Described is the M1 segment support, as designed by TNO in the period 2015-2016. The design has significantly changed and improved compared to the earlier designs. During the period 2009-2010 prototypes for the primary mirror support of the E-ELT have been developed. These have been extensively tested by ESO. Design improvement were found to be necessary, especially in the field of manufacturability and maintainability. Furthermore, the technical performance had to improve in specific areas as well. This has evolved into a new specifications which have resulted in a new design for the segment support structure. The design rules that have led to the prototype design have been maintained but the implementation has been much improved. Also considerable improvement has been obtained with respect to the dynamic behavior. Accessibility and visibility on all parts and subsystems has changed such that everything is now clearly visible. Despite the increased performance no mass increase has been recorded meaning that more efficient use has been made of the material.
The active means to influence the segment shape by use of the warping harness has been completely redesigned. A very important quality that has been achieved is simplicity. Hence a minimum amount of components is used. Reliability and safety are other aspects that have been greatly improved compared to the prototypes. The design for the M1 segment support provides a solution that not only performs to specification but one that can be operated in a telescope environment, all 798 of them.
A lightweight, single-aperture, and multispectral imaging system operating from visible to long wavelength infrared has been manufactured and tested based on an innovative three-mirror anastigmat optical design. The complex off-axis aspherical toroidal mirrors of the optics have been obtained by electroforming replication from masters having a shape opposite to the mirror shape and manufactured as stand-alone parts by using five-axis single-point diamond turning. The technology is extendible to full free-form optics without any process modification enabling affordability of complex optics since multiple identical copies of the mirrors can be produced from each master. Moreover, thin (∼1 mm ) electroformed mirrors keep the imaging system mass less than 3 kg . With an effective focal length of 136 mm, the system is suitable for airborne surveillance applications and provides a full aperture F/# of 1.4, a field of view of 4.3×3.1 deg , and a nominal contrast better than 75% in the visible waveband at 25 cycles/mm . A beam splitter can be accommodated to provide two separated channels for two or more spectral wavebands. Stray light and thermostructural design has been performed to comply with airborne applications. Experimental results demonstrate the feasibility of the technology, although process improvements are required to reach the extremely demanding theoretical performance of the optical design.
A lightweight single-aperture and multi-spectral sensor operating from Visible to LWIR has been designed, manufactured and tested exploiting a Three Mirror Anastigmat (TMA) telescope featuring thin free-form mirrors electroformed from negative masters. Manufacturing complexity is in place only for the master realization, the contribution of which to the sensor cost decreases with the number of replicas. The TMA, suitable for airborne surveillance applications, has F/no. 1.4, focal length 136 mm and field of view 4.3° × 3.1°, and provides two channels, in the MWIR-LWIR and in the visible waveband. The nominal contrast is better than 75% in the visible at 25 cycles/mm. Electroformed 1 mm thick mirrors keep the sensor mass below 3 kg. Stray light and thermo-structural design has been done to comply with airborne conditions.
This paper presents the huge advance in metrology represented by a new free-form profilometer, the
Profilometer/Rotondimeter (MPR-700). The MPR-700 is a 3D metrological machine capable to measure quasicylindrical
and free-form normal incidence optics maintaining the 2D measuring error below 40 nm at 2σ up to a length
of 700 mm. The key to success of MPR is its innovative detection system design that boasts remarkable advantages in
the positioning error reduction and to the instantaneous subtraction of the dynamical error. These characteristics make
the MPR extremely precise and accurate, insomuch that measurements can be acquired in flight at high speed
maintaining the measuring performances. The main advantage of the MPR design is the capability to couple the
measuring quality offered by one-dimensional profilometer to the opportunity to the three-dimensional motion of a 3D
machines. Here we present the MPR design and the results obtained on single profiles measurements and 3D shape
reconstruction for optics of different geometry.
