The key mission objective of the Solar Orbiter is to study the Sun from close-up (45 solar radii, or 0.21 AU) in an orbit tuned to solar rotation in order to examine the solar surface and the space above from a co-rotating vantage point at high spatial resolution. Solar Orbiter will also provide images of the Sun's polar regions from heliographic latitudes as high as 38 degrees. The strawman payload encompasses two instrument packages: Solar remote-sensing instruments: EUV full-sun and high resolution imager, high-resolution EUV spectrometer, high-resolution and full-sun visible light telescope and magnetograph, EUV and visible-light coronagraphs, radiometers. Heliospheric instruments: solar wind analyzer, radio and plasma wave analyzer, magnetometer, energetic particle detectors, interplanetary dust detector, neutral particle detector, solar neutron detector. To reach its novel orbit, Solar Orbiter will make use of low-thrust solar electric propulsion (SEP) interleaved by Earth and Venus gravity assists. Solar Orbiter was selected by ESA's Science Programme Committee (SPC) in October 2000 as a Flexi-mission, to be implemented after the BepiColombo cornerstone mission to Mercury before 2013. This paper summarizes the science to be addressed with the Solar Orbiter, followed by brief descriptions of the strawman payload, the mission profile, and the spacecraft and ground segment designs.

The Ultraviolet and Visible-light Coronagraph Imager (UVCI) proposed for the European Space Agency (ESA) Solar Orbiter mission, is designed to image the visible and the ultraviolet coronal emissions, in order to diagnose the solar corona. The UVCI is an externally occulted reflection coronagraph that obtains monochromatic images in the neutral hydrogen HI 121.6 nm and in the single ionized helium HeII 30.4 nm lines, and measures the polarized brightness (pB) of the K-corona in broadband visible light. One of the most stringent requirements in the design of a coronagraph is the stray light rejection. The stray light is produced by solar disk radiation which is several order of magnitude brighter than the coronal radiation in both visible and UV. The solar disk radiation enters the instrument through the external aperture and stray light is produced by diffraction off the edges of the apertures and of the optical components, non-specular reflections off the mirror surfaces, and scattering off the mechanical structure. In this paper, the features in the optical design that contribute to the stray light reduction are described, and an analysis of all possible stray light contributions is performed on the optical configuration of the UVCI sounding rocket prototype (UVC-SR). From this analysis, a stray light model has been developed and its results are compared with the minimum measurable signal expected from the solar corona.

The optical design of a stigmatic grazing-incidence telescope-spectrometer for solar imaging spectroscopy is presented. The instrument is designed for the Solar Orbiter mission. It consists of a double telescope and a flat-field spectrometer. The telescope 1 is a single-element telescope: it focuses the radiation on the entrance slit of the spectrometer only in the direction perpendicular to the slit, i.e. the spectral dispersion plane. The telescope 2 is a double-element Wolter telescope: it focuses the radiation on the focal plane in the direction parallel to the slit, i.e. perpendicular to the spectral dispersion plane. Finally, the spectrometer consists of a grazing-incidence variable-line-spaced grating with flat-field properties. The telescope 2 is crossed with respect to the telescope 1 and the grating, i.e. it is mounted with its tangential plane coincident with the grating equatorial plane. The spectrum is acquired by a detector at near normal incidence with respect to the direction of the exit beam. Such unique configuration gives stigmatic monochromatic images of extended regions even in the grazing-incidence domain.

Two configurations with multilayer-coated optics for an EUV and soft X-ray telescope-spectrometer for imaging spectroscopy on the Solar Orbiter mission are presented. The telescope is designed with conventional grazing-incidence optics, in order to reduce the thermal load on optics looking directly at the solar disk. The spectrometer mounts a normal-incidence multilayer-coated grating, being protected by the entrance slit. Two configurations are presented: a grazing-incidence telescope that feeds a normal-incidence grating spectrometer and two grazing-incidence telescopes with cylindrical mirrors in the Kirkpatrick-Baez configuration and a normal-incidence spectrometer with a cylindrical grating. In the former case, the off-axis resolution of the telescope is degraded by the grating aberrations. In the latter case, the spectral and spatial focusing properties are fully uncoupled: the off-axis resolution is independent from the grating performance. The performance in the 18-22 nm spectral region are compared with those of a grazing-incidence telescope-spectrometer.

