Solar Dynamics Observatory
Solar Dynamics Observatory satellite
NamesSDO
Mission typeSolar research[1]
OperatorNASA GSFC[2]
COSPAR ID2010-005A
SATCAT no.36395
Websitehttp://sdo.gsfc.nasa.gov
Mission duration5 years (planned)
13 years, 11 months (elapsed)
Spacecraft properties
Spacecraft typeSolar Dynamics Observatory
ManufacturerGoddard Space Flight Center
Launch mass3,100 kg (6,800 lb)
Dry mass1,700 kg (3,700 lb)
Payload mass290 kg (640 lb)
Start of mission
Launch date11 February 2010, 15:23:00 UTC
RocketAtlas V 401
Launch siteCape Canaveral, SLC-41
ContractorUnited Launch Alliance
Orbital parameters
Reference systemGeocentric orbit[3]
RegimeGeosynchronous orbit
Longitude102° West

Solar Dynamics Observatory patch  

The Solar Dynamics Observatory (SDO) is a NASA mission which has been observing the Sun since 2010.[4] Launched on 11 February 2010, the observatory is part of the Living With a Star (LWS) program.[5]

The goal of the LWS program is to develop the scientific understanding necessary to effectively address those aspects of the connected Sun–Earth 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 and geospace in the form of solar wind, energetic particles, and variations in the solar irradiance.[6]

General

The SDO spacecraft was developed at NASA's Goddard Space Flight Center in Greenbelt, Maryland, 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.[7] Some consider SDO to be a follow-on mission to the Solar and Heliospheric Observatory (SOHO).[8]

SDO is a three-axis stabilized spacecraft, with two solar arrays, and two high-gain antennas, in an inclined geosynchronous orbit around Earth.

The spacecraft includes three instruments:

Data which is collected by the craft is made available as soon as possible, after it is received.[9]

Extended mission

As of February 2020, SDO is expected to remain operational until 2030.[10]

Instruments

Helioseismic and Magnetic Imager (HMI)

Comparison of HMI Continuum images immediately after an eclipse, and then after the sensor has re-warmed.

The Helioseismic and Magnetic Imager (HMI), led from Stanford University in Stanford, California, 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, with a range centered on the solar spectrum's 617.3-nm Fraunhofer line, passing the light through five filter instruments including a Lyot filter and two Michelson interferometers to rapidly and frequently create Doppler images and magnetograms. The full-disk focus and advanced magnetometers, improve on the capabilities of SOHO's MDI instrument which could only focus within the line of sight with limited magnetic data.[11][12]

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.[13]

Extreme Ultraviolet Variability Experiment (EVE)

The Extreme Ultraviolet Variability Experiment (EVE) measures the Sun's extreme ultraviolet irradiance with improved spectral resolution, "temporal cadence", accuracy, and precision over preceding measurements made by TIMED SEE, SOHO, and SORCE XPS. 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.[14]

The Sun's output of energetic extreme ultraviolet photons is primarily what heats the Earth's upper atmosphere and creates the ionosphere. Solar EUV radiation output undergoes constant changes, both moment to moment and over the Sun's 11-year solar cycle, and these changes are important to understand because they have a significant impact on atmospheric heating, satellite drag, and communications system degradation, including disruption of the Global Positioning System.[15]

The EVE instrument package was built by the University of Colorado Boulder's Laboratory for Atmospheric and Space Physics (LASP), with Dr. Tom Woods as principal investigator,[7] and was delivered to NASA Goddard Space Flight Center on 7 September 2007.[16] 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.[15]

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 and corona in seven extreme ultraviolet (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 (SAO).[17] Since beginning its operational phase on 1 May 2010, AIA has operated successfully with unprecedented EUV image quality.

AIA wavelength channelSource [18]Region of solar atmosphereCharacteristic
temperature
White light (450 nm)continuumPhotosphere5000 K
170 nmcontinuumTemperature minimum, photosphere5000 K
160 nmC IV + continuumTransition region and upper photosphere105 and 5000 K
33.5 nmFe XVIActive region corona2.5×106 K
30.4 nmHe IIChromosphere and transition region50,000 K
21.1 nmFe XIVActive region corona2×106 K
19.3 nmFe XII, XXIVCorona and hot flare plasma1.2×106 and 2x107 K
17.1 nmFe IXQuiet corona, upper transition region6.3×105 K
13.1 nmFe VIII, XX, XXIIIFlaring regions4×105, 107 and 1.6×107 K
9.4 nmFe XVIIIFlaring regions6.3×106 K

Photographs of the Sun in these various regions of the spectrum can be seen at NASA's SDO Data website.[19] Images and movies of the Sun seen on any day of the mission, including within the last half-hour, can be found at The Sun Today.

