Deep Space Climate Observatory (DSCOVR; formerly known as Triana, unofficially known as GoreSat
) is a
National Oceanic and Atmospheric Administration
The National Oceanic and Atmospheric Administration (abbreviated as NOAA ) is an United States scientific and regulatory agency within the United States Department of Commerce that forecasts weather, monitors oceanic and atmospheric conditio ...
(NOAA)
space weather
Space weather is a branch of space physics and aeronomy, or heliophysics, concerned with the time varying conditions within the Solar System, including the solar wind, emphasizing the space surrounding the Earth, including conditions in the ...
,
space climate, and
Earth observation satellite. It was launched by
SpaceX on a
Falcon 9 v1.1
Falcon 9 v1.1 was the second version of SpaceX's Falcon 9 orbital launch vehicle. The rocket was developed in 2011–2013, made its maiden launch in September 2013, and its final flight in January 2016. The Falcon 9 rocket was fully designed ...
launch vehicle
A launch vehicle or carrier rocket is a rocket designed to carry a payload ( spacecraft or satellites) from the Earth's surface to outer space. Most launch vehicles operate from a launch pads, supported by a launch control center and ...
on 11 February 2015, from
Cape Canaveral. This is NOAA's first operational deep space satellite and became its primary system of warning
Earth
Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...
in the event of
solar magnetic storms.
[ ]
DSCOVR was originally proposed as an Earth observation spacecraft positioned at the
Sun-Earth Lagrange point, providing live video of the sunlit side of the planet through the Internet as well as scientific instruments to study climate change. Political changes in the
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...
resulted in the mission's cancellation, and in 2001 the spacecraft was placed into storage.
Proponents of the mission continued to push for its reinstatement, and a change in presidential administration in 2009 resulted in DSCOVR being taken out of storage and refurbished, and its mission was refocused to solar observation and early warning of
coronal mass ejection
A coronal mass ejection (CME) is a significant release of plasma and accompanying magnetic field from the Sun's corona into the heliosphere. CMEs are often associated with solar flares and other forms of solar activity, but a broadly accept ...
s while still providing Earth observation and climate monitoring. It launched aboard a
SpaceX Falcon 9
Falcon 9 is a partially reusable medium lift launch vehicle that can carry cargo and crew into Earth orbit, produced by American aerospace company SpaceX.
The rocket has two stages. The first (booster) stage carries the second stage and pay ...
launch vehicle on 11 February 2015, and reached on 8 June 2015.
NOAA operates DSCOVR from it
Satellite and Product Operations Facilityin
Suitland, Maryland. The acquired space data that allows for accurate weather forecasts are carried out in the
Space Weather Prediction Center
The Space Weather Prediction Center (SWPC), named the Space Environment Center (SEC) until 2007, is a laboratory and service center of the US National Weather Service (NWS), part of the National Oceanic and Atmospheric Administration (NOAA), loc ...
in
Boulder, Colorado. Archival records are held by the
National Centers for Environmental Information, and processing of Earth sensor data is carried out by
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the US federal government responsible for the civil List of government space agencies, space program ...
.
History
DSCOVR began as a proposal in 1998 by then-
Vice President
A vice president, also director in British English, is an officer in government or business who is below the president (chief executive officer) in rank. It can also refer to executive vice presidents, signifying that the vice president is on ...
Al Gore
Albert Arnold Gore Jr. (born March 31, 1948) is an American politician, businessman, and environmentalist who served as the 45th vice president of the United States from 1993 to 2001 under President Bill Clinton. Gore was the Democratic no ...
for the purpose of whole-Earth observation at the Sun-Earth
Lagrange point, from Earth.
Originally known as Triana, named after
Rodrigo de Triana
Rodrigo de Triana (born 1469 in Lepe, Huelva, Spain) was a Spanish sailor, believed to be the first European from the Age of Exploration to have seen the Americas. Born as Juan Rodríguez Bermejo, Triana was the son of hidalgo and potter Vicen ...
, the first of
Columbus's crew to sight land in the
Americas
The Americas, which are sometimes collectively called America, are a landmass comprising the totality of North and South America. The Americas make up most of the land in Earth's Western Hemisphere and comprise the New World.
Along with th ...
, 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
Albedo (; ) is the measure of the diffuse reflection of solar radiation out of the total solar radiation and measured on a scale from 0, corresponding to a black body that absorbs all incident radiation, to 1, corresponding to a body that refl ...