KEYWORDS: Mirrors, Point spread functions, X-rays, Hard x-rays, X-ray optics, X-ray telescopes, Spatial resolution, Metrology, Near field diffraction, Sensors
The realization of X-ray telescopes with imaging capabilities in the hard (> 10 keV) X-ray band requires the adoption of
optics with shallow (< 0.25 deg) grazing angles to enhance the reflectivity of reflective coatings. On the other hand, to
obtain large collecting area, large mirror diameters (< 350 mm) are necessary. This implies that mirrors with focal
lengths ≥10 m shall be produced and tested. Full-illumination tests of such mirrors are usually performed with onground
X-ray facilities, aimed at measuring their effective area and the angular resolution; however, they in general
suffer from effects of the finite distance of the X-ray source, e.g. a loss of effective area for double reflection. These
effects increase with the focal length of the mirror under test; hence a "partial" full-illumination measurement might not
be fully representative of the in-flight performances. Indeed, a pencil beam test can be adopted to overcome this
shortcoming, because a sector at a time is exposed to the X-ray flux, and the compensation of the beam divergence is
achieved by tilting the optic. In this work we present the result of a hard X-ray test campaign performed at the BL20B2
beamline of the SPring-8 synchrotron radiation facility, aimed at characterizing the Point Spread Function (PSF) of a
multilayer-coated Wolter-I mirror shell manufactured by Nickel electroforming. The mirror shell is a demonstrator for
the NHXM hard X-ray imaging telescope (0.3 - 80 keV), with a predicted HEW (Half Energy Width) close to 20
arcsec. We show some reconstructed PSFs at monochromatic X-ray energies of 15 to 63 keV, and compare them with
the PSFs computed from post-campaign metrology data, self-consistently treating profile and roughness data by means
of a method based on the Fresnel diffraction theory. The modeling matches the measured PSFs accurately.
The New Hard X-ray Mission (NHXM) is a space X-ray telescope project focused on the 0.2 to 80 keV energy band,
coupled to good imaging, spectroscopic and polarimetry detectors. The mission is currently undergoing the Phase B
study and it has been proposed to ESA as a small-size mission to be further studied in the context of the M3 call; even if
the mission was not downselected for this call, its study is being continued by ASI. The required performance is reached
with a focal length of 10 m and with four mirror modules, each of them composed of 70 NiCo electroformed mirror
shells. The reflecting coating is a broadband graded multilayer film, and the focal plane is mounted onto an extensible
bench. Three of the four modules are equipped with a camera made of two detectors positioned in series, a Silicon low
energy detector covering the range 0.2 to 15 keV and a high energy detector based on CdTe sensitive from 10 keV up to
120 keV. The fourth module is dedicated to the polarimetry to be performed with enhanced imaging capabilities. In this
paper the latest development in the design and manufacturing of the optics is presented. The design has been optimized
in order to increase as much as possible the effective area in the high-energy band. The manufacturing of the mirror
shells benefits from the latest development in the mandrel production (figuring and polishing), in the multilayer
deposition and in the integration improvements.
MPE will provide the X-ray Survey Telescope eROSITA for the Russian Spektrum-Roentgen-Gamma Mission to be
launched in 2013. It consists of a compact bundle of 7 co-aligned mirror modules with a focal length of 1600 mm and 54
nested mirror shells each. Therefore, its sensitivity in terms of effective area, field-of-view (61'), and angular resolution
(15" HEW on-axis) will yield a high grasp of about 1000 cm2 deg2 around 1 keV with an average angular resolution of
~26" HEW over the field-of-view (30" including optical and spacecraft error contributions). After an extended test
program on single mirror shells, assembled test modules (6 shells) and a qualification model we have now started
integration of flight mirror modules. We give a résumé on the development and test program including key
improvements to the shell integration method. Moreover, we report on the integration progress and present first results
on the X-ray performance of partially integrated mirror modules.
