SDO

SDO [NASA]

The SDO (Solar Dynamics Observatory) solar observing satellite will be a follow up to SOHO. SDO has four main goals:

• Research on the Solar Cycle.
• Identify the role of the magnetic field in delivering energy to the solar atmosphere and its many layers.
• Study how the outer regions of the Sun's atmosphere evolve over time - ranging from seconds to centuries - and space.
• Monitor the radiation (ex: UV, EUV, etc.) levels of solar output.

SDO will contain a suite of instruments which will provide the observations that will lead to a more complete understanding of the solar dynamics that drive variability in the Earth's environment. Following instruments are mounted on the spacecraft:

• HMI (Helioseismic and Magnetic Imager):
  The Helioseismic and Magnetic Imager will extend the capabilities of the SOHO/MDI instrument with continuous full-disk coverage at considerably higher spatial and temporal resolution line-of-sight magnetograms with the optional channel for full Stokes polarization measurements and hence vector magnetogram determination.
• AIA (Atmospheric Imaging Assembly):
  The Atmospheric Imaging Assembly will image the solar atmosphere in multiple wavelengths to link changes to surface and interior changes.
• EVE (Extreme Ultraviolet Variablity Experiment):
  The Extreme Ultraviolet Variablity Experiment will measure the solar Extreme-Ultraviolet (EUV) irradiance with unprecedented spectral resolution, temporal cadence, and precision.

The large data outtput (> 1 TByte/day) dictated the use of a geostationary orbit for continuous data downlink via a Ka-band transponder.