). This data could constitute a barometer for the process of
global warming
In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...
. 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
The United States Congress is the legislature of the federal government of the United States. It is bicameral, composed of a lower body, the House of Representatives, and an upper body, the Senate. It meets in the U.S. Capitol in Washin ...
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.
Triana was removed from its original launch opportunity on
STS-107
STS-107 was the 113th flight of the Space Shuttle program, and the 28th and final flight of Space Shuttle ''Columbia''. The mission launched from Kennedy Space Center in Florida on January 16, 2003, and during its 15 days, 22 hours, 20 minutes ...
(the
ill-fated ''Columbia'' mission in 2003).
The US$150 million
spacecraft was placed into
nitrogen blanketed storage at
Goddard Space Flight Center in November 2001 and remained there for the duration of the Bush administration.
NASA renamed the spacecraft Deep Space Climate Observatory (DSCOVR) in 2003 in an attempt to regain support for the project,
but the mission was formally terminated by NASA in 2005.
In November 2008, funded by
National Oceanic and Atmospheric Administration
The National Oceanic and Atmospheric Administration (abbreviated as NOAA ) is an United States scientific and regulatory agency within the United States Department of Commerce that forecasts weather, monitors oceanic and atmospheric conditio ...
(NOAA) and the
U.S. Air Force
The United States Air Force (USAF) is the air service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part of the United States Army Sign ...
, 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
Albert Arnold Gore Jr. (born March 31, 1948) is an American politician, businessman, and environmentalist who served as the 45th vice president of the United States from 1993 to 2001 under President Bill Clinton. Gore was the Democratic no ...
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
Barbara Ann Mikulski ( ; born July 20, 1936) is an American politician and social worker who served as a United States senator from Maryland from 1987 to 2017. A member of the Democratic Party, she also served in the United States House of Repr ...
and
Bill Nelson
Clarence William Nelson II (born September 29, 1942) is an American politician and attorney serving as the administrator of the National Aeronautics and Space Administration (NASA). Nelson previously served as a United States Senator from Flo ...
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
Advanced Composition Explorer (ACE or Explorer 71) is a NASA Explorer program satellite and space exploration mission to study matter comprising energetic particles from the solar wind, the interplanetary medium, and other sources.
Real-tim ...
(ACE) spacecraft, and requested US$47.3 million in the 2012 fiscal budget toward this purpose.
Part of this funding was to allow the
Naval Research Laboratory (NRL) to construct a coronal mass ejection imager for the spacecraft, but the time required would have delayed DSCOVR's launch and it was ultimately not included.
NOAA allocated US$2 million in its 2011 budget to initiate the refurbishment effort, and increased funding to US$29.8 million in 2012.
In 2012, the Air Force allocated US$134.5 million to procure a launch vehicle and fund launch operations, both of which were awarded to
SpaceX for their
Falcon 9
Falcon 9 is a partially reusable medium lift launch vehicle that can carry cargo and crew into Earth orbit, produced by American aerospace company SpaceX.
The rocket has two stages. The first (booster) stage carries the second stage and pay ...
rocket.
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.
NASA's
Goddard Space Flight Center is providing management and systems engineering to the mission.
In the 2017 documentary, ''
An Inconvenient Sequel: Truth to Power'', Al Gore speaks of the history of the DSCOVR spacecraft and its relation to climate change.
Spacecraft
DSCOVR is built on the
SMEX-Lite spacecraft
bus
A bus (contracted from omnibus, with variants multibus, motorbus, autobus, etc.) is a road vehicle that carries significantly more passengers than an average car or van. It is most commonly used in public transport, but is also in use for cha ...
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.
[ ]
From its vantage point, DSCOVR monitors variable
solar wind
The solar wind is a stream of charged particles released from the upper atmosphere of the Sun, called the corona. This plasma mostly consists of electrons, protons and alpha particles with kinetic energy between . The composition of the sol ...
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.
DSCOVR takes full-Earth pictures about every two hours and is able to process them faster than other
Earth observation satellites.
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
The solar wind is a stream of charged particles released from the upper atmosphere of the Sun, called the corona. This plasma mostly consists of electrons, protons and alpha particles with kinetic energy between . The composition of the sol ...
for
space weather
Space weather is a branch of space physics and aeronomy, or heliophysics, concerned with the time varying conditions within the Solar System, including the solar wind, emphasizing the space surrounding the Earth, including conditions in the ...
