The Solar Dynamics Observatory (SDO) is a

NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...

mission which has been observing the

Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...

since 2010. Launched on 11 February 2010, the observatory is part of the Living With a Star (LWS) program. The goal of the LWS program is to develop the scientific understanding necessary to effectively address those aspects of the connected

–

Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...

system directly affecting life on Earth and its society. The goal of the SDO is to understand the influence of the Sun on the Earth and near-Earth space by studying the solar atmosphere on small scales of space and time and in many wavelengths simultaneously. SDO has been investigating how the Sun's magnetic field is generated and structured, how this stored magnetic energy is converted and released into the

heliosphere The heliosphere is the magnetosphere, astrosphere, and outermost atmospheric layer of the Sun. It takes the shape of a vast, tailed bubble-like region of space. In plasma physics terms, it is the cavity formed by the Sun in the surrounding ...

and geospace in the form of

solar wind The solar wind is a stream of charged particles released from the Sun's outermost atmospheric layer, the Stellar corona, corona. This Plasma (physics), plasma mostly consists of electrons, protons and alpha particles with kinetic energy betwee ...

, energetic particles, and variations in the

solar irradiance Solar irradiance is the power per unit area (surface power density) received from the Sun in the form of electromagnetic radiation in the wavelength range of the measuring instrument. Solar irradiance is measured in watts per square metre ( ...

General

The SDO spacecraft was developed at NASA's

Goddard Space Flight Center The Goddard Space Flight Center (GSFC) is a major NASA space research laboratory located approximately northeast of Washington, D.C., in Greenbelt, Maryland, United States. Established on May 1, 1959, as NASA's first space flight center, GSFC ...

Greenbelt, Maryland Greenbelt is a city in Prince George's County, Maryland, United States, and a suburb of Washington, D.C. At the 2020 United States census, 2020 census, the population was 24,921. Greenbelt is the first and the largest of the three experimental ...

, and launched on 11 February 2010, from Cape Canaveral Air Force Station ( CCAFS). The primary mission lasted five years and three months, with expendables expected to last at least ten years. Some consider SDO to be a follow-on mission to the Solar and Heliospheric Observatory (SOHO). SDO is a three-axis stabilized spacecraft, with two solar arrays, and two high-gain antennas, in an inclined

geosynchronous orbit A geosynchronous orbit (sometimes abbreviated GSO) is an Earth-centered orbit with an orbital period that matches Earth's rotation on its axis, 23 hours, 56 minutes, and 4 seconds (one sidereal day). The synchronization of rotation and orbital ...

around

. The spacecraft includes three instruments: * the Extreme Ultraviolet Variability Experiment (EVE) built in partnership with the

University of Colorado Boulder The University of Colorado Boulder (CU Boulder, CU, or Colorado) is a public research university in Boulder, Colorado, United States. Founded in 1876, five months before Colorado became a state, it is the flagship university of the University o ...

Laboratory for Atmospheric and Space Physics The Laboratory for Atmospheric and Space Physics (LASP) is a research organization at the University of Colorado Boulder. LASP is a research institute with over one hundred research scientists ranging in fields from solar influences, to Earth ...

(LASP), * the Helioseismic and Magnetic Imager (HMI) built in partnership with

Stanford University Leland Stanford Junior University, commonly referred to as Stanford University, is a Private university, private research university in Stanford, California, United States. It was founded in 1885 by railroad magnate Leland Stanford (the eighth ...

, and * the Atmospheric Imaging Assembly (AIA) built in partnership with the Lockheed Martin Solar and Astrophysics Laboratory (LMSAL). Data which are collected by the craft are made available as soon as possible after reception.

Extended mission

As of February 2020, SDO is expected to remain operational until 2030.

Instruments

Helioseismic and Magnetic Imager (HMI)

The Helioseismic and Magnetic Imager (HMI), led from

Stanford, California Stanford is a census-designated place (CDP) in the northwest corner of Santa Clara County, California, United States. It is the home of Stanford University, after which it was named. The CDP's population was 21,150 at the United States Census, ...

