NASA sounding rocket 36.240 was launched from White Sands Missile Range in New Mexico on 14 April 2008. The primary instrument in this payload was the prototype extreme ultraviolet (EUV) Variability Experiment (EVE). The Multiple EUV Grating Spectrograph (MEGS) channels of EVE measure the solar irradiance from 6 to 106 nm at 0.1 nm spectral resolution. While the main purpose of this rocket flight is to provide the fifth underflight calibration for the Solar EUV Experiment (SEE), the importance of this rocket observation is the first observation of the solar EUV irradiance at high spectral resolution during solar cycle minimum conditions. The higher spectral resolution measurements will help resolve outstanding concerns about the previous solar soft X‐ray irradiance results made with broadband photometers shortward of 27 nm, and the measurements provide the most accurate reference for the solar cycle minimum as part of the international Whole Heliosphere Interval (WHI) campaign.
The NASA Solar Dynamics Observatory (SDO), scheduled for launch in early 2010, incorporates a suite of instruments including the Extreme Ultraviolet Variability Experiment (EVE). EVE has multiple instruments including the Multiple Extreme ultraviolet Grating Spectrographs (MEGS) A, B, and P instruments, the Solar Aspect Monitor (SAM), and the Extreme ultraviolet SpectroPhotometer (ESP). The radiometric calibration of EVE, necessary to convert the instrument counts to physical units, was performed at the National Institute of Standards and Technology (NIST) Synchrotron Ultraviolet Radiation Facility (SURF III) located in Gaithersburg, Maryland. This paper presents the results and derived accuracy of this radiometric calibration for the MEGS A, B, P, and SAM instruments, while the calibration of the ESP instrument is addressed by Didkovsky et al. (Solar Phys., 2010, doi:10.1007. In addition, solar measurements that were taken on 14 April 2008, during the NASA 36.240 sounding-rocket flight, are shown for the prototype EVE instruments.
Recognizing that the solar extreme ultraviolet (EUV) irradiance is an important driver of space weather, the National Oceanic and Atmospheric Administration (NOAA) has added an Extreme Ultraviolet Sensor (EUVS) to its Geostationary Operational Environmental Satellite (GOES) program, starting with the recently launched GOES-N, now designated GOES-13. For the GOES-R series (slated for launch starting in 2015) , the EUVS measurement concept has been redesigned. Instead of measuring broad bands spanning the EUV, the GOES-R EUVS will measure specific solar emissions representative of coronal, transition region, and chromospheric variability. From these measurements, the geo-effective EUV wavelength range from 5 to 127 nm can be reconstructed using models based on spectrally resolved measurements gathered over the full range of solar variability. An overview of the GOES-R EUVS design is presented. A description of the in-flight degradation tracking utilizing similar measurement and modeling techniques used to generate the EUV irradiance is also provided.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.