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We establish a viable laser payload design for the Orbiting Configurable Artificial Star (ORCAS) mission. We share observational considerations and derive the engineering requirements for the laser payload. Developed by general Atomics Electromagnetic Systems, the dual-wavelength laser will operate at 1064 nm and can be frequency-doubled to 532 nm, with two possible beam divergence modes and tunable power. The laser payload can be operated at pulse repetition rates greater than 10 kHz to enable compatibility with Adaptive Optics systems and to maintain pointing requirements. We show that such a laser payload can be constructed based upon a high-TRL amplified fiber laser Communication Terminal modified to meet the mission requirements.

In this paper, we establish the mission operation concept for the Orbiting Configurable Artificial Star mission, a hybrid space-ground observatory, which aims to enable ground observations of near-diffraction limited resolution and exquisite sensitivity. We present the mission requirements, introduce a potential orbit solution that can meet them, detail the concrete operational steps to be taken to enable such observations, and develop a mission planning tool which generates a mission schedule that meets all mission requirements and can be altered in real time in the case of disruptions to the mission. Finally, we show the the mission could enable 300 adaptive optics and 1500 flux calibration observations throughout its lifetime.

We’ve come a long way since 1609, from spectacle lenses to mirrors in space, from twitching frog legs to the Event Horizon Telescope observing a black hole. But far more is possible. On the ground, a new generation of optical telescopes is under construction, up to 39 m in diameter. Adaptive optics compensates for the turbulent atmosphere, but could work far better with an orbiting reference beacon in space. Bright chemiluminescent emission lines in the upper atmosphere interfere with observations, but could be blocked by fiber optic filters. Energy-resolving photon counting detectors promise far greater sensitivity. New ways of making mirrors offer far better resolution for space X-ray telescopes. Coronagraphs can suppress starlight enough to reveal exoplanets in direct imaging, or starshades can cast star shadows on telescopes to do the same thing. New generations of far IR detectors with large cryogenic telescopes in space can reveal the cool and cold universe. Radio telescopes on the quiet far side of the Moon can overcome the limits of the ionosphere and intense local interference to see events in the early universe as it heated up again after the Big Bang expansion cooled everything. Neutrino telescopes can see stars being shredded by black holes, and gravitational wave detectors see merging neutron stars and black holes. Atom wave gravimeters can measure the internal structure of planets and asteroids, and sample return missions are already bring back distant bits of the solar system. What will happen next? I don’t know but it will be glorious.

We lay out the capabilities and limitations of starshade-based missions aiming to measure the reflected light spectra of temperate planets from an imaging perspective. We use the Starshade Imaging Simulation Toolkit for Exoplanet Reconnaissance to conduct high fidelity end-to-end optical simulations, taking a step forward from simplified analytical equations, exploring and quantifying the impact of an array of observational conditions, including natural parameters such as target star types, planet types, distances, planet phases, and exo-zodiacal dust, and starshade perturbations such as tilt, shift off line of sight, edge errors, and glint. We find that signal-to-noise ratio (SNR) requirements used for establishing detection and spectral characterization, is not suitable under realistic observation conditions for a wide range of targets. We show that even if we assume that the spatially distributed, time-varying background noise could be known and calibrated to a level of 1%, each target star will need its own SNR requirement based on its unique observation conditions, nearly always resulting in a higher threshold SNR, with values as high as X5 from currently established requirement, and in some cases impossible to detect. We conduct statistical analysis using end-to-end optical simulations, taking into account observationally based priors and update previously established completeness values for an array of target stars and mission configurations, accounting for starshade perturbations, and background knowledge at a level of one percent and find that completeness values are negatively impacted and reduced by up to 50% across targets even at ranges shorter than 10 pc. Finally, we utilize information from over hundreds of thousands of detailed imaging simulations to map accessible target stars for both optimistic and pessimistic scenarios, reassessing the expected capabilities of starshade-based high contrast direct imaging missions.

This paper addresses the orbit design and translational control problems for a new class of astrophysics missions that require regular periods of accurate alignment between a ground-based sensor, a space-based instrument, and an inertial target such as a star or galaxy. These problems must be solved to enable novel missions such as the Earth-Orbiting Starshade, which uses a 100m starshade with extremely large ground telescopes to image earth-like exoplanets with an effective inner working angle of only 50 milliarcseconds. The orbit design and control problems for these missions are challenging because the spacecraft must perform autonomous accurate formation-flying with a telescope that is not in orbit while satisfying multiple requirements on the optical and orbit configurations. To meet this need, this paper includes four contributions to the state-of-the-art. First, analytical constraints on key design variables are derived to guarantee the existence of regular observation opportunities that satisfy all mission requirements. Second, the delta-v cost of the station-keeping maneuvers required to maintain alignment between the sensor, instrument, and target is derived in closed-form as a function of the location of the target, the latitude of the sensor, and the start time and duration of the observation. This derivation provides simple design rules to minimize the delta-v cost of observations. Also, it is demonstrated that chemical propulsion is required to counteract the relative acceleration between the sensor and instrument for scientifically useful observation durations. Third, a novel four-impulse maneuver scheme is proposed to minimize the delta-v cost of reconfiguring the orbit to enable observations of multiple targets. It is found that the proposed maneuver scheme can reduce the total delta-v required for a large reconfiguration by up to 44 % compared to simply rotating the orbit plane. Finally, it is demonstrated that a distributed mission architecture can reduce the propellant required to observe each target by several hundred kilograms. Overall, this paper provides a novel orbit design that enables new science missions that require real-time cooperation between ground-based sensors and space-based instruments, providing sensing capabilities that are infeasible with any other mission architecture.