, studies solar variability and characterizes the Sun's interior and the various components of magnetic activity. HMI takes high-resolution measurements of the longitudinal and vector magnetic field by viewing the entirety of the Sun's disk, with emphasis on various concentrations of metals in the Sun; specifically it passes the light (the variety of usable frequencies of which are centered on the solar spectrum's 617.3-nm

Fraunhofer line The Fraunhofer lines are a set of spectral absorption lines. They are dark absorption lines, seen in the optical spectrum of the Sun, and are formed when atoms in the solar atmosphere absorb light being emitted by the solar photosphere. The ...

) through five filter instruments including a Lyot filter and two

Michelson interferometer The Michelson interferometer is a common configuration for optical interferometry and was invented by the American physicist Albert Abraham Michelson in 1887. Using a beam splitter, a light source is split into two arms. Each of those light be ...

s to rapidly and frequently create Doppler images and magnetograms. The full-disk focus and advanced magnetometers improve on the capabilities of

SOHO SoHo, short for "South of Houston Street, Houston Street", is a neighborhood in Lower Manhattan, New York City. Since the 1970s, the neighborhood has been the location of many artists' lofts and art galleries, art installations such as The Wall ...

's MDI instrument which could only focus within the line of sight with limited magnetic data. HMI produces data to determine the interior sources and mechanisms of solar variability and how the physical processes inside the Sun are related to surface magnetic field and activity. It also produces data to enable estimates of the coronal magnetic field for studies of variability in the extended solar atmosphere. HMI observations will enable establishing the relationships between the internal dynamics and magnetic activity in order to understand solar variability and its effects.

Extreme Ultraviolet Variability Experiment (EVE)

The Extreme Ultraviolet Variability Experiment (EVE) measures the

extreme ultraviolet Extreme ultraviolet radiation (EUV or XUV) or high-energy ultraviolet radiation is electromagnetic radiation in the part of the electromagnetic spectrum spanning wavelengths shorter than the hydrogen Lyman-alpha line from 121 nm down to ...

irradiance with improved

spectral resolution The spectral resolution of a spectrograph, or, more generally, of a frequency spectrum, is a measure of its ability to resolve features in the electromagnetic spectrum. It is usually denoted by \Delta\lambda, and is closely related to the resolvi ...

, temporal cadence, accuracy, and precision over preceding measurements made by

TIMED timed (time daemon) is an operating system program that maintains the system time in synchronization with time servers using the Time Synchronization Protocol (TSP) developed by Riccardo Gusella and Stefano Zatti. Gusella and Zatti had done e ...

SEE,

, and SORCE XPS. Some key requirements for EVE are to measure the solar EUV irradiance spectrum with 0.1 nm spectral resolution and with 20 sec cadence. These drive the EVE design to include grating spectrographs with array detectors so that all EUV wavelengths can be measured simultaneously. The instrument incorporates physics-based models in order to further scientific understanding of the relationship between solar EUV variations and magnetic variation changes in the Sun. The Sun's output of energetic extreme ultraviolet

photon A photon () is an elementary particle that is a quantum of the electromagnetic field, including electromagnetic radiation such as light and radio waves, and the force carrier for the electromagnetic force. Photons are massless particles that can ...

s is primarily what heats the

upper atmosphere Upper atmosphere is a collective term that refers to various layers of the atmosphere of the Earth above the troposphere and corresponding regions of the atmospheres of other planets, and includes: * The mesosphere, which on Earth lies between th ...

and creates the

ionosphere The ionosphere () is the ionized part of the upper atmosphere of Earth, from about to above sea level, a region that includes the thermosphere and parts of the mesosphere and exosphere. The ionosphere is ionized by solar radiation. It plays ...

. Solar EUV

radiation In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or a material medium. This includes: * ''electromagnetic radiation'' consisting of photons, such as radio waves, microwaves, infr ...

output undergoes constant changes, both moment to moment and over the Sun's 11-year

solar cycle The Solar cycle, also known as the solar magnetic activity cycle, sunspot cycle, or Schwabe cycle, is a periodic 11-year change in the Sun's activity measured in terms of Modern Maximum, variations in the number of observed sunspots on the Sun ...