The Heliospheric Imager (HI) is part of the SECCHI suite of instruments on-board the two STEREO spacecrafts to be launched in 2005. The two HI instruments will provide stereographic image pairs of solar coronal plasma and address the observational problem of very faint coronal mass ejections (CME) over a wide field of view (~90 degree(s)) ranging from 13 to 330 R₀. The key element of the instrument design is to reject the solar disk light, with straylight attenuation of the order of 10^-13 to 10^-15 in the camera systems. This attenuation is accomplished by a specific design of straylight baffling system, and two separate observing cameras with complimentary FOV's cover the wide FOV. A multi-vane diffractive system has been theoretically optimized to achieve the lower requirement (10^-13 for HI-1) and is combined with a secondary baffling system to reach the 10^-15 rejection performance in the second camera system (HI-2). This paper presents the design concept of the HI optics and baffles, and the preparation of verification tests that will demonstrate the instrument straylight performances. The baffle design has been optimized according to accommodation constrains on the spacecraft, and the optics were studied to provide adequate light gathering power and image quality. Straylight has been studied in the complete configuration, including the lens barrels and the focal plane assemblies. A specific testing facility is currently being studied to characterize the effective straylight rejection of the HI baffling. An overview of the developments for those tests is presented.

As a Japanese National space mission with international collaboration, Solar-B (2005 launch) will carry a spectro- polarimeter (SP) to be operated in visible light to obtain the first high angular resolution, precision measurements of solar vector magnetic fields from space. The SP is part of the Focal Plane Package (FPP) fed by a diffraction-limited 50-cm optical telescope. The SP will be operated exclusively at the photospheric 630 nm Fe I lines. It features a rotating, low-order crystalline quartz retarder for polarization modulation and a reflecting Littrow spectrograph design that is shortened by using diffraction from the 12micrometers wide slit to fill the grating. Polarization analysis is accomplished by a modified Savart plate beam splitter. A custom CCD detector with two active areas, one for each beam from the beam splitter, allows continuous high duty-cycle sampling of polarization. The spectrograph slit will sample a 0.16 x 164 arcsec² rectangle of the solar image, which may be scanned across the slit by up to +/- 160 arcsec in order to build up vector magnetic field maps of the solar photosphere. Along with simultaneous, co-spatial imaging and polarimetry with the filter imagers of the FPP, the SP will provide a precise view of active and quiet solar magnetic fields that control the structure, dynamics, and energetics of the upper solar atmosphere.

The Solar Mass Ejection Imager (SMEI) is a proof-of-concept space experiment designed to observe solar coronal mass ejections (CMEs) and forecast their arrival at Earth. SMEI will image CMEs by sensing sunlight scattered from the free electrons in these ejecta (i.e., Thomson scattering). SMEI will be launched by a Titan II rocket into a circular, 830-km, sun-synchronous orbit in mid-2002 as part of the Space Test Program's CORIOLIS mission. SMEI will image nearly the entire sky once per spacecraft orbit over a mission lifetime of three years. Successful operation of SMEI will represent a major step in improving space weather forecasts by providing one- to three-day predictions of geomagnetic storms at the Earth. The SMEI experiment is being designed and constructed by a team of scientists and engineers from the Air Force Research Laboratory, the University of Birmingham (UB) in the United Kingdom, the University of California at San Diego (UCSD), and Boston University. The Air Force, NASA, and UB are providing financial support.

The Solar EUV Experiment (SEE) on the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite will make measurements of the spectral irradiance of the Sun in the soft x-ray, extreme ultraviolet (EUV), and far ultraviolet (FUV) wavelength range. The EUV Grating Spectrograph (EGS) component of SEE is a 1/4 meter Rowland circle spectrograph with a mechanically-ruled concave grating and a microchannel plate detector with a two-dimensional 1024 x 64 coded anode (CODACON) readout. The EGS covers the wavelength range from approximately 26 to 197 nm. The primary calibration of the instrument was done at the NIST Synchrotron Ultraviolet Radiation Facility (SURF) III on their beam line #2. We will detail the calibration methods and results for the EGS, paying attention to the quantification of sensitivity variations over the instrument's large field of view (12.5 degree(s) x 5.3 degree(s)), plus scattered light, second-order, and linearity corrections.

