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Fabricating High Resolution Mirrors for Hand X-Ray AstronomyWe describe the fabrication process for producing high-resolution conical mirrors for hard x-ray astronomy. When flown aboard stratospheric balloons, these high-resolution reflective mirrors focus hard x-rays (10-70 keV) emitted from cosmic sources such as supernovae, neutron stars, and quasars onto imaging focal plane detectors. Focused hard x-ray images allow scientists to determine the elemental compositions, temperatures, magnetic fields, velocities, and gravitational fields of these celestial bodies. The fabrication process involves generating super-polished mandrels, mandrel metrology, mirror shell nickel electroforming, and mirror testing. Each mandrel is a cylinder consisting of two conical segments; each segment is approximately 305-mm long. Through precision grinding these mandrels before super polishing, we have achieved 30 arc seconds, half power diameter replicated mirrors. During a May 2001 high atmosphere balloon flight, these mirrors focused high energy x-rays from three different celestial sources. However, we seek to improve the angular resolutions of future mirror shells by a factor of two. To achieve this goal, we have begun single point diamond turning the mandrels before super polishing. This has allowed greater precision tolerances on mandrel surface roughness and axial figure errors before super polishing. Surface roughnesses before polishing have been reduced from approximately 60 nm to approximately 15 nm. The peak to valley axial figure profile errors have been reduced from approximately 1.0 micrometers to approximately 0.4 micrometers. We are currently in Phase 2 of the HERO (high energy replicated optics) program which entails the production of sixteen 6-m-focal-length mirror modules, each containing a nested array of 15 mirror shells of diameters ranging from 50-mm to 94-mm. This flight is slated for the fall of 2003.
Document ID
20020024747
Acquisition Source
Marshall Space Flight Center
Document Type
Preprint (Draft being sent to journal)
Authors
Speegle, Chet O.
(Raytheon Information Technology and Scientific Services Huntsville, AL United States)
Ramsey, Brian D.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Engelhaupt, Darell
(Alabama Univ. Huntsville, AL United States)
Six, N. Frank
Date Acquired
August 20, 2013
Publication Date
January 1, 2001
Subject Category
Astronomy
Meeting Information
Meeting: OSA Optics in the Southeast
Location: Clemson, SC
Country: United States
Start Date: October 4, 2001
End Date: October 5, 2001
Sponsors: Optical Society of America
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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