, and these changes are important to understand because they have a significant impact on atmospheric heating, satellite drag, and

communication Communication is commonly defined as the transmission of information. Its precise definition is disputed and there are disagreements about whether Intention, unintentional or failed transmissions are included and whether communication not onl ...

s system degradation, including disruption of the

Global Positioning System The Global Positioning System (GPS) is a satellite-based hyperbolic navigation system owned by the United States Space Force and operated by Mission Delta 31. It is one of the global navigation satellite systems (GNSS) that provide ge ...

. The EVE instrument package was built by the

(LASP), with Dr. Tom Woods as principal investigator, and was delivered to NASA

on 7 September 2007. The instrument provides improvements of up to 70% in spectral resolution measurements in the wavelengths below 30 nm, and a 30% improvement in time cadence by taking measurements every 10 seconds over a 100%

duty cycle A duty cycle or power cycle is the fraction of one period in which a signal or system is active. Duty cycle is commonly expressed as a percentage or a ratio. A period is the time it takes for a signal to complete an on-and-off cycle. As a for ...

Atmospheric Imaging Assembly (AIA)

The Atmospheric Imaging Assembly (AIA), led from the Lockheed Martin Solar and Astrophysics Laboratory (LMSAL), provides continuous full-disk observations of the solar

chromosphere A chromosphere ("sphere of color", from the Ancient Greek words χρῶμα (''khrôma'') 'color' and σφαῖρα (''sphaîra'') 'sphere') is the second layer of a Stellar atmosphere, star's atmosphere, located above the photosphere and below t ...

and corona in seven

(EUV) channels, spanning a temperature range from approximately 20,000 Kelvin to in excess of 20 million Kelvin. The 12-second cadence of the image stream with 4096 by 4096 pixel images at 0.6 arcsec/pixel provides unprecedented views of the various phenomena that occur within the evolving solar outer atmosphere. The AIA science investigation is led by LMSAL, which also operates the instrument and – jointly with Stanford University – runs the Joint Science Operations Center from which all of the data are served to the worldwide scientific community, as well as the general public. LMSAL designed the overall instrumentation and led its development and integration. The four telescopes providing the individual light feeds for the instrument were designed and built at the

Smithsonian Astrophysical Observatory The Smithsonian Astrophysical Observatory (SAO) is a research institute of the Smithsonian Institution, concentrating on Astrophysics, astrophysical studies including Galactic astronomy, galactic and extragalactic astronomy, cosmology, Sun, solar ...

(SAO). Since beginning its operational phase on 1 May 2010, AIA has operated successfully with unprecedented EUV image quality. Photographs of the Sun in these various regions of the spectrum can be seen at NASA's SDO Data website. Images and movies of the Sun seen on any day of the mission, including within the last half-hour, can be found a
The Sun Today

Communications

SDO down-links science data ( K-band) from its two onboard

high-gain antenna A directional antenna or beam antenna is an antenna that radiates or receives greater radio wave power in specific directions. Directional antennas can radiate radio waves in beams, when greater concentration of radiation in a certain direction ...

s, and

telemetry Telemetry is the in situ collection of measurements or other data at remote points and their automatic transmission to receiving equipment (telecommunication) for monitoring. The word is derived from the Greek roots ''tele'', 'far off', an ...

(

S-band The S band is a designation by the Institute of Electrical and Electronics Engineers (IEEE) for a part of the microwave band of the electromagnetic spectrum covering frequencies from 2 to 4 gigahertz (GHz). Thus it crosses the convention ...

) from its two onboard

omnidirectional antenna In radio communication, an omnidirectional antenna is a class of antenna (electronics), antenna which radiates equal radio power in all directions perpendicular to an Cartesian coordinate system, axis (azimuthal directions), with power varying wi ...

s. The ground station consists of two dedicated (redundant) 18-meter radio antennas in

White Sands Missile Range White Sands Missile Range (WSMR) is a United States Army military testing area and firing range located in the US state of New Mexico. The range was originally established in 1941 as the Alamogordo Bombing and Gunnery Range, where the Trinity t ...

New Mexico New Mexico is a state in the Southwestern United States, Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also ...

, constructed specifically for SDO. Mission controllers operate the spacecraft remotely from the Mission Operations Center at

. The combined data rate is about 130 Mbit/s (150 Mbit/s with overhead, or 300 Msymbols/s with rate 1/2 convolutional encoding), and the craft generates approximately 1.5

Terabytes The byte is a unit of digital information that most commonly consists of eight bits. Historically, the byte was the number of bits used to encode a single character of text in a computer and for this reason it is the smallest addressable un ...

of data per day (equivalent to downloading around 500,000 songs).

