We present results of the point spread function (PSF) calibration of the hard X-ray optics of the Nuclear Spectroscopic Telescope Array (NuSTAR). Immediately post-launch, NuSTAR has observed bright point sources such as Cyg X-1, Vela X-1, and Her X-1 for the PSF calibration. We use the point source observations taken at several off-axis angles together with a ray-trace model to characterize the in-orbit angular response, and find that the ray-trace model alone does not fit the observed event distributions and applying empirical corrections to the ray-trace model improves the fit significantly. We describe the corrections applied to the ray-trace model and show that the uncertainties in the enclosed energy fraction (EEF) of the new PSF model is (approximately less than) 3% for extraction apertures of R (approximately greater than) 60″ with no significant energy dependence. We also show that the PSF of the NuSTAR optics has been stable over a period of ~300 days during its in-orbit operation.
The Nuclear Spectroscopic Telescope Array (NuSTAR) mission was launched on 2012 June 13 and is the first focusing high-energy X-ray telescope in orbit operating above ~10 keV. NuSTAR flies two co-aligned Wolter-I conical approximation X-ray optics, coated with Pt/C and W/Si multilayers, and combined with a focal length of 10.14 meters this enables operation from 3-79 keV. The optics focus onto two focal plane arrays, each consisting of 4 CdZnTe pixel detectors, for a field of view of 12.5 arcminutes. The inherently low background associated with concentrating the X-ray light enables NuSTAR to probe the hard X-ray sky with a more than 100-fold improvement in sensitivity, and with an effective point spread function FWHM of 18 arcseconds (HPD ~1), NuSTAR provides a leap of improvement in resolution over the collimated or coded mask instruments that have operated in this bandpass. We present in-orbit performance details of the observatory and highlight important science results from the first two years of the mission.
We describe the fabrication of the two NuSTAR flight optics modules. The NuSTAR optics modules are glass-graphiteepoxy
composite structures to be employed for the first time in space-based X-ray optics by NuSTAR, a NASA Small
Explorer schedule for launch in February 2012. We discuss the optics manufacturing process, the qualification and
environmental testing performed, and briefly discuss the results of X-ray performance testing of the two modules. The
integration and alignment of the completed flight optics modules into the NuSTAR instrument is described as are the
optics module thermal shields.
NuSTAR is a hard X-ray satellite experiment to be launched in 2012. Two optics with 10.15 m focal length focus Xrays
with energies between 5 and 80 keV onto CdZnTe detectors located at the end of a deployable mast. The FM1 and
FM2 flight optics were built at the same time based on the same design and with very similar components, and thus the
performance of both is expected to be very similar. We provide an overview of calibration data that is being used to
build an optics response model for each optic and describe initial results for energies above 10 keV from the ground
calibration of the flight optics. From a preliminary analysis of the data, our current best determination of the overall
HPD of both the FM1 and FM2 flight optics is 52", and nearly independent of energy. The statistical error is negligible,
and a preliminary estimate of the systematic error is of order 4". The as-measured effective area and HPD meet the toplevel
NuSTAR mission sensitivity requirements.
The Nuclear Spectroscopic Telescope Array (NuSTAR) is a NASA Small Explorer mission that will carry the first focusing hard X-ray (6 - 80 keV) telescope to orbit. NuSTAR will offer a factor 50 - 100 sensitivity improvement compared to previous collimated or coded mask imagers that have operated in this energy band. In addition, NuSTAR provides sub-arcminute imaging with good spectral resolution over a 12-arcminute eld of view. After
launch, NuSTAR will carry out a two-year primary science mission that focuses on four key programs: studying the evolution of massive black holes through surveys carried out in fields with excellent multiwavelength coverage, understanding the population of compact objects and the nature of the massive black hole in the center of the Milky Way, constraining the explosion dynamics and nucleosynthesis in supernovae, and probing the nature of particle acceleration in relativistic jets in active galactic nuclei. A number of additional observations will be included in the primary mission, and a guest observer program will be proposed for an extended mission to expand the range of scientic targets. The payload consists of two co-aligned depth-graded multilayer coated grazing incidence optics focused onto a solid state CdZnTe pixel detectors. To be launched in early 2012 on a Pegasus rocket into a low-inclination Earth orbit, NuSTAR largely avoids SAA passage, and will therefore have low and
stable detector backgrounds. The telescope achieves a 10.14-meter focal length through on-orbit deployment of an extendable mast. An aspect and alignment metrology system enable reconstruction of the absolute aspect and variations in the telescope alignment resulting from mast exure during ground data processing. Data will
be publicly available at GSFC's High Energy Archive Research Center (HEASARC) following validation at the science operations center located at Caltech.
The Nuclear Spectroscopic Telescope Array (NuSTAR) is a NASA Small Explorer mission scheduled for launch in
February 2012. NuSTAR will deploy two imaging CdZnTe spectrometers in the 6-79 keV energy band. The two
NuSTAR optics utilize multilayer-coated, thermally-slumped glass integrated into a titanium-glass-epoxy-graphite
composite structure, along with an extendable mast, to obtain 10.15 meter focal length. Using this approach, the
NuSTAR optics will obtain subarcminute imaging with large effective area over its entire energy band. NuSTAR's
conic-approximation Wolter-I optics are the first true hard X-ray focusing optics to be deployed on a satellite
experiment. We report on the design of the NuSTAR optics, present the status of the two flight optics under
construction, and report preliminary measurements that can be used to predict performance.
The Nuclear Spectroscopic Telescope Array (NuSTAR) is a NASA Small Explorer (SMEX) mission which employs two
focusing optics. The optics are composed of stacks of thin mirror shells and spacers. Epoxy is used to bond the mirror
shells to the spacers and is a crucial component in determining the structural and optical performance of the telescopes.
We describe the epoxy selection for NuSTAR optics, emphasizing those epoxy characteristics essential to obtaining good
The Nuclear Spectroscopic Telescope Array (NuSTAR) is a NASA satellite mission scheduled for launch in 2011. Using focusing optics with multilayer coating for enhanced reflectivity of hard X-rays (6-79 keV), NuSTAR will provide a combination of clarity, sensitivity and spectral resolution surpassing the largest observatories in this band by orders of magnitude. This advance will allow NuSTAR to test theories of how heavy elements are born, discover collapsed stars and black holes on all scales and explore the most extreme physical environments. We will present an overview of the NuSTAR optics design and production process and detail the optics performance.