This paper will describe the scientific objectives of the Marshall Space Flight Center (MSFC) Solar Ultraviolet Magnetograph Investigation (SUMI) and the optical components that have been developed to meet those objectives. In order to test the scientific feasibility of measuring magnetic fields in the UV, a sounding rocket payload is being developed. This paper will discuss: (1) the scientific measurements that will be made by the SUMI sounding rocket program, (2) how the optics have been optimized for simultaneous measurements of two magnetic lines CIV (1550 Angstroms) and MgII (2800 Angstroms), and (3) the optical, reflectance, transmission and polarization measurements that have been made on the SUMI telescope mirrors and polarimeter.

A four-mirror optic has been derived from a previous three- mirror system, with characteristics that have significant advantages for imaging in the EUV. The compact format enables the total length to be less than the entrance pupil diameter; the focal surface is flat and with rear access; the aperture stop is located coplanar with the secondary, thus ensuring that bignetting is zero and that the pupil is identical at all field angles. Stray light baffling is 100% when the optic is fully enclosed. The aberration correction is good enough for diffraction- limited imaging over most of a 1 degree(s) field angle at wavelengths down to 50nm for a typical 1m entrance pupil diameter. The speed of the 1m pupil diameter example system is f/2.4, but trade-off can be made with other characteristics to achieve faster or slower systems. An f/1.2 system has been designed as an exercise. For all derived systems, scaling is possible to much larger pupil diameters by sacrificing field angle. Realization of the most complex design would require significantly advanced optical fabrication technology. All four surfaces are aspheric, the convex secondary being the only pure hyperboloid. The primary and tertiary can be fabricated on a single substrate. The quaternary mirror is in the form of a zone plate. The performance data for this design show that 90% enclosed energy does not exceed 1 micrometers diameter at all field angles up to 0.4 degree(s) off-axis. Simplified designs are possible for imager devices with larger pixels. For a given pupil diameter, [mass x volume to orbit]-related costs would be unusually favorable.

The flight microchannel plate detectors to be used in the Cosmic Origins Spectrograph, a fourth generation instrument for the Hubble Space Telescope, have been calibrated in the laboratory before being integrated into the spectrograph. This paper presents the results of these calibrations that include measurements of the detector quantum efficiency, spatial resolution, spatial linearity, flat field, electronic livetime and the local count rate limit.

SD2000 is a new photon counting MCP based detector. It consists of a single MCP, coated with a suitable photocathode, closely coupled to a Silicon Drift Detector (SDD). The electron clouds generated by the MCP channels are accelerated by a strong electric field applied and proximity focussed on the SDD, that works as a position sensitive read-out detector. The SDD, developed by the INFN laboratories in Trieste, is a butterfly Silicon Drift Detector with no metal deposition on its cathodes. The absence of metallization in the sensitive zone of the chamber allows the electron clouds to penetrate uniformly into the active region of the detector and to be revealed. A suitable front-end amplifier, that works as a charge preamplifier and a bipolar shaper, has been developed starting from SPICE simulations and tested. A proto-type of the detector has been realized and tested and the first results have been achieved and compared with the expected best performances of the detector.

A progress report on the work, started ten months ago, aimed to evaluate the use of a new type of position sensor (Complementary Metal Oxide Semiconductor Active Pixel Sensor or CMOS-APS) as readout system in MCP-based intensified photon counting systems, is presented in this paper. The main differences respect to the more classical Photon Counting Intensified CCDs (PC-ICCD), the advantages and the disadvantages of their use as image photon counters, the adopted solutions to acquire the images and compute the photon event center, are described. The adopted optics and the designed mechanical assembly are also shown. The selected CMOS-APS, heart of the system, is treated in detail, as well as the electronics designed to drive the detector, to compute the center of the luminous spot on the MCP phosphor screen, and to send and receive data from a host computer. Finally we present preliminary results and achieved performances.

