Low Cost Asses to Space-CAL-SO Program and Continuation and Improvement of the SOHO CELIAS/SEM Data Base
The SOHO CAL-SO program funded by the Low Cost Access to Space NASA grant NNG05WC09G is in the year of no-cost-extension. Thus far under this grant we have had two successful rocket underflights that return high quality EUV data and three successful calibrations of the SEM instrument at NIST. Analysis of the data from all underflights was completed in Dec 2008. The results will be presented at the Fall AGU Meeting (San Francisco, Dec 2008): Darrell Judge, Leonid Didkovsky, Seth
Wieman, and Pradip Gangopadhyay. "13 Years of SOHO/CELIAS/SEM Calibrated Solar Extreme Ultraviolet Irradiance Data". The SEM calibrated data website at USC (http://www.usc.edu/dept/space_science) will be updated in Dec 2008 - Jan 2009 to publish the new version of the SEM data (Ver 3.1 of Dec 11, 2008). This work was partially supported by NASA grant NNG05WC09G; USC# 53-4882-3600 and NASA grant NASA-NNX08AM94G; USC# 53-4882-2820
The ESP flight and rocket instruments have been successfully calibrated at NIST and delivered to LASP and later to Goddard SFC. The flight instrument was assembled to the EVE and is a part of SDO. SDO was launched on Feb 12, 2010.
A New Advanced Extreme Ultraviolet Optics Free Spectrometer
The Space Sciences Center is currently working (year two of two) on the Project to design and build a new OFS (NASA grant NASA-NNX07AN37G; USC# 53-4882-4640). The laboratory design is about to be fabricated at the USC mechanical shop. After assembling the focusing system, laboratory tests
with EUV monochromator will begin in Jan 2009.
Degradation-Free Spectrometers (DFS) for Solar Physics (NASA-NNX08BA12G; USC# 53-4882-5920)
A Sounding Rocket flights NASA 36.263 Judge and NASA 36.289 Didkovsky with four USC EUV instruments onboard
Payload. Some 36.289 details, see the information board,
36.289_Info 36.289 Team group photo next to the launch pad,
36.289_Team and the first second of the launched rocket
successfully launched from WSMR on 24 July 2012 (36.263) and on 22 July 2014 (36.289).
The instruments for measuring solar absolute EUV irradiance included the Solar Extreme_ultraviolet Monitor
(SEM) - a clone of the SOHO/CELIAS/SEM
flight instrument, the Rare Gas Ionization Cell
(RGIC) - an extremely stable Ne-gas ionization instrument which served for a long time
as a secondary standard of EUV irradiance at NIST,
the Optics-Free Spectromeer (OFS)
, and the Dual-Grating Spectrometer (DGS).
The 36.289 was the second flight of the two latter instruments, both novel degradation-free spectrometers, while the SEM and RGIC data are used for
calibration of existing EUV flight measurements, such as the SOHO/CELIAS/SEM and the SDO/EVE/ESP.
The flight 36.289 met this observational challenge and the comprehensive success criteria. The data from the flights
will be analyzed soon [Didkovsky et al., AGU Fall Meeting, San Francisco, 2014].
An important outcome of the flight is the confirmation of the robustness of the DGS
filter-free design for observing solar EUV spectral lines of interest without degradation, e.g. the He II 30.4 nm line
which has been widely used by the solar and Earth's atmosphere communities since 30.4 nm data became available from
the SOHO/CELIAS/SEM. The OFS, which measures EUV wavlength spectra based on energy analysis of photoelectrons from Ne target gas, was
calibrated at the NIST/SURF synchrotron prior to flight.
OFS spectra of monochromatic EUV radiation from the NIST synchrotron at several different wavelengths show its ability to resolve spectral lines in the EUV. Once the OFS response to solar EUV is known, spectral resolution of the instrument can be further optimized.