Glaring at the Sun with NASA’s SDO
CAPE CANAVERAL, Fla., Feb. 11, 2010 – At approximately 10:30 Eastern today, NASA launched its Solar Dynamics Observatory (SDO), the first of the space agency’s “Living with a Star” programs to blast-off. The programs are intended to study and understand the causes of solar variability and the effect such changes have on Earth and on near-Earth space.
NASA’s Solar Dynamics Observatory (SDO) includes a package of instruments that will collect data on the solar dynamics that drive variations in the Earth’s environment. Photo courtesy of NASA.
The SDO spacecraft is designed to examine the evolution of solar activity and to refine our understanding of space weather by studying the sun on small scales of space and time and in many wavelengths simultaneously. To do this, SDO has three scientific instruments on board; the Atmospheric Imaging Assembly (AIA), the EUV Variability Experiment (EVE), and the Helioseismic and Magnetic Imager (HMI). The HMI and AIA instruments, which were both built by the Lockheed Martin Solar and Astrophysics Laboratory (LMSAL), include image sensors made by e2v technologies plc of Chelmsford, UK.
Four specially processed back-illuminated e2v CCD203-82 (4000 × 4000-pixel) sensors sensitive to extreme-UV wavelengths are incorporated into the four AIA telescopes, which will observe the sun in the wavelength range of 9.4 to 170 nm. The AIA instrument is under the direction of Alan Title at LMSAL, and will use solar images taken in multiple wavelengths to study the energetics of the solar atmosphere and it’s interaction with the surface magnetic fields.
Back- and front-illuminated versions of e2v technologies’ CCD203-82 extreme-UV sensors are being used in NASA’s Solar Dynamics Observatory mission. Photo courtesy of e2v technologies plc.
Two front-illuminated CCD203-82 sensors are used in the HMI instrument to image the sun in visible light at 617 nm. The HMI instrument is under the direction of Philip Scherrer at Stanford University in California, and will measure both solar surface magnetic fields and the sun’s surface motion as a probe of the solar interior.
Though the performance was optimized for each instrument, all CCDs have the same electrical format and were designed to operate at lower voltages than normal. This facilitates provision of drive electronics and also reduces the power demand on the spacecraft. The camera electronics were built in the UK by e2v technologies’ project partners at the Rutherford Appleton Laboratory in Didcot, UK.
According to Jon Kemp, e2v technologies’ general manager of space and defence imaging, the launch of SDO marks the third time in recent months that sensors made by the company have contributed to US space programs, including the Kepler mission and the Hubble upgrade.
For more information, visit: www.e2v.com
- back-illuminated ccd
- A CCD that has been reduced in thickness by etching so that light passes through the back layers of the CCD. This type of CCD typically has higher sensitivity, especially to blue light, and higher quantum efficiency than front-illuminated CCDs, because the light is not required to pass through the CCD's gate structure.
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