The SDO Mission
SDO: The Solar Dynamics Observatory is the first mission to be launched for NASA’s Living With a Star (LWS) Program, a program designed to understand the causes of solar variability and its impacts on Earth. SDO is designed to help us understand the Sun’s influence on Earth and Near-Earth space by studying the solar atmosphere on small scales of space and time and in many wavelengths simultaneously.
SDO’s goal is to understand, driving towards a predictive capability, the solar variations that influence life on Earth and humanity’s technological systems by determining
- 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.
- SDO launched on February 11, 2010, 10:23 am EST on an Atlas V from SLC 41 from Cape Canaveral.
Best of SDO Gallery
In the three years since it first provided images of the sun in the spring of 2010, NASA’s Solar Dynamics Observatory (SDO) has had virtually unbroken coverage of the sun’s rise toward solar maximum, the peak of solar activity in its regular 11-year cycle. This video shows those three years of the sun at a pace of two images per day. NASA’s Goddard Space Flight Center heliophysicist C. Alex Young highlights many interesting aspects of the Solar Dynamics Observatory (SDO) images and points out several of the single-frame events that appear in it.
VIdeo & photo credit: NASA Goddard Space Flight Center/SDO/SVS
Image Resolution Comparison
The following image illustrates the resolution capabilities of the SDO, STEREO, and SOHO spacecrafts. SDO’s AIA instrument (right image) has twice the image resolution than STEREO (middle image) and 4 times greater imaging resolution than SOHO (left image). The image cadence also varies. SDO takes 1 image every second. At best STEREO takes 1 image every 3 minutes and SOHO takes 1 image every 12 minutes.
Credit – http://sdo.gsfc.nasa.gov
SDO is helping us to understand the how and why of the Sun’s magnetic changes. It will determine how the magnetic field is generated and structured, and how the stored magnetic energy is released into the heliosphere and geospace. SDO data and analysis will also help us develop the ability to predict the solar variations that influence life on Earth and humanity’s technological systems.
SDO measures the properties of the Sun and solar activity. There are few types of measurements but many of them will be taken. For example, the surface velocity is measured by HMI. This data can be used for many different studies. One is the surface rotation rate, which must be removed to study the others. After subtracting the rotation, you have the oscillation and convective velocities. The latter look like billows of storm clouds covering the Sun. Hot gas moves outward at the center of the billows and downward at the edges, just like boiling water. By looking at these velocities you can see how sunspots affect the convection zone. By looking at a long sequence of data (more than 30 days), you see the oscillations of the Sun (like the picture). These patterns can be used to look into and through the Sun.
Mission Science Objectives
- The scientific goals of the SDO Project are to improve our understanding of seven science questions:
- What mechanisms drive the quasi-periodic 11-year cycle of solar activity?
- How is active region magnetic flux synthesized, concentrated, and dispersed across the solar surface?
- How does magnetic reconnection on small scales reorganize the large-scale field topology and current systems and how significant is it in heating the corona and accelerating the solar wind?
- Where do the observed variations in the Sun’s EUV spectral irradiance arise, and how do they relate to the magnetic activity cycles?
- What magnetic field configurations lead to the CMEs, filament eruptions, and flares that produce energetic particles and radiation?
- Can the structure and dynamics of the solar wind near Earth be determined from the magnetic field configuration and atmospheric structure near the solar surface?
- When will activity occur, and is it possible to make accurate and reliable forecasts of space weather and climate?
SDO contains a suite of instruments that provide observations that will lead to a more complete understanding of the solar dynamics that drive variability in the Earth’s environment. This set of instruments does the following:
- Measure the extreme ultraviolet spectral irradiance of the Sun at a rapid cadence
- Measure the Doppler shifts due to oscillation velocities over the entire visible disk
- Make high-resolution measurements of the longitudinal and vector magnetic field over the entire visible disk
- Make images of the chromosphere and inner corona at several temperatures at a rapid cadence
- Make those measurements over a significant portion of a solar cycle to capture the solar variations that may exist in different time periods of a solar cycle
The Science Teams receive the data from SDO. They then process, analyze, archive, and serve the data.
HMI (Helioseismic and Magnetic Imager)
- The Helioseismic and Magnetic Imager extends the capabilities of the SOHO/MDI instrument with continual full-disk coverage at higher spatial resolution and new vector magnetogram capabilities. PI: Phil Scherrer, PI Institution: Stanford University.
AIA (Atmospheric Imaging Assembly)
- The Atmospheric Imaging Assembly images the solar atmosphere in multiple wavelengths to link changes in the surface to interior changes. Data includes images of the Sun in 10 wavelengths every 10 seconds. PI: Alan Title, PI Institution: Lockheed Martin Solar Astrophysics Laboratory.
EVE (Extreme Ultraviolet Variablity Experiment)
- The Extreme Ultraviolet Variablity Experiment measures the solar extreme-ultraviolet (EUV) irradiance with unprecedented spectral resolution, temporal cadence, and precision. EVE measures the solar extreme ultraviolet (EUV) spectral irradiance to understand variations on the timescales which influence Earth’s climate and near-Earth space. PI: Tom Woods, PI Institution: University of Colorado.