Focusing mirrors manufactured via a galvanic replication process from negative shape mandrels is the chosen solution
for the eROSITA X-ray mission. Media Lario Technologies (MLT) is the industrial enabler for manufacturing (in
collaboration with the Max Planck Institute (MPE) and the German Space Agency (DLR)) of the Optical Payload for
eROSITA - including the flight quality mandrels. Mandrels manufacturing holds a crucial role in the process of
fabrication of the optics. In fact, the shape accuracy and the roughness of the replicated mirrors are strongly affected by
the starting quality of the mandrel. For the e-ROSITA mandrel production an evolution of the approach used for the
manufacturing of past mission mandrels (JET-X, XMM) have been developed. The low energy angular resolution of the
eROSITA mirror payload needs to be 15 arcsec HEW or better; and at 8.05keV the angular resolution needs to be 20
arcsec HEW or better. Replicated mirrors with performance in this range for the low energy radiation have been
obtained in the past by using mandrels that have superior geometrical shape accuracy. A proprietary multistep surface
finishing process has now been developed for reaching the aggressive performance requirements demanded by the
mission. The status and the metrology of the eROSITA series mandrels manufactured so far, by using the
advanced polishing process, are presented. In the paper, the x-ray performance of mirror shells (as measured at MPE
PANTER facility) replicated from a flight quality eROSITA mandrel, are reported.
In the frame of the technology development to be used for the Optical Payload of next future X-ray missions (such as
e.g. New Hard X-ray Mission-ASI), a new set of manufacturing techniques were finalized by Media Lario Technologies
(MLT), in collaboration with the Italian Space Agency (ASI) and the Brera Astronomical Observatory (INAF/OAB).
The set of new technologies includes master manufacturing machines and processes, electroforming method, a vertical
optical bench and metrology machines to support manufacturing and integration of mirrors. A magnetron sputtering
PVD machine was upgraded and a Pt/C development study has been performed on the basis of the W/Si results obtained
in the first phase of the study.
New manufacturing technologies for highly accurate masters were developed and tested by mean of two full-size
masters together with several dummies. A number of ultrathin Nickel-Cobalt focusing mirrors were manufactured via
galvanic replication process from the masters and coated with Pt/C multilayer. Tests on substrate material, roughness
and shape of the shell together with analysis on specimens were performed. Tests with AFM and XRR supported the
development of the Pt/C multilayer which is the enabling technology for focusing high energy X-Rays.
Several mirror shells were integrated into two demonstrator modules to assess the whole manufacturing process up to
optical payload integration. The summary of the results from manufacturing and testing of specimens and mirror shells
is reported in this paper together with a description of the technologies now available at MLT.
Focusing mirrors manufactured via galvanic replication process from negative shape mandrels is the candidate solution
for some of next future X-ray missions. Media Lario Technologies (MLT) is the industrial enabler developing, in
collaboration with Brera Astronomical Observatory (INAF/OAB) and Italian Space Agency, the Optical Payload for the
New Hard X-ray Mission (NHXM) Italian project. The current and ongoing development activities in Media Lario
Technologies complement the electroforming technology with a suite of critical manufacturing and assembly of the
Mirror Module Unit. In this paper, the progress on mandrels manufacturing, mirror shell replication, multilayer coating
deposition and mirror module integration, leading to the manufacturing and testing of some astronomical Hard X-ray
Engineering Models, is reported. Mandrel production is a key point in terms of performances and schedule; the results
from mandrels fabricated using a proprietary multistep surface finishing process are reported. The progress in the
replication of ultrathin Nickel and Nickel-Cobalt substrates gold coated mirror shells is reported together with the results
of MLT Magnetron Sputtering multilayer coating technology for the hard x-ray waveband and its application to Pt/C.