We report about preliminary results of the characterization of a new kind of MCP-based detector: a Photon Counting Intensified Active Pixel Sensor (APS). PC-IAPS appears as the natural evolution of the Intensified CCD, maintaining the basic characteristics, but with improved performance in terms of dynamic range, along with some other appealing properties: higher radiation hardness, more compact design, lower requirements on the external electronics, low power consumption. The prototype we realized is currently in an early stage of development. Nevertheless, it allows us to demonstrate the feasibility of the photon counter and to measure some of the basic parameters. Some of the characteristics of the APS, relevant to the use in intensified systems, are analyzed and compared with the CCD ones, demonstrating the potentiality of the new device and allowing us to set the basis of future development.

This paper addresses the imager designs for an upcoming NASA mission to examine comets at distances from the sun fairly similar to that of the earth. The general constraints on design typical to a small spacecraft such as low mass and operation in vacuum apply. In addition the transient nature of the data which are presented as spacecraft moves by the comet at high speed must be considered. Two imagers with different tasks to perform will be flown on this mission. Design choices for electronics and selection of charge coupled device image sensors are discussed. Some early results from breadboard tests are presented.

We present here comprehensive experimental data corresponding to helium extreme ultraviolet emission (EUV) for the 300-600A wavelength range in e^- + He, H⁺ + He, and Hn_n⁺ + He (n=2-3) collisions with impact velocities ranging from 1.4 to 6.9 a.u. The degree of linear polarization associated with HeI (1snp) ¹P^o -> (1s²) ¹S decays for n-2-5 ((lambda) =510 to 584A) and HeII (2p) ²P^o -> (1s) ²S transitions ((lambda) =304A), have been measured at intermediate and higher energies. These measurements have been conducted using a compact lightweight molybdenum/silicon multilayer mirror (MLM) spetropolarimeter. These experimental results are compared with our most advanced theoretical calculations using the close coupling method and several many body perturbation approaches. In this study, the degree of linear polarization will be discussed as a function of the projectile charge to elucidate few body excitation and ionization-excitation processes. Specifically, more sophisticated calculations including second Born approximation with full off-energy terms for the HeII (2p) ²P^o sublevels have been used. The excellent agreement with our HeII Lyman-(alpha) data clearly demonstrates that off-energy terms in two-electron atomic interaction have very prominent effects. Our comprehensive experimental and theoretical database is also of great importance for the understanding of solar physics phenomena. Such results can be used as a new diagnostic tool for clarifying the role of electron and proton beams in solar flares.

The Cosmic Origins Spectrograph (COS) is a new instrument for the Hubble Space Telescope that will be installed during servicing mission 4, currently scheduled for January 2004. The primary science objectives of the mission are the study of the origins of large scale structure in the universe, the formation, and evolution of galaxies, the origin of stellar and planetary systems and the cold interstellar medium. As such, COS has been designed for the highest possible sensitivity on point sources, while maintaining moderate ((lambda) /(Delta) (lambda) =20,000) spectral resolution. In this paper, the instrument design and predicted performance is summarized, as well as summary of the instrument flight and prototype component performance to date.

We describe the design, scientific objectives, and radiometric performance and calibration results of the Rosetta/ALICE instrument. ALICE is a lightweight (3.0 kg), low-power (4 W), low-cost imaging spectrometer optimized for cometary ultraviolet spectroscopy. Funded by NASA (with hardware contributions from CNES, France), ALICE will fly in 2003 on the ESA Rosetta Orbiter to characterize the cometary nucleus, coma, and nucleus/coma coupling of the Rosetta mission prime target comet 46P/Wirtanen. ALICE will also make observations of two asteroid flyby targets and of the Moon and Mars during the cruise portions of the Rosetta mission. It will obtain spatially-resolved, far-UV spectra of Wirtanen's nucleus and coma in the 700-2050A passband with a spectral resolution of 8-12A for extended sources that fill the entrance slit's 0.05 degree(s) x 6 degree(s) field-of-view. An improved derivative of the Rosetta/ALICE is also the UV spectrometer aboard the PERSI remote sensing suite proposed for the Pluto Kuiper Belt mission. ALICE uses modern technology to achieve its low mass and low power design specifications. It employs an off-axis telescope feeding a 0.15-m normal incidence Rowland circle spectrograph with a concave (toroidal) holographic reflection grating. The imaging microchannel plate (MCP) detector utilizes dual solar-blind opaque photocathodes of KBr and CsI deposited on a cylindrically-curved (7.5-cm radius) MCP Z-stack, and a matching 2-D cylindrically-curved double delay-line readout array with a 1024 x 32 pixel array format. Three data taking modes exist: (i) histogram image mode for 2-D images, (ii) pixel list mode with periodic time fiducials for temporal studies, and (iii) count rate mode for broadband photometric studies. Optical and radiometric sensitivity performance results based on integrated system level tests of the ALICE flight model are presented and discussed.

