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SAFIR is a set of scientific objectives aiming to answer key questions in astrophysics through far-infrared measurements. This report discusses the concept development, programmatic status, outreach, science developments, and technology needs for SAFIR.
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SAFIR:Single Aperture Far-InfraRed ObservatoryNASA/GSFC Project Status Dominic Benford (with contributions from many others)
What SAFIR Is… and Isn’t SAFIR is best thought of as a set of scientific objectives that answer key questions in astrophysics by means of measurements in the far-infrared. Its implementation is yet to be determined. Concept development needed.
Programmatic Status • History: • HQ commissioned JPL/GSFC/external SAFIR Science Working Group; met in July • GSFC Concept based on JWST developed • GSFC Status: • $50K from HQ supported GSFC in FY02; GSFC donated $75K of internal money to supplement • Ready & willing to continue working with JPL to mature the mission concepts, but support and guidance from HQ is requested.
Outreach Developments • Presented 3 papers at SPIE meeting in Kona "Single Aperture Far-Infrared Observatory (SAFIR)" P. M. Harvey, G. H. Rieke, D. F. Lester & D.J. Benford "An Engineering Concept and Enabling Technologies for a Large Single Aperture Far-IR Observatory (SAFIR)" M. J. Amato, S. H. Moseley, D. J. Benford & J. Roman "Ultralow-Background Large-Format Bolometer Arrays" D. J. Benford, J. A. Chervenak, S.H. Moseley & K. D. Irwin • Web Sites (GSFC to be combined with JPL’s): safir.gsfc.nasa.gov safir.jpl.nasa.gov
Science Developments • Produced list of top priority science projects • Flowed down measurments, mission/technology requirements • Published at SPIE (Harvey et al., Amato et al.) • Modeled SAFIR performance • Determined instrument complement necessary for science observations
Parameter Requirement Driving Science Aperture > 8m High z Galaxies; Debris Disks Temperature ~ 4K Spectroscopy; L* Galaxy@ z ~ 5 Wavelength Range 20-800mm NGST Overlap; Gas Cooling Lines Diffraction Limit l≥40mm (1”) Debris Disks; Distant Galaxies Pointing Accuracy 0.5 – 1” Driven by 40mm diffraction limit Pointing Stability ~ 0.1” Driven by 40mm diffraction limit Lifetime > 5 years Productivity Telescope Requirements
Instrument l range Spectral Resolution FOV Driving Science Camera 20 - 600mm ~ 5 1-4’ High z reddening KBO’s Spectrometer 20 - 100mm ~ 100 ~10” Img Slicer Debris Disks; YSO’s Spectrometer 20 - 800mm ~ 2000 ~ 1’ C+; N+; Chemical Evolution Spectrometer 25 - 520mm ~106 > 1 beam Dynamics; Gas Cooling Strawman Instrumentation
GSFC Mission Concept JWST-based Concept
Thermal Control Amato et al., SPIE
Mission Deployments Amato et al., SPIE
GSFC Alternate Concepts Petal-deployed Concept Sparse Aperture Concept
Cryogenic cooling: Radiative to ~30K Refrigerators to ~6K (optics @4K) Refrigerator <1K (detectors ~0.1K) Support structures: Deployable optics Deployable sunshade Low thermal conductance S/C-to-telescope support Lightweight, large optics: Larger than JWST Lighter than JWST Colder than JWST Detectors: Wavelengths 20-600µm Large format direct detector arrays (1k-10k pixels) Coherent receivers Technology Needs • But less demanding figure! • Infrastructure: • Manufacturing capability • Testing Facilities • Flight Heritage: MAP, SIRTF, JWST, Herschel, SOFIA (& suborbital), Con-X
Summary • SAFIR is a high priority mission for the astronomical community. • JPL+GSFC+external community organized into SWG to oversee SAFIR’s overall direction. • GSFC has developed mission concept • high fidelity, complete concept; • followed from requirements flowdown through implementation; • is technically feasible. • Further HQ direction?