Mandrel replication by NiCo electroforming is an upgrade of the well-suited X-ray mirrors manufacturing process with
pure Nickel. In this process, a Gold layer deposited on the mandrel acts as release agent and, at the same time, as
reflective coating. To increase the optical performances of X-ray mirrors, the replicated optical surface is meant to
reproduce the smooth topography of the mandrel: a surface degradation is commonly observed, indeed. A factor leading
to surface smoothness worsening can be the spontaneous roughness growth of the Gold layer itself; therefore, the optical
quality of the reflecting surface might be improved by optimizing the Gold layer thickness. A preliminary study, aimed
at investigating the effects of Gold thickness reduction (< 100 nm Vs. the usual 200 nm), had already been dealt in the
spectral range 0.02-1000 μm: measurements performed on flat electroformed samples showed that the Gold thickness
reduction chiefly affects the roughness around 1 μm. Here we presents a study of the effectiveness of a Gold layer with
reduced (< 100 nm) thickness in the NiCo X-ray mirrors electroforming, aimed at surface micro-roughness mitigation.
The characterization, in the spectral range 0.02-1000 μm, of 3 X-ray mirrors manufactured utilizing Gold layers with
different thickness values from a flight mandrel is reported. The performed investigation is organized as follows: (a)
characterization of the flight mandrel; (b) dependence of the micro-roughness from different Gold layers thicknesses
supported by XRD study; (c) comparison of the micro-roughness of mirrors manufactured in NiCo in Ni, with the same
Gold layer thickness. As a conclusive remark the effects of the Gold layer thinning on the angular degradation at high
energy are reported.
The New Hard X-ray Mission (NHXM) project will be operated by 2016 and is currently undergoing the Phase B study.
It is based on 4 hard X-ray optics modules, each formed by 60 evenly spaced multilayer coated Wolter I mirror shells.
An extensible bench is used to reach the 10 m focal length. The Wolter I monolithic substrates with multilayer coating
are produced in NiCo by electroforming replication. Three of the mirror modules will host in the focal plane a hybrid a
detector system (a soft X-ray Si DEPFET array plus a high energy CdTe detector). The detector of the fourth telescope
will be a photoelectric polarimeter with imaging capabilities, operating from 2 up to 35 keV. The total on axis effective
area of the three telescopes at 1 keV and 30 kev is of 1500 cm2 and 350 cm2 respectively, with an angular resolution of
20 arcsec HEW at 30 keV. In this paper we report on the design and development of the multilayer optics of the mission,
based on thin replicated Ni mirror shells.
High throughput lightweight Hard X-ray Optics manufactured via electroforming replication process from supersmooth
mandrels are the primary candidate for some of future New Hard X-ray missions. Media Lario Technologies (MLT) is
the industrial enabler exploiting the electroforming technology initially applied for the ESA XMM-Newton mission and
further developed in cooperation with Brera Astronomical Observatory (INAF/OAB). The current and ongoing
development activities in Media Lario Technologies complement the electroforming technology with a suite of critical
manufacturing and assembly of the Mirror Module Unit. In this paper, the progress on mandrels manufacturing, mirror
shell replication, multilayer coating deposition, mirror module integration, and relevant metrology is reported in view of
the upcoming production phase. Mandrel production is a key point in terms of performances and schedule; the results
from of NiP prototype mandrels fabricated using a proprietary multistep surface finishing process are reported. The
progress in the replication of ultrathin Nickel and Nickel-Cobalt substrates gold coated mirror shells is reported together
with the results of MLT Magnetron Sputtering multilayer coating technology for the hard x-ray waveband and its
application to W/Si. Due to the criticality of low thickness mirror handling, the integration concept has been refined and
tested on prototype mechanical structures under full illumination UV vertical optical bench.