We present the optical requirement-driven observational constraints of the Remote Occulter, an orbiting starshade designed to work with ground-based telescopes to produce visible-band images and spectra of temperate planets around Sun-like stars. We then utilize these constraints to develop and present numerical simulations of time-dependent observable sky regions along with each region’s nightly available exposure duration and show that nearly the entire sky could be observed for up to 8 h a night. We further examine how changes introduced to our established constraints will impact such observational windows and discuss their implications, setting the ground for upcoming studies aiming to further investigate the Remote Occulter mission capabilities and architecture.

The Origins Space Telescope will trace the history of our origins from the time dust and heavy elements permanently altered the cosmic landscape to present-day life. How did galaxies evolve from the earliest galactic systems to those found in the Universe today? How do habitable planets form? How common are life-bearing worlds? To answer these alluring questions, Origins will operate at mid- and far-infrared (IR) wavelengths and offer powerful spectroscopic instruments and sensitivity three orders of magnitude better than that of the Herschel Space Observatory, the largest telescope flown in space to date. We describe the baseline concept for Origins recommended to the 2020 US Decadal Survey in Astronomy and Astrophysics. The baseline design includes a 5.9-m diameter telescope cryocooled to 4.5 K and equipped with three scientific instruments. A mid-infrared instrument (Mid-Infrared Spectrometer and Camera Transit spectrometer) will measure the spectra of transiting exoplanets in the 2.8 to 20 μm wavelength range and offer unprecedented spectrophotometric precision, enabling definitive exoplanet biosignature detections. The far-IR imager polarimeter will be able to survey thousands of square degrees with broadband imaging at 50 and 250 μm. The Origins Survey Spectrometer will cover wavelengths from 25 to 588 μm, making wide-area and deep spectroscopic surveys with spectral resolving power R ∼ 300, and pointed observations at R ∼ 40,000 and 300,000 with selectable instrument modes. Origins was designed to minimize complexity. The architecture is similar to that of the Spitzer Space Telescope and requires very few deployments after launch, while the cryothermal system design leverages James Webb Space Telescope technology and experience. A combination of current-state-of-the-art cryocoolers and next-generation detector technology will enable Origins’ natural background-limited sensitivity.

International audience; The Origins Space Telescope will trace the history of our origins from the time dust and heavy elements permanently altered the cosmic landscape to present-day life. How did galaxies evolve from the earliest galactic systems to those found in the universe today? How do habitable planets form? How common are life-bearing worlds? We describe how Origins was designed to answer these alluring questions. We discuss the key decisions taken by the Origins mission concept study team, the rationale for those choices, and how they led through an exploratory design process to the Origins baseline mission concept. To understand the concept solution space, we studied two distinct mission concepts and descoped the second concept, aiming to maximize science per dollar and hit a self-imposed cost target. We report on the study approach and describe the concept evolution. The resulting baseline design includes a 5.9-m diameter telescope cryocooled to 4.5 K and equipped with three scientific instruments. The chosen architecture is similar to that of the Spitzer Space Telescope and requires very few deployments after launch. The cryo-thermal system design leverages James Webb Space Telescope technology and experience.

Delabrouille, J., et al., This paper discusses the science case for a sensitive spectro-polarimetric survey of the microwave sky. Such a survey would provide a tomographic and dynamic census of the three-dimensional distribution of hot gas, velocity flows, early metals, dust, and mass distribution in the entire Hubble volume, exploit CMB temperature and polarisation anisotropies down to fundamental limits, and track energy injection and absorption into the radiation background across cosmic times by measuring spectral distortions of the CMB blackbody emission. In addition to its exceptional capability for cosmology and fundamental physics, such a survey would provide an unprecedented view of microwave emissions at sub-arcminute to few-arcminute angular resolution in hundreds of frequency channels, a data set that would be of immense legacy value for many branches of astrophysics. We propose that this survey be carried out with a large space mission featuring a broad-band polarised imager and a moderate resolution spectro-imager at the focus of a 3.5 m aperture telescope actively cooled to about 8K, complemented with absolutely-calibrated Fourier Transform Spectrometer modules observing at degree-scale angular resolution in the 10–2000 GHz frequency range. We propose two observing modes: a survey mode to map the entire sky as well as a few selected wide fields, and an observatory mode for deeper observations of regions of specific interest., This work has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement No 725456, CMBSPEC) as well as the Royal Society (grants UF130435 and RG140523). JARM acknowledges financial support from the Spanish Ministry of Science and Innovation (MICINN) under the project AYA2017-84185-P, and from the European Union’s Horizon 2020 research and innovation programme under Grant Agreement 687312 (RADIOFOREGROUNDS). C.H.-M. acknowledges the support of the Spanish Ministry of Science through project PGC2018-097585-B-C21. Financial support from the ASI/Physics Department of the University of Roma–Tor Vergata agreement n. 2016-24-H.0 for study activities of the Italian cosmology community is acknowledged. JLB is supported by the Allan C. and Dorothy H. Davis Fellowship, and has been supported by the Spanish MINECO under grant BES-2015-071307, co-funded by the ESF during part of the development of this work.

