 2015, NASA opened a new website to host near-live "Blue Marble" images taken by EPIC of Earth. Twelve images are released each day, every two hours, showcasing Earth as it rotates on its axis. The resolution of the images ranges from , and the short exposure times renders points of starlight invisible. Operators programmed a software patch that allows DSCOVR to operate without a laser gyroscope, using only the star tracker for angular rate information. DSCOVR came out of the safe hold on 2 March 2020, and resumed normal operations. On 16 July 2025, DSCOVR suffered a software bus anomaly, which put it offline without an estimated date for recovery. On 12 October 2025, the amateur-operated Dwingeloo Radio Observatory received signals again., after which AMSAT-DL successfully downloaded EPIC images on 23 October 2025. == Picture Sequences ==