The New Hard X-ray Mission (NHXM) Italian project will be operated by 2016. It is based on 4 hard X-ray optics
modules, each formed by 60 evenly spaced multilayer coated Wolter I mirror shells. For the achievement of a long focal
length (10 m) an extensible bench is used. The pseudo-cylindrical Wolter I monolithic substrates where the multilayer
coating is applied will be produced using the Ni electroforming replica approach. For three of the four mirror modules
the focal plane will host a hybrid a detector system, consisting in the combination of a Si-based low energy detector
(efficient from 0.5 up to ~ 15 keV) , on top of a high energy CdTe pixellated detector (efficient from 10 keV up to ~ 80
keV); the two cameras will be surrounded by both a passive shield and an anticoincidence shield. The total on axis
effective area of the three telescopes at 1 keV and at 30 kev is of 1500 cm2 and 350 cm2 respectively. The angular
resolution requirement is better than 20 arcsec HEW at 30 keV, while the Field of View at 50% vignetting is 12 arcmin
(diameter). The payload is finally completed with the fourth telescope module, that will have as a focal plane detector a
high sensitivity imaging photoelectric polarimetric system, operating from 2 up to 35 keV. In this paper, after an
overview of the mission configuration and its scientific goals, we report on the design and development of the multilayer
optics of the mission, based on thin replicated Ni mirror shells.
Focusing mirrors manufactured via galvanic replication process from negative shape mandrels is the candidate solution
for some of next future X-ray missions. Media Lario Technologies (MLT) is the industrial enabler developing, in
collaboration with Brera Astronomical Observatory (INAF/OAB), the Optical Payload for future Hard X-ray mission.
Concerning mandrel technology, MLT is engaged in a development programme aiming at improving the mandrels
performance and their production rate. The angular resolution and the reflectivity of the mirrors replicated from the
mandrels are strongly dependent on the mandrel performances and their stability. High throughput X-ray missions,
require the massive production of mandrels in a short time, with angular resolution better than 7 arcsec Half Energy
Width (HEW) and a surface micro-roughness in the order of 0.3 nm RMS. In order to achieve these results, several
technological aspects are under investigation using a proprietary multistep surface finishing process. In particular, the
metrology and the estimated optical performances of the mandrel are computed by means of dedicated post-processing
and herein reported. Microroughness, medium scale errors, azimuthal slope error, axial slope errors, and mechanical
dimensions are the quantities that have been measured by using atomic force microscope, high resolution optical
profiler, contactless rotondimeter and high accuracy axial profilometer.
MPE will provide the X-ray Survey Telescope eROSITA [5] for the Russian Spektrum-Roentgen-Gamma Mission [4] to
be launched in 2011. The design of the X-ray mirror system is based on that of ABRIXAS: The bundle of 7 mirror
modules with the short focal length of 1600 mm makes it still a compact instrument while, however, its sensitivity in
terms of effective area, field-of-view, and angular resolution shall be largely enhanced with respect to ABRIXAS. The
number of nested mirror shells increases from 27 to 54 compared to ABRIXAS thus enhancing the effective area in the
soft band by a factor of six. The angular resolution is targeted to be 15 arc seconds half-energy width (HEW) on-axis
resulting in an average HEW of 26 arc seconds over the 61 arc minutes field-of-view (FoV). The instrument's high grasp
of about 1000 cm2deg2 in the soft spectral range and still 10 cm2deg2 at 10 keV combined with a survey duration of 4
years will generate a new rich database of X-ray sources over the whole sky. As the 7 mirror modules are co-aligned
eROSITA is also able to perform pointed observations.
The SIMBOL-X formation-flight X-ray mission will be operated by ASI and CNES in 2014, with a large participation of
the French and Italian high energy astrophysics scientific community. Also German and US Institutions are contributing
in the implementation of the scientific payload. Thanks to the formation-flight architecture, it will be possible to operate
a long (20 m) focal length grazing incidence mirror module, formed by 100 confocal multilayer-coated Wolter I shells.