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
A coronal mass ejection (CME) is a significant release of plasma and accompanying magnetic field from the Sun's corona into the heliosphere. CMEs are often associated with solar flares and other forms of solar activity, but a broadly accept ...
(CME) arrives. It does this by measuring "the magnetic field and the velocity distribution functions of the electron, proton and alpha particles (
helium
Helium (from el, ἥλιος, helios, lit=sun) is a chemical element with the symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic table. ...
nuclei) of solar wind".
It has three instruments:
[ ]
* Magnetometer measures
magnetic field
*
Faraday cup
A Faraday cup is a metal (conductive) cup designed to catch charged particles in vacuum. The resulting current can be measured and used to determine the number of ions or electrons hitting the cup. The Faraday cup was named after Michael Fara ...
measures positively
charged particle
In physics, a charged particle is a particle with an electric charge. It may be an ion, such as a molecule or atom with a surplus or deficit of electrons relative to protons. It can also be an electron or a proton, or another elementary pa ...
s
* Electrostatic analyzer measures
electron
The electron ( or ) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first generation of the lepton particle family,
and are generally thought to be elementary particles because they have no ...
s
EPIC
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
Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiation ...
to
near-infrared
Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of Light, visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from ...
.
Ozone
Ozone (), or trioxygen, is an inorganic molecule with the chemical formula . It is a pale blue gas with a distinctively pungent smell. It is an allotrope of oxygen that is much less stable than the diatomic allotrope , breaking down in the lo ...
and
aerosol levels are monitored along with cloud dynamics, properties of the land, and
vegetation
Vegetation is an assemblage of plant species and the ground cover they provide. It is a general term, without specific reference to particular taxa, life forms, structure, spatial extent, or any other specific botanical or geographic characte ...
.
[ ]
EPIC has an aperture diameter of , a
focal ratio
In optics, the f-number of an optical system such as a camera lens is the ratio of the system's focal length to the diameter of the entrance pupil ("clear aperture").Smith, Warren ''Modern Optical Engineering'', 4th Ed., 2007 McGraw-Hill Pro ...
of 9.38, a
field of view
The field of view (FoV) is the extent of the observable world that is seen at any given moment. In the case of optical instruments or sensors it is a solid angle through which a detector is sensitive to electromagnetic radiation.
Human ...
of 0.61°, and an angular sampling resolution of 1.07
arcseconds. Earth's
apparent diameter
The angular diameter, angular size, apparent diameter, or apparent size is an angular distance describing how large a sphere or circle appears from a given point of view. In the vision sciences, it is called the visual angle, and in optics, it is ...
varies from 0.45° to 0.53° full width.
Exposure time
In photography, shutter speed or exposure time is the length of time that the film or digital sensor inside the camera is exposed to light (that is, when the camera's shutter is open) when taking a photograph.
The amount of light that re ...
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 .
[
]
NISTAR
The National Institute of Standards and Technology Advanced Radiometer (NISTAR) was designed and built between 1999 and 2001 by NIST in Gaithersburg, MD and Ball Aerospace & Technologies in Boulder, Colorado. NISTAR measures irradiance of the sunlit face of the Earth. This means that NISTAR measures if the atmosphere of Earth
The atmosphere of Earth is the layer of gases, known collectively as air, retained by Earth's gravity that surrounds the planet and forms its planetary atmosphere. The atmosphere of Earth protects life on Earth by creating pressure allowing fo ...
is taking in more or less solar energy than it is radiating back towards space. This data is to be used to study changes in Earth's radiation budget caused by natural and human activities.[ ]
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
Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiation ...
, visible and infrared
Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...
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
Falcon 9 v1.1 was the second version of SpaceX's Falcon 9 orbital launch vehicle. The rocket was developed in 2011–2013, made its maiden launch in September 2013, and its final flight in January 2016. The Falcon 9 rocket was fully designed ...
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
Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...
, to reach its target destination away from Earth at the Sun-Earth L1 Lagrange point.[ ]
Launch attempt history
Post-launch flight test
SpaceX planned to conduct a test flight where they would attempt to bring the first stage back through the atmosphere and land the expended first stage on a floating landing platform.