This report describes the preliminary experimental results obtained by the analysis of the optical performance of the Qualification Model of the Wide Angle Camera for the Rosetta mission. This camera is an F/5.6 all-reflecting telescope with a rather large 12 degree(s) X 12 degree(s) field of view that satisfies the scientific requirements about spatial resolution, contrast capability, and spectral coverage, thanks to an original two-mirror, off-axis and unobstructed optical design. Theoretically, from the simulation with a ray-tracing code, more than 80% of the collimated beam energy falls within a single pixel (20' X 20') over the whole camera field of view, and the possible contrast ratio is smaller than 1/1000. The analysis of the optical performance of the Qualification Model shows a good agreement between theoretical performance and experimental results. It's worth mentioning that this optical design is rather simple from a mechanical point of view, compact and relatively easy to be aligned. All these characteristics make this type of camera rather flexible and suitable also for other possible space missions in which similar performance are required.

A light photon-counting scientific payload, named AURORA, has been developed and launched on a commercial microsatellite in order to study the near-UV night-sky background emission (channel Notte) and the Aurora (Alba). AURORA is mapping, with the Notte channel, the night-side photon background in the 300-400 nm spectral range, together with a particular 2⁺ nitrogen line ((lambda) = 337nm). These measurements are required in the framework of the Extreme Universe Space Observatory (EUSO) experiment, approved by the European Space Agency (ESA) for the phase A and to be flown on the International Space Station (ISS) in 2009. The Alba channel studies the Aurora emissions in four different spectral bands centered on: 367nm, 391nm, 535nm, 560nm (OI). The instrument has been integrated on the MEGSAT-1 satellite and launched, on the September, 26th 2000, from the Baikonur cosmodrome. The nearly circular Low Earth Orbit (LEO), with inclination of 64.56 degrees, fully includes the ISS ground track envelope. The satellite overall mass is about 60 kg. An overview of the techniques adopted, including detectors, front-end electronics, Central Processor Unit (CPU), is given in this paper, together with a brief report on the mission status and plans.

We present a new instrument for narrow band imaging without the use of conventional interference filters. This instrument will image the OVI doublet at 103.2 and 103.8 nm, the brightest astrophysical emission line from diffuse gas at 300,000 degrees. Gases at this temperature, formed mostly by supernovae blast waves, are key to understanding the energy budget of the galaxy. To date, there are no high spatial resolution narrow-band images of OVI, although some low spatial resolution narrow maps have been acquired with conventional spectrographs. Using the imaging power of a conventional two-optic Gregorian telescope in conjunction with aberration-corrected holography, we can acquire narrow band images with subarcsecond spatial resolution. An aberration-corrected holographically ruled grating in place of the secondary optic is used to diffract the ultraviolet light to stigmatic focus. Additionally, the use of few optical surfaces minimizes the light loss from poor reflectivity of materials in the far ultraviolet (FUV), thereby maximizing instrument sensitivity. This instrument is the first to use aberration-corrected holographic gratings to produce a narrow-band imaging capability in this fashion. We are now developing a rocket payload to demonstrate the power of this technique with particular application to non-radiative shocks in the interstellar medium. We present the optical design, instrument performance, and relevant scientific simulations.

This paper discusses the scientific motivation for, design of and buildup of the Spatial heterodyne Spectrometer (SHS) for a sounding rocket mission to study the Cygnus Loop, a prototypical middle-ages supernova remnant. The results of that mission are also presented. The goal of the flight was to obtain a radial velocity-resolved spectrum of the C IV (lambda) 1550 emission line from the Cygnus Loop, as a test for doing the same from the diffuse hot interstellar medium (ISM). The reasons for wanting to look at the ISM this way are discussed, along with the properties of SHS. Important points about alignment (zero-path and zero-spatial-frequency setting), as well as shake testing and data analysis techniques (fringe correction, thermal drift tracking) are described. The SHS payload did not obtain a spectrum for th Cygnus Loop C IV emission line, because of reduced efficiency of the optical components. Results of post- flight efficiency tests to locate the source(s) of this loss are presented, showing contamination as the most likely problem. Ways to eliminate this contamination for future SHS sounding rocket and satellite missions conclude the presentation.