Communications

SDO down-links science data (K-band) from its two onboard high-gain antennas, and telemetry (S-band) from its two onboard omnidirectional antennas. The ground station consists of two dedicated (redundant) 18-meter radio antennas in White Sands Missile Range, New Mexico, constructed specifically for SDO. Mission controllers operate the spacecraft remotely from the Mission Operations Center at NASA Goddard Space Flight Center. 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 of data per day (equivalent to downloading around 500,000 songs).[7]

Launch

AttemptPlannedResultTurnaroundReasonDecision pointWeather go (%)Notes
110 Feb 2010, 3:26:00 pmScrubbed—Weather (high winds) [20]10 Feb 2010, 4:22 pm ​(T-3:59, immediately after T-4:00 hold)40% [21]window 10:26 to 11:26 EST, attempts made at 10:26, 10:56 and 11:26 EST
211 Feb 2010, 3:23:00 pmSuccess0 days, 23 hours, 57 minutes60% [21]Window: 10:23 to 11:23 EST

NASA's Launch Services Program at Kennedy Space Center managed the payload integration and launch.[22] The SDO launched from Cape Canaveral Space Launch Complex 41 (SLC-41), utilizing an Atlas V-401 rocket with a RD-180 powered Common Core Booster, which has been developed to meet the Evolved Expendable Launch Vehicle (EELV) program requirements.[23]

Sun dog phenomenon: Moments after launch, SDO's Atlas V rocket penetrated a cirrus cloud which created visible shock waves in the sky and destroyed the alignment of ice crystals that were forming a sun dog visible to onlookers.[24]

After launch, the spacecraft was deployed from the Atlas V into an orbit around the Earth with an initial perigee of about 2,500 km (1,600 mi).[25]

Transfer to final Orbit

Animation of Solar Dynamics Observatory's trajectory from 11 February 2010 to 11 April 2010
  Solar Dynamics Observatory ·   Earth

SDO then underwent a series of orbit-raising maneuvers over a few weeks which adjusted its orbit until the spacecraft reached its planned circular, geosynchronous orbit at an altitude of 35,789 km (22,238 mi), at 102° West longitude, inclined at 28.5°.[25] This orbit was chosen to allow 24/7 communications to/from the fixed ground station, and to minimise solar eclipses 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 for SDO. It is part of the Education and public outreach team and assists with various functions to help educate the public, mainly children, about the SDO mission, facts about the Sun and Space weather.[26] Camilla also assists in cross-informing the public about other NASA missions and space related projects. Camilla Corona SDO uses social media to interact with fans.

Stamps

USPS-issued forever stamps featuring images of the Sun

In 2021, the United States Postal Service released a series of forever stamps using images of the Sun taken by the Solar Dynamics Observatory. [27]