Launch

Launch Services Program The NASA Launch Services Program (LSP) is responsible for procurement of launch services for NASA uncrewed missions and oversight of launch integration and launch preparation activity, providing added quality and mission assurance to meet program ...

Kennedy Space Center The John F. Kennedy Space Center (KSC, originally known as the NASA Launch Operations Center), located on Merritt Island, Florida, is one of the NASA, National Aeronautics and Space Administration's (NASA) ten NASA facilities#List of field c ...

managed the payload integration and launch. The SDO launched from

Cape Canaveral Space Launch Complex 41 Space Launch Complex 41 (SLC-41), sometimes referred to as "Slick Forty-one," is one of two launch sites at the Integrate-Transfer-Launch Complex in Cape Canaveral Space Force Station, Florida. Originally built as Launch Complex 41 (LC-41), it and ...

(SLC-41), utilizing an

Atlas V Atlas V is an expendable launch system and the fifth major version in the Atlas (rocket family), Atlas launch vehicle family. It was developed by Lockheed Martin and has been operated by United Launch Alliance (ULA) since 2006. Primarily used to ...

-401 rocket with a

RD-180 The RD-180 () is a rocket engine that was designed and built in Russia. It features a dual combustion chamber, dual-nozzle design and is fueled by a RP-1/ LOX mixture. The RD-180 is derived from the RD-170 line of rocket engines, which were use ...

powered Common Core Booster, which has been developed to meet the

Evolved Expendable Launch Vehicle National Security Space Launch (NSSL) is a program of the United States Space Force (USSF) intended to assure access to space for United States Department of Defense and other United States government payloads. The program is managed by the Assure ...

(EELV) program requirements. Sun dog phenomenon: Moments after launch, SDO's Atlas V rocket penetrated a

cirrus cloud Cirrus ( cloud classification symbol: Ci) is a genus of high cloud made of ice crystals. Cirrus clouds typically appear delicate and wispy with white strands. In the Earth's atmosphere, cirrus are usually formed when warm, dry air rises, causing ...

which created visible

shock wave In physics, a shock wave (also spelled shockwave), or shock, is a type of propagating disturbance that moves faster than the local speed of sound in the medium. Like an ordinary wave, a shock wave carries energy and can propagate through a me ...

s in the sky and destroyed the alignment of ice crystals that were forming a

sun dog A sun dog (or sundog) or mock sun, also called a parhelion (plural parhelia) in atmospheric science, is an atmospheric optical phenomenon that consists of a bright spot to one or both sides of the Sun. Two sun dogs often flank the Sun within ...

visible to onlookers. After launch, the spacecraft was deployed from the Atlas V into an

orbit In celestial mechanics, an orbit (also known as orbital revolution) is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an ...

around the

with an initial

perigee An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. The line of apsides (also called apse line, or major axis of the orbit) is the line connecting the two extreme values. Apsides perta ...

of about .

Transfer to final Orbit

Animation of Solar Dynamics Observatory trajectory

SDO then underwent a series of orbit-raising maneuvers over a few weeks which adjusted its orbit until the spacecraft reached its planned circular,

at an altitude of , at 102° West

longitude Longitude (, ) is a geographic coordinate that specifies the east- west position of a point on the surface of the Earth, or another celestial body. It is an angular measurement, usually expressed in degrees and denoted by the Greek lett ...

, inclined at 28.5°. This orbit was chosen to allow 24/7 communications to/from the fixed ground station, and to minimise

solar eclipse A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby obscuring the view of the Sun from a small part of Earth, totally or partially. Such an alignment occurs approximately every six months, during the eclipse season i ...

s to about an hour a day for only a few weeks a year.