This system will allow us to focus X-rays over a very broad energy band, from 0.5 keV up to 80 keV and beyond, with
more than two orders of magnitude improvement in angular resolution (20 arcsec HEW) and sensitivity (0.5 µCrab on
axis @30 keV) compared to non focusing detectors used so far. The X-ray mirrors will be realized by Ni
electroforming replication, already successfully used for BeppoSAX, XMM-Newton, and JET-X/SWIFT; the
thickness trend will be about two times less than for XMM, in order to save mass. Multilayer reflecting coatings
will be implemented, in order to improve the reflectivity beyond 10 keV and to increase the field of view 812
arcmin at 30 keV). In this paper, the SIMBOL-X optics design, technology and implementation challenges will be
discussed; it will be also reported on recent results obtained in the context of the SIMBOL-X optics development
activities.
We consider a mobile robot that attempts to accomplish a task by reaching a given goal, and interacts with its environment through a finite set of actions and observations. The interaction between robot and environment is modeled by Partially Observable Markov Decision Processes (POMDP). The robot takes its decisions in presence of uncertainty about the current state, by maximizing its reward gained during interactions with the environment. It is able to self-locate into the environment by collecting actions and perception histories during the navigation. To make the state estimation more reliable, we introduce an additional information in the model without adding new states and without discretizing the considered measures. Thus, we associate to the state transition probabilities also a continuous metric given through the mean and the variance of some significant sensor measurements suitable to be kept under continuous form, such as odometric measurements, showing that also such unreliable data can supply a great deal of information to the robot. The overall control system of the robot is structured as a two-levels layered architecture, where the low level implements several collision avoidance algorithms, while the upper level takes care of the navigation problem. In this paper, we concentrate on how to use POMDP models at the upper level.
For the CASSINI mission, Officine Galileo are presently developing, under Jet Propulsion Laboratory (JPL) contract, a CCD based star tracker, named Stellar Reference Unit (SRU). The SRU will be used in a new attitude determination approach developed by JPL, in which 'gyroless' operation can be implemented. The unit has a wide angle (15 degree(s) full cone) Field of View (FOV) and a maximum sensitivity up to +6 Visual Magnitude for an integration time of 400 msec. Exposure time can be commanded via Attitude and Articulation Control Subsystem Flight Computer (AFC) from 0 to 65535 msec. Optics characteristics and centroiding algorithm for star position determination, are defined by Officine Galileo, to achieve required performance (total accuracy: 53 (mu) rad, 3(sigma) ). The defined centroiding algorithm will be then implemented on the AFC. In this paper, the SRU architecture, characteristics, and main technological areas are described. Expected performance is reported.
The Cassini spacecraft will perform a detailed examination of the Saturnian system, including the release of a probe to study Saturn's largest satellite, Titan. The star tracker for the Cassini mission must provide accurate data during the entire flight including four years of measurement in a harsh radiation environment. The star tracker will provide autonomous star identification over the entire celestial sphere using a 4,000 entry on-board star catalog. Three axis attitude reference will be determined by measurements of two to five stars in the tracker field of view which will allow the gyroscopes to be powered off during the cruise phase of the flight. When the gyros are operational, attitude updates will be provided. The Cassini star tracker consists of a CCD based star camera, called the stellar reference unit (SRU), which is being designed and built by Officine Galileo. The operation of the SRU, including functional modes, exposure times, and areas of the CCD to digitize is under the control of the Cassini Attitude and articulation control subsystem (AACS) flight computer (AFC). The raw digital pixel data is transmitted from the SRU through a dedicated direct memory access (DMA) interface to the AFC memory for subsequent processing. All pixel processing and centroiding is performed within the AFC. Once the initial attitude has been determined, the AFC algorithms will choose which stars within the SRU field of view to track in order to maintain attitude knowledge. The SRU will have a 15 degree field of view and will provide 60 (mu) rad (3 (sigma) ) 2-axis position measurement accuracy for stars of approximately 6.05 visual magnitude and brighter. The required 1 mrad (3 (sigma) ) twist accuracy is provided by star separation.
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