Solar Dynamics Observatory

The Solar Dynamics Observatory (SDO) is a NASA mission under 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 Sun-Earth system that directly affect life and society.

General

The SDO mission is currently scheduled for launch January 26 2010. It is currently being tested in Building 7 at NASA's Goddard Space Flight Center in Greenbelt, Maryland. The primary mission is scheduled to last 5 years 3 months, with expendables expected to last for 10 years. Some consider SDO to be a follow-on mission to the Solar and Heliospheric Observatory (SOHO).

Communications

SDO will downlink science data (Ka-band) from its two onboard high-gain antennas, and engineering data (S-band) from its two onboard omni-directional antennas. The ground station consists of two dedicated (redundant) 18-meter radio antennas in White Sands, New Mexico. The antennas will be constructed specifically for SDO. The combined data rate will be about 130 Mbit/s (150 Mbit/s with overhead, or 300 Mbit/s 2:1 convolutinally encoded). SDO will generate approximately 1.5 Terabytes of data per day.

SDO will periodically use the Universal Space Network antenna at South Point, Hawaii to provide additional tracking resolution. Mission controllers will operate the spacecraft remotely from the Mission Operations Center at NASA's GSFC.

Launch vehicle

The launch vehicle is an Atlas V rocket. SDO will launch from NASA's Kennedy Space Center (KSC). The initial perigee will be about 2500 km, after which SDO will undergo a series of orbit-raising maneuvers until the nominal orbit is reached.

Spacecraft

SDO is a 3-axis stabilized spacecraft with two solar arrays and two high-gain antennas.

Orbit

SDO will orbit at 36,000 km in a circular geosynchronous orbit at 102° W longitude inclined at 28.5°.

Science instruments

The science instruments on SDO are:

The Extreme Ultraviolet Variability Experiment

The Extreme Ultraviolet Variability Experiment (EVE), led from the University of Colorado's Laboratory for Atmospheric and Space Physics (LASP) in Boulder, CO, measures the solar EUV irradiance with unprecedented spectral resolution, temporal cadence, accuracy, and precision.

The Helioseismic and Magnetic Imager

The Helioseismic and Magnetic Imager (HMI), led from Stanford University in Stanford, CA, studies solar variability and characterizes the Sun’s interior and the various components of magnetic activity.

The Atmospheric Imaging Assembly

The Atmospheric Imaging Assembly (AIA), led from the Lockheed Martin Solar and Astrophysics Laboratory (LMSAL), provides full-disk imaging of the Sun in several ultraviolet and Extreme-Ultraviolet (EUV) band passes at high spatial and temporal resolution.

References

External links

• SDO mission website
• Solar Dynamics Observatory Mission Profile by NASA's Solar System Exploration