Mission mascot - Camilla

Camilla Corona is a rubber chicken and is the mission

mascot A mascot is any human, animal, or object thought to bring luck, or anything used to represent a group with a common public identity, such as a school, sports team, university society, society, military unit, or brand, brand name. Mascots are als ...

for SDO. It is part of the

Education and public outreach Science outreach, also called education and public outreach (EPO or E/PO) or simply public outreach, is an umbrella term for a variety of activities by research institutes, University, universities, and institutions such as science museums, aimed ...

team and assists with various functions to help educate the public, mainly children, about the SDO mission, facts about the Sun and

Space weather Space weather is a branch of space physics and aeronomy, or heliophysics, concerned with the varying conditions within the Solar System and its heliosphere. This includes the effects of the solar wind, especially on the Earth's magnetosphere, ion ...

. Camilla also assists in cross-informing the public about other

missions and space related projects. Camilla Corona SDO uses

social media Social media are interactive technologies that facilitate the Content creation, creation, information exchange, sharing and news aggregator, aggregation of Content (media), content (such as ideas, interests, and other forms of expression) amongs ...

to interact with fans.

Image gallery

File:11742 SDO-Year 5 ProRes 1920x1080 2997.webm, SDO: Year 5 File:Camilla Corona SDO.jpg, Camilla Corona SDO File:Solar Dynamics Observatory.png, SDO 3-D schematic File:SDO spacecraft detailed.jpg, SDO Instruments File:SDO from above.jpg, SDO ready to be placed on Atlas rocket for launch. File:SDO Launch and Deployment.ogg, An animation showing the deployment of SDO. File:SDO first light.png, First light image from the SDO showing a prominence eruption. File:SDO's Ultra-high Definition View of 2012 Venus Transit (304 Angstrom Full Disc 02).jpg, An image of the

2012 transit of Venus The 2012 transit of Venus, when the planet Venus appeared as a small, dark spot passing across the face of the Sun, began at 22:09 UTC on 5 June 2012, and finished at 04:49 UTC on 6 June. Depending on the position of the observer, the exact ti ...

taken by SDO. File:Solar Dynamics Observatory - Argo view.ogg, This movie opens with a full-disk view of the Sun in visible wavelengths. Then the filters are applied to small pie-shaped wedges of the Sun. File:NASA's Solar Dynamics Observatory- Year 7 Ultra HD (4k).webm, SDO has now captured nearly seven years worth of ultra-high resolution solar footage. This time lapse shows that full run from two of SDO's instruments.

Stamps

In 2021, the United States Postal Service released a series of forever stamps using images of the Sun taken by the Solar Dynamics Observatory.

References

External links

Solar Dynamics Observatory (SDO) mission website

Where is the Solar Dynamics Observatory (SDO) right now?

HELAS

(Cometal 14 July 2011)
History of SDO patch
Facebook

( Flag of Hungary

)
Album
of images and videos by Seán Doran, based on SDO imagery, and a longer (24 min.) YouTube video
''Sun Dance''

SDO 5-year timelapse video of the Sun

SDO 10-year timelapse video of the Sun

Instruments

Extreme Ultraviolet Variability Experiment (EVE)
,

University of Colorado The University of Colorado (CU) is a system of public universities in Colorado. It consists of four institutions: the University of Colorado Boulder, the University of Colorado Colorado Springs, the University of Colorado Denver, and the U ...

ATMOSPHERIC IMAGING ASSEMBLY (AIA)

Lockheed Martin The Lockheed Martin Corporation is an American Arms industry, defense and aerospace manufacturer with worldwide interests. It was formed by the merger of Lockheed Corporation with Martin Marietta on March 15, 1995. It is headquartered in North ...

Helioseismic and Magnetic Imager (HMI)

Stanford Leland Stanford Junior University, commonly referred to as Stanford University, is a private research university in Stanford, California, United States. It was founded in 1885 by railroad magnate Leland Stanford (the eighth governor of and th ...

Joint Science Operations Center – Science Data Processing HMI – AIA
{{Authority control Space probes launched in 2010 NASA space probes Living With a Star Missions to the Sun Solar space observatories Solar telescopes Space weather Articles containing video clips Spacecraft launched by Atlas rockets

General

Extended mission

Instruments

Helioseismic and Magnetic Imager (HMI)

Extreme Ultraviolet Variability Experiment (EVE)

Atmospheric Imaging Assembly (AIA)

Communications

Launch

Transfer to final Orbit

Mission mascot - Camilla

Image gallery

Stamps

See also

References

External links

Instruments