header image 2

University of Southern California

Mission Overview    

The Extreme ultraviolet Spectrometer (ESP) is one of several EUV instruments that will be onboard the Solar Dynamic Observatory (SDO) which 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 is currently schedule for launch into geo-synchronous in August of 2008.

Goals and Objectives of SDO

  • Understand how magnetic fields appear, distribute, and disappear from their origin in the solar interior
  • Understand the magnetic topologies that give rise to rapid high-energy release processes
  • Study and gauge the dynamic processes which influence space weather phenomena
  • Study the variations in irradiance and solar structure which occur on short timescales, as well as over the solar cycle. -NASA


    The Extreme Ultraviolet Spectrometer (ESP) instrument, part of the Solar Dynamic Observatory (SDO) EUV Experiment (EVE) instrument suite is a direct descendent of the Solar Orbiting Heliospheric Observatory/Solar Extreme Ultraviolet Monitor (SOHO/SEM) instrument now orbiting the Sun one million miles from Earth using the same Extreme Ultraviolet (EUV) transmission grating technology developed at MIT.

    The ESP will provide a stable reference for EVE/Multiple Euv Grating Spectrograph (MEGS) Spectrometers with 5 wavelength bands covering 0.1nm-64nm (centered on 17.1nm, 25.7nm, 30.4nm, 36.0nm and the central order) and will provide a fast, stable and accurate data product for Space Weather (0.25 s integration time with a simple calibration). The science data obtained from the EVE instrument suite will help provide valuable information about the varibility of the solar irradiance and solar structure which occur on short times scales, as well as over the solar cycle.

    The schematic in the right panel shows a section view from the top of the ESP instrument. From front to back, (1) the gray feature is the filter wheel, (2) the light blue feature is the case, (3) the teal blue feature is an Al filter, (4) the red feature is the tramission grating, (5) the yellow lines represent EUV diffracted through the transmission grating to the (6) detector plane rendered in lime green which includes 5 AXUV diodes, two on either side of a quadrant diode in the center and just to the left a dark diode. Shown in olive green is a filter. Behind the detector plane shown in green are the (7) electrometers (the green lines) and the (8) mother board (the green rectangle).

        website last updated 5/31/2007