We describe a vacuum collimator that we have assembled to characterize the windowless ultraviolet properties of a sounding rocket spectrographic telescope. The collimator comprises a Cassegrain telescope, with SiC coated optics, used in the pre-flight calibration phase of the Far Ultraviolet Spectroscopic Explorer, and vacuum skins provided by NASA/Wallops. The collimator focal plane has a three-axis motorized stage, which we have used for the precision placement of a knife edge focal locator along with pinhole and flat-field sources. We describe the focusing procedure and present the results of a number of experiments whereby the collimator, telescope and spectrograph point spread functions were determined and a spectro-spatial flat-field of the detector was acquired.

We have fabricated the four flight gratings for a sounding rocket high-resolution spectrometer using a holographic ion-etching technique. The gratings are spherical (4000-mm radius of curvature), large (160 mm x 90 mm), and have a laminar groove profile of high density (3600 grooves/mm). They have been coated with a high-reflectance multilayer of Mo₅C/Si/Mo₂Si. Using an atomic force microscope, we examined the surface characteristics before and after multilayer coating. The average roughness is approximately 2-3A rms after coating, somewhat smoothened by the multilayer. Using synchrotron radiation, we completed an efficiency calibration map of each grating over the wavelength range 225-245A. At an angle of incidence of 5 degree(s) and a wavelength of 234A, the average efficiency peaks in the first inside order at 10.3+/- 0.6% for Grating 1, 7.3+/- 0.9% for Grating 6, 7.2+/- 1.2% for Grating 3, and 9.0+/- 1.5% for Grating 4. These values exceed all previously published results for a high density grating. The first order groove efficiency for Grating 1 is 34.4+/- 1.9%, in good agreement with the best value obtained from similar test gratings and close to the theoretical limit of 40.5%.

Rosetta is the cornerstone mission of ESA devoted to the study of minor bodies of Solar System. The mission will be launched on January 2003 and has the rendez-vous with P/Wirtanen comet (on November 2011) as primary target. The final aim of the mission will be a better understanding of the formation and composition of early Solar System and of its evolution over the last 4.5 billion years. Rosetta has a complex instrumentation devoted both to remote sensing and to in situ investigation. The authors were involved in the design and manufacturing of the Wide Angle Camera (WAC) of the OSIRIS imaging system. The WAC has a very peculiar optical system based on two aspherical mirrors in an off axis configuration, and will be principally devoted to the study of the very faint gas and dust cometary features. To reach this goal an innovative baffling system was designed and constructed in order to reach the stray-light suppression requirements both for source inside and outside the field of view of the camera. In particular a contrast ratio of 10^-4 inside the field of view is needed in order to detect gaseous and dusty features close to the nucleus of the comet. In this paper the process of baffling design and manufacturing is described: the behavior of the baffle, previously calculated by numerical simulations from the mechanical and optical points of view, was assessed both for the single elements and for the complete assembly as described in this paper.

The Solar Space Telescope (SST) is the largest scientific space project of China up to now. It engages to observe the transient and steady state solar hydrodynamic and magneto-hydrodynamic process over 2-D real time polarizing spectrum, UV, X-ray and H(alpha) image, and continuous time evolution with high spatial and temporal resolution in order to achieve a break through advance in solar physics. The EUV part of SST, the EUV telescope (EUT), consists of four telescopes with their detectors, which are parallel situated in a single telescope tube. Each telescope of the EUT adopts the normal-incidence principle with help of the multilayer technology and the primary mirror diameter is 12cm. The detectors of the EUT are constructed with EUV sensitive phosphors, fiber tapers, image intensifiers, CCDs, camera electronics and cooling blocks. Three telescopes of EUT are designed to achieve a spatial resolution of 0.5 arcsecond with a field of view (FOV) of 8.5'x8.5' in order to get the ever high-resolution image of the fine structure of the high temperature activities in solar corona and the fourth one is 85'x85' to have the full solar disk always in its field of view. In our presentation, the scientific objectives and the configuration of EUT are introduced.

