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Register a new userQuality control of the CFRP mirror manufacturing process at NPF
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The surface quality of replicated CFRP mirrors is ideally expected to be as good as the mandrel from which they are manufactured. In practice, a number of factors produce surface imperfections in the final mirrors at different scales. To understand where this errors come from, and develop improvements to the manufacturing process accordingly, a wide range of metrology techniques and quality control methods must be adopted. Mechanical and optical instruments are employed to characterise glass mandrels and CFRP replicas at different spatial frequency ranges. Modal analysis is used to identify large scale aberrations, complemented with a spectral analysis at medium and small scales. It is seen that astigmatism is the dominant aberration in the CFRP replicas. On the medium and small scales, we have observed that fiber print-through and surface roughness can be improved significantly by an extra resin layer over the replicas surface, but still some residual irregularities are present.
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Planet Formation research is blooming in an era where we are moving from speaking about protoplanetary disks to planet forming disks (Andrews et al., 2018). However, this transition is still motivated by indirect (but convincing) hints. Up to date, the direct detection of planets in the making remains elusive with the remarkable exception of PDS70b and c (Haffert et al., 2019; Keppler et al., 2018; Muller et al., 2018). The scarcity of detections is attributable to technical challenges, and even for the rare jewels that we can detect, characterization (resolving their hill spheres) is unachievable. The next step in this direction demands from near to mid-infrared interferometry to jump from $sim$100 m baselines to $sim$1 km, and from very few telescopes (two to six) to 20 or more (PFI like concepts, Monnier et al. 2018). This transition needs for more affordable near to mid-infrared telescopes to be designed. Since the driving cost for such telescopes resides on the primary mirror, in particular scaling with its diameter and weight, our approach to tackle this problem relies on the production of low-cost light mirrors.
In the manufacturing process of Carbon Fiber Reinforced Polymer (CFRP) mirrors (replicated from a mandrel) the orientation of the unidirectional carbon fiber layers (layup) has a direct influence on different aspects of the final product, like its general (large scale) shape and local deformations. In particular, optical methods used to evaluate the surfaces quality, can reveal the presence of print-through, a very common issue in CFPR manufacture. In practical terms, the surfaces irregularities induced, among other artifacts, by print-through, produce unwanted scattering effects, which are usually mitigated applying extra layers of different materials to the surface. Since one of the main goals of CFPR mirrors is to decrease the final weight of the whole mirror system, adding more material goes in the opposite direction of that. For this reason a different layup method is being developed with the goal of decreasing print-through and improving sphericity while maintaining mechanical qualities and without the addition of extra material in the process.
In the framework of the GLARE-X (Geodesy via LAser Ranging from spacE X) project, led by INFN and funded for the years 2019-2021, aiming at significantly advance space geodesy, one shows the initial activities carried out in 2019 in order to manufacture and test adaptive mirrors. This specific article deals with manufacturing and surface quality measurements of the passive substrate of candidate MEMS (Micro-Electro-Mechanical Systems) mirrors for MRRs (Modulated RetroReflectors); further publications will show the active components. The project GLARE-X was approved by INFN for the years 2019-2021: it involves several institutions, including, amongst the other, INFN-LNF and FBK. GLARE-X is an innovative R&D activity, whose at large space geodesy goals will concern the following topics: inverse laser ranging (from a laser terminal in space down to a target on a planet), laser ranging for debris removal and iterative orbit correction, development of high-end ToF (Time of Flight) electronics, manufacturing and testing of MRRs for space, and provision of microreflectors for future NEO (Near Earth Orbit) cubesats. This specific article summarizes the manufacturing and surface quality measurements activities performed on the passive substrate of candidate MEMS mirrors, which will be in turn arranged into MRRs. The final active components, to be realized by 2021, will inherit the manufacturing characteristics chosen thanks to the presented (and further) testing campaigns, and will find suitable space application to NEO, Moon, and Mars devices, like, for example, cooperative and active lidar scatterers for laser altimetry and lasercomm support.
The Astronomical Roentgen Telescope X-ray Concentrator (ART-XC) is a hard X-ray telescope with energy response up to 30 keV, to be launched on board the Spectrum Roentgen Gamma (SRG) spacecraft in 2018. ART-XC consists of seven identical co-aligned mirror modules. Each mirror assembly is coupled with a CdTe double-sided strip (DSS) focal-plane detector. Eight X-ray mirror modules (seven flight and one spare units) for ART-XC were developed and fabricated at the Marshall Space Flight Center (MSFC), NASA, USA. We present results of testing procedures performed with an X-ray beam facility at MSFC to calibrate the point spread function (PSF) of the mirror modules. The shape of the PSF was measured with a high-resolution CCD camera installed in the focal plane with defocusing of 7 mm, as required by the ART-XC design. For each module, we performed a parametrization of the PSF at various angular distances Theta. We used a King function to approximate the radial profile of the near on-axis PSF (Theta<9 arcmin) and an ellipse fitting procedure to describe the morphology of the far off-axis angular response (9<Theta<24 arcmin). We found a good agreement between the seven ART-XC flight mirror modules at the level of 10%. The on-axis angular resolution of the ART-XC optics varies between 27 and 33 arcsec (half-power diameter), except for the spare module.
The Kilo Degree Survey (KiDS) is a 1500 square degree optical imaging survey with the recently commissioned OmegaCAM wide-field imager on the VLT Survey Telescope (VST). A suite of data products will be delivered to ESO and the community by the KiDS survey team. Spread over Europe, the KiDS team uses Astro-WISE to collaborate efficiently and pool hardware resources. In Astro-WISE the team shares, calibrates and archives all survey data. The data-centric architectural design realizes a dynamic live archive in which new KiDS survey products of improved quality can be shared with the team and eventually the full astronomical community in a flexible and controllable manner
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