Relative to earlier tests, the first-stage return on DSCOVR was much more challenging, especially in atmospheric reentry due to the deep-space nature of the Earth–Sun L1 launch trajectory for DSCOVR. This would only be the second time that SpaceX ever tried to recover the first stage of the Falcon 9 launch vehicle. SpaceX expected deceleration-force loads to be twice as high and rocket heating to quadruple over the reentry conditions on Falcon 9 Flight 14. Before the launch, the drone ship was in ocean surface conditions that made the barge landing infeasible. Therefore, the landing platform attempt was called off, and the first stage made an over-water soft landing instead. This continued the collection of returnable first-stage test data on all the earlier phases of the flight test and added data on stage survival following a high-speed, high-load atmospheric entry.
2nd stage disposal
The second stage of the Falcon 9 launch vehicle, after releasing DSCOVR and supposedly surpassing L1, has probably been perturbed into a heliocentric orbit over time. In 2022 it was originally misidentified as a different piece of space debris and thought to have been on a collision course with the moon, but there's now evidence that the impacting object might actually be part of the Chang'e 5-T1 mission. Independent spectral analysis from the University of Arizona supports the Chinese origin of the object.
Operation
On 6 July 2015, DSCOVR returned its first publicly released view of the entire sunlit 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.
DSCOVR was placed in operation at the L1 Lagrange point to monitor the Sun
The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...
, because the constant stream of particles from the Sun (the solar wind
The solar wind is a stream of charged particles released from the upper atmosphere of the Sun, called the corona. This plasma mostly consists of electrons, protons and alpha particles with kinetic energy between . The composition of the sol ...
) reaches L1 about 60 minutes before reaching Earth. DSCOVR will usually be able to provide a 15 to 60 minutes warning before a surge of particles and magnetic field from a coronal mass ejection
A coronal mass ejection (CME) is a significant release of plasma and accompanying magnetic field from the Sun's corona into the heliosphere. CMEs are often associated with solar flares and other forms of solar activity, but a broadly accept ...
(CME) reaches Earth and creates a geomagnetic storm
A geomagnetic storm, also known as a magnetic storm, is a temporary disturbance of the Earth's magnetosphere caused by a solar wind shock wave and/or cloud of magnetic field that interacts with the Earth's magnetic field.
The disturbance that d ...
. DSCOVR data will also be used to improve predictions of the impact locations of a geomagnetic storm to be able to take preventative action. Electronic technologies such as satellites in geosynchronous orbit are at risk of unplanned disruptions without warnings from DSCOVR and other monitoring satellites at L1.[ ]
On 16–17 July 2015, DSCOVR took a series of images showing the Moon
The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...
during a transit of Earth. The images were taken between 19:50 and 00:45 UTC. The animation was composed of monochrome
A monochrome or monochromatic image, object or palette is composed of one color (or values of one color). Images using only shades of grey are called grayscale (typically digital) or black-and-white (typically analog). In physics, monochrom ...
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
Illuminated may refer to:
* "Illuminated" (song), by Hurts
* Illuminated Film Company, a British animation house
* ''Illuminated'', alternative title of Black Sheep (Nat & Alex Wolff album)
* Illuminated manuscript
See also
* Illuminate (disambi ...
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 time
In photography, shutter speed or exposure time is the length of time that the film or digital sensor inside the camera is exposed to light (that is, when the camera's shutter is open) when taking a photograph.
The amount of light that re ...
s renders points of starlight invisible.
On 27 June 2019, DSCOVR was put into safe mode due to an anomaly with the laser gyroscope of the Miniature Inertial Measurement Unit (MIMU), part of the spacecraft's attitude control
Attitude control is the process of controlling the orientation of an aerospace vehicle with respect to an inertial frame of reference or another entity such as the celestial sphere, certain fields, and nearby objects, etc.
Controlling vehicle ...
system. 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.
Animations
See also
* Clouds and the Earth's Radiant Energy System
Clouds and the Earth's Radiant Energy System (CERES) is NASA climatological experiment from Earth orbit. The CERES are scientific satellite instruments, part of the NASA's Earth Observing System (EOS), designed to measure both solar-reflected a ...
* STEREO
* Visual Monitoring Camera
* List of Falcon 9 and Falcon Heavy launches
References
External links
DSCOVR website
at NOAA.gov
DSCOVR
at eoPortal.org
EPIC global images
at NASA.gov
Further reading
*
*
*
** Rebuttal:
*
*
{{authority control
National Oceanic and Atmospheric Administration
Earth observation satellites of the United States
SpaceX payloads contracted by NASA
Space probes launched in 2015
Spacecraft using halo orbits
Spacecraft using Lissajous orbits
Earth imaging satellites
Geospace monitoring satellites
Artificial satellites at Earth-Sun Lagrange points