A technical design of the OSIRIS two-based optical space interferometer is based on the carbon-fiber technology and on the newest Russian achievements in laser metrology and light sensors. The whole instrument was designed as a payload to the Russian Segment of the ISS and it consists of two blokes that will be brought to the ISS by transport spacecraft Progress and installed there by astronauts. Short-live devices of the OSIRIS interferometer - light sensor and metrological laser - are replaceable for fast repairs in the open space conditions. Due to the carbon- fiber strongly constructed case and to the absence of reserved devices the total mass of the OSIRIS interferometer will not exceed 250 kg. The two-based interferometer OSIRIS consists of four off-axis telescopes will have its own guide for precision pointing to the target stars. The whole instrument will use its own independent to the ISS pointing and tracking systems. It will be mounted to the RS ISS by magnetic controlled suspension device. The OSIRIS Project was admitted to the Russian National Space Program as a payload to the RS ISS at the promoted stage, and it might be launched at 2002-2003 years.

During the last decade, many studies have addressed the use of synthetic diamond as sensing material for deep UV photon detection. Solar missions, as the Solar Orbiter and the Solar Probe will require UV photon detectors with unprecedented sensitivity at wavelengths (lambda) <200 nm and radiation hardness. Diamond appears to be the ideal photosensitive material for such applications, as it is very solar blind (10⁵ rejection ratio (lambda) >230 nm and 10⁷ above 400 nm), its very low dark current level avoids the use of cooling systems, has a high UV responsivity and it is radiation hard and chemically inert. This paper is a review of our recent results on the electro- optical properties of diamond and a comparative analysis and characterization of the performances of different diamond- based photodetectors in the vacuum UV. In addition, we will describe some of the photodetectors that are under development for space applications and that will exploit the properties of diamond.

A new concept CCD camera is currently being realized at the XUV Lab of the Department of Astronomy and Space Science of the University of Florence. The main features we aim to get are a high level of versatility and a fast pixel rate. Within this project, a versatile CCD sequencer has been realized with interesting and innovative features. Based on a microcontroller and complex programmable logic devices (CPLD), it allows the selection of all the parameters related to charge transfer and CCD readout (number, duration and overlapping of serial and parallel transfer clocks, number of output nodes, pixel transfer rate) and therefore it allows the use of virtually any CCD sensor. Comparing to a common DSP-based sequencer, it is immune to jitter noise and it can also reach pixel rates greater than 40 MHz. The software interface is LabVIEW 6i based and it will allow both local or remote control and display. Furthermore, it will be possible to remote debug the system and to upgrade the LabVIEW interface itself and also the microcontroller resident program and the CPLD implemented schemes.

The cross strip anode is a coarse (o.5 mm) multi-layer metal and ceramic cross strip pattern. Event positions are encoded by direct sensing of the charge on each strip and subsequent determination of the charge cloud centroid for each event. This event position encoding is accomplished with chip preamplifiers on the anode, subsequent analog to digital conversion of individual strip charge values and a software centroid determination. The spatial resolution (<5micrometers ) achieved for an 8 x 8mm anode is sufficient to resolve 7micrometers microchannel plate pores while using low MCP gain (approximately equals x 10⁶) in an MCP pair configuration. The image linearity is good enough to enable distortions in the microchannel plate pore pattern to be seen as well as dead and distorted pores. The low MCP gain will enhance the local counting rate capacity and overall lifetime of a microchannel plate detector system with cross strip readout. We discuss plans for fabrication of a 32mm x 32mm anode with custom chip electronics so that encoding may be accomplished at photon counting rates >1 MHz and with low power consumption (~2W) suitable for applications in space astrophysics.