See also

References

  1. ↑ "SDO Our Eye on the Sun" (PDF). NASA. Retrieved 13 February 2010. Public Domain This article incorporates text from this source, which is in the public domain.
  2. ↑ Dean Pesnell; Kevin Addison (5 February 2010). "Solar Dynamics Observatory: SDO Specifications". NASA. Archived from the original on 30 January 2010. Retrieved 13 February 2010. Public Domain This article incorporates text from this source, which is in the public domain.
  3. ↑ "SDO 2010-005A". N2YO. 24 January 2015. Retrieved 25 January 2015.
  4. ↑ Bourkland, Kristin L.; Liu, Kuo-Chia (25 July 2011). Verification of the Solar Dynamics Observatory High Gain Antenna Pointing Algorithm Using Flight Data (Report). American Institute of Aeronautics and Astronautics. hdl:2060/20110015278.
  5. ↑ Justin Ray. "Mission Status Center: Atlas V SDO". Spaceflight Now. Retrieved 13 February 2010.
  6. ↑ Dean Pesnell; Kevin Addison (5 February 2010). "Solar Dynamics Observatory: About The SDO Mission". NASA. Archived from the original on 30 June 2007. Retrieved 13 February 2010. Public Domain This article incorporates text from this source, which is in the public domain.
  7. 1 2 3 "Solar Dynamics Observatory — Our Eye on the Sky" (PDF). NASA. 1 February 2010. Retrieved 13 February 2010. Public Domain This article incorporates text from this source, which is in the public domain.
  8. ↑ "Solar and Heliospheric Observatory Homepage". NASA /ESA. 9 February 2010. Retrieved 13 February 2010. Public Domain This article incorporates text from this source, which is in the public domain.
  9. ↑ "Solar Dynamics Observatory — Exploring the Sun in High Definition" (PDF). NASA. Retrieved 13 February 2010. Public Domain This article incorporates text from this source, which is in the public domain.
  10. ↑ Johnson-Groh, Mara (11 February 2020). "Ten Things We've Learned About the Sun From NASA's SDO This Decade". NASA. Retrieved 13 March 2020. Public Domain This article incorporates text from this source, which is in the public domain.
  11. ↑ Dean Pesnell; Kevin Addison (5 February 2010). "Solar Dynamics Observatory: SDO Instruments". NASA. Retrieved 13 February 2010. Public Domain This article incorporates text from this source, which is in the public domain.
  12. ↑ "Helioseismic and Magnetic Imager for SDO". Helioseismic and Magnetic Imager for SDO. 4 March 2011. Retrieved 12 November 2023.
  13. ↑ Solar Physics Research Group. "Helioseismic and Magnetic Imager Investigation". Stanford University. Retrieved 13 February 2010.
  14. ↑ "SDO – EVE-Extreme ultraviolet Variability Experiment". Laboratory for Atmospheric and Space Physics (LASP). 27 May 2010. Archived from the original on 16 July 2011. Retrieved 12 March 2020.
  15. 1 2 Woods, Tom (12 September 2007). "Extreme Ultraviolet Variability Experiment (EVE) on the Solar Dynamics Observatory (SDO) | Analogy on How the SDO EVE Measurements of the Solar Extreme Ultraviolet Irradiance will be Greatly Improved" (PDF). Laboratory for Atmospheric and Space Physics (LASP). Archived from the original (PDF) on 16 July 2011. Retrieved 22 September 2011.
  16. ↑ Rani Gran (7 September 2009). "First Solar Dynamic Observatory (SDO) Instrument Arrives at NASA Goddard Space Flight Center". NASA. Retrieved 17 February 2010. Public Domain This article incorporates text from this source, which is in the public domain.
  17. ↑ "AIA – Atmospheric Imaging Assembly". Lockheed Martin. 3 February 2010. Retrieved 14 February 2010.
  18. ↑ "Atmospheric Imaging Assembly – Descriptions and Manuals of Instruments, Data, and Software Packages". Lockheed Martin. Retrieved 27 June 2012.
  19. ↑ "Solar Dynamics Observatory". Goddard Space Flight Center. NASA. Retrieved 13 March 2020. Public Domain This article incorporates text from this source, which is in the public domain.
  20. ↑ Dunn, Marcia. "Stiff wind delays NASA launch of solar observatory". The Associated Press. Retrieved 10 February 2010.
  21. 1 2 "AFD-070716-027" (PDF). United States Airforce, 45th Weather Squadron. Archived from the original (PDF) on 13 June 2011. Retrieved 7 February 2010.
  22. ↑ "A New Eye on the Sun" (Press release). NASA. Archived from the original on 19 June 2010. Retrieved 13 February 2010. Public Domain This article incorporates text from this source, which is in the public domain.
  23. ↑ "SDO Launch Services Program" (PDF). Retrieved 13 February 2010. Public Domain This article incorporates text from this source, which is in the public domain.
  24. ↑ Phillips, Tony (11 February 2011). "SDO Sundog Mystery". NASA. Retrieved 13 March 2020. Public Domain This article incorporates text from this source, which is in the public domain.
  25. 1 2 Wilson, Jim (11 February 2010). "Solar Dynamics Observatory". Retrieved 13 February 2010. Public Domain This article incorporates text from this source, which is in the public domain.
  26. ↑ "Solar Dynamics Observatory". sdo.gsfc.nasa.gov. Archived from the original on 19 October 2011. Retrieved 3 May 2018. Public Domain This article incorporates text from this source, which is in the public domain.
  27. ↑ "The U.S. Postal Service to Issue NASA Sun Science Forever Stamps". NASA. 15 January 2021. Retrieved 19 January 2021. Public Domain This article incorporates text from this source, which is in the public domain.
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