GSFC is in the process of assembling a solar EUV Normal-Incidence Spectrometer called EUNIS, to be flown as a sounding rocket payload. This instrument builds on the many technical innovations pioneered by our highly successful SERTS experiment over its past ten flights. The new design has improved spatial and spectral resolutions, as well as 100 times greater sensitivity, permitting EUV spectroscopy with a temporal resolution near 1 second for the first time ever. To achieve such high time cadence, a novel Active-Pixel-Sensor detector is being developed as a key component of our design. The high sensitivity of EUNIS allows entirely new studies of transient coronal phenomena, such as the rapid loop dynamics seen by TRACE, and searches for non-thermal motions indicative of magnetic reconnection or wave heating. The increased sensitivity also permits useful EUV spectra at heights of 2-3 solar radii above the limb, where the transition between the static corona and the solar wind might occur. In addition, the new design features two independent optical systems, more than doubling the spectral bandwidth covered on each flight. Its 300-370A bandpass includes He II 304A and strong lines from Fe XI-XVI, extending the current SERTS range of 300-355A to further improve our ongoing series of calibration under-flights for SOHO/CDS and EIT. The second bandpass of 170-205A has a sequence of very strong Fe IX-XIII lines, and allows under-flight support for two more channels on SOHO/EIT, two channels on TRACE, one on Solar-B/EIS, and all four channels on the STEREO/EUVI instrument. First flight of the new EUNIS payload is presently scheduled for 2002 October.

Time-delay anodes are typically used in conjunction with microchannel plates to provide photon counting and two- dimensional imaging. The anode and associated electronics are used to compute the centroid of the charge cloud from the microchannel plate stack. The computation is done in analog circuitry and reported as a digital value. The analog nature of the time-delay anode makes them susceptible to variations in the correlation between physical space and the reported digital value. These variations, both local and global, must be corrected as part of the data reduction of scientific data. If left uncorrected in spectral data, for example, these variations would result in inaccurate wavelength identifications and distorted spectral line profiles. This work describes successful algorithms for correcting the dominant distortions present in a time-delay anode; geometric (local) and thermal (global) distortions. These algorithms were developed as part of the data reduction pipelines for the Cosmic Origins Spectrograph (COS), a fourth generation instrument for the Hubble Space Telescope, and the Far Ultraviolet Spectroscopic Explorer (FUSE).

The dynamic solar atmosphere poses a severe observational challenge for imaging spectroscopy in EUV. The traditional method of building up images by rastering a slit spectrograph has so far proven too slow to keep up with the Sun's rapidly changing transition region and corona. We describe a new approach, using a slitless imaging spectrograph operating in a narrow band, with imaging detectors at three orders. This arrangement offers cotemporal imaging and spectroscopy at high spatial, spectral, and temporal resolution. The prospect of disentangling spatial and spectral information is greatly improved by choosing a narrow band containing only two spectral lines, and by imaging at several spectral orders. This paper discusses several advantages and challenges of the multi-order slitless approach. We derive a mathematical description of the null space of spatial-spectral signatures to which an ideal three-order slitless spectrograph has zero response. An exploration of the null space helps to clarify the capabilities and limitations of this instrument type. We infer that the three-order slitless spectrograph is sensitive to line intensity, doppler shift and line width; but insensitive to line asymmetry. Strategies are developed to minimize the ambiguity in interpreting the multi-order data. A proof of concept sounding rocket payload, the Multi-Order Solar EUV Spectrograph (MOSES), is under development with an anticipated launch in Spring, 2004.

For future spacecrafts a lot of new UV or x-ray instruments are proposed. To enhance resolution and reduce scattering, new optical materials with optical surfaces with a roughness range of about 0.1 nm, i.e. supersmooth surfaces will be used to build the optics of the instruments. Some of the spacecrafts or instruments will be operated in the Low Earth Orbits (LEO's) of the Space Shuttle or the International Space Station. The natural and induced space environment can damage spacecraft and instrument materials. Since the LDEF-EURECA- and D2-experiments and the recovery of the Hubbel Space Telescope solar arrays it is well known that a large group fo materials degrade under space conditions. However very few data are available from inflight experiments especially on supersmooth materials. To fill the gap, the Surface Effects Sample Monitor SESAM has been developed. This space flight instrument was designed to expose test materials to the conditions of space during flight missions. Also included in the experiment is an online Atomic Oxygen (ATOX) Measurement Facility to monitor the impact of the ATOX on the exposed samples. The experiment was flown on four missions. The results show a degradation of supersmooth samples under space conditions which has to taken in account for the design of future UV or X-ray instruments.