The James Webb Space Telescope (Webb) is the largest space telescope realized to-date, with a 6.5 m segmented primary mirror that must be folded to fit within its Ariane 5 launcher fairing. This infrared telescope is passively cooled using a five-layer sunshield that will keep the optical telescope and its four science instruments in the shade throughout the lifetime of the mission in an L2 orbit. Webb's science instruments include near- and mid- infrared imagers and spectrometers that cover the spectral range from 0.6-28.5 μ.m The Webb mission has a long history with numerous first of its kind technology developments, ground support equipment innovations, and algorithmic characterization advances. This conference proceeding summarizes the technical progress over the past two years, from the Spacecraft Element environmental testing to the Observatory integration and testing, and the final Observatory test plans leading up to launch, on-orbit commissioning, and science operations.

The James Webb Space Telescope (JWST) is a large (6.5 m) near- and mid-infrared telescope scheduled for launch in 2021. JWST will be used to explore fundamental questions in astrophysics and planetary science, including the evolution of galaxies, the first light of stars, the formation of stars and planets as well as the characterization of exoplanets. To achieve these scientific goals, NASA and its international partners, the Canadian Space Agency (CSA) and the European Space Agency (ESA), have developed four science instruments for JWST and have prepared detailed commissioning plans for each. The NASA Project Science team has also outlined activities to characterize the performance of the Observatory as a whole. These activities include: 1) monitoring of the instrument and telescope cooldown for contamination mitigation; 2) measurements of straylight and other backgrounds for validation of the JWST stray light models as well as instrument background subtraction algorithms; 3) characterization of optical thermal distortion between its hot and cold telescope pointings within the observable field of regard and 4) trending of observatory performance parameters. Each of these activities has been planned in close collaboration with the observatory wavefront, commissioning planning, and science instrument teams. Here we present the plans for these activities, the expected results and how they will impact future guest observer (GO) proposals and JWST science community.

The Remote Occulter (Orbiting Starshade) is a proposed 100-meter class starshade working with a ground-based telescope, designed for visible-band imaging and spectroscopy of temperate planets around sun-like stars. With advanced adaptive optics and the largest telescopes like the 39 m ELT, it would enable the study of planetary systems and a wide variety of exoplanets. In this paper, we describe the geometrical constraints and establish which parts of the sky are observable.

The Origins Space Telescope will trace the history of our origins from the time dust and heavy elements permanently altered the cosmic landscape to present-day life. How did galaxies evolve from the earliest galactic systems to those found in the universe today? How do habitable planets form? How common are life-bearing worlds? To answer these alluring questions, Origins will operate at mid- and far-infrared wavelengths and offer powerful spectroscopic instruments and sensitivity three orders of magnitude better than that of Herschel, the largest telescope flown in space to date. After a 3 ½ year study, the Origins Science and Technology Definition Team will recommend to the Decadal Survey a concept for Origins with a 5.9-m diameter telescope cryocooled to 4.5 K and equipped with three scientific instruments. A mid-infrared instrument (MISC-T) will measure the spectra of transiting exoplanets in the 2.8 – 20 μm wavelength range and offer unprecedented sensitivity, enabling definitive biosignature detections. The Far-IR Imager Polarimeter (FIP) will be able to survey thousands of square degrees with broadband imaging at 50 and 250 μm. The Origins Survey Spectrometer (OSS) will cover wavelengths from 25 – 588 μm, make wide-area and deep spectroscopic surveys with spectral resolving power R ~ 300, and pointed observations at R ~ 40,000 and 300,000 with selectable instrument modes. Origins was designed to minimize complexity. The telescope has a Spitzer-like architecture and requires very few deployments after launch. The cryo-thermal system design leverages JWST technology and experience. A combination of current-state-of-the-art cryocoolers and next-generation detector technology will enable Origins’ natural backgroundlimited sensitivity.

The mysterious acceleration of the expansion of the Universe, discovered in 1998, can be described by the cosmological constant introduced by Einstein in 1917. In the quantum cosmology, the existence of a repulsive force is associated with "dark energy" - a hypothetical substance with a negative pressure. But numerous attempts to obtain from the quantum theory the observed value of the cosmological constant lead to values of 120 orders of magnitude larger than the observed value. In the bouncing cosmology, a collapse of the Universe of the previous cycle is supposed, and then its new divergence. We consider the bouncing cosmology in the light of the latest discovery of gravitational waves and a large number of massive black holes, which are a probable candidate for the role of dark matter. When the Universe collapses, a significant part of the gravitational mass of the merging black holes turns into gravitational waves. During mergers, the size of black holes increases. We call the largest of them the Big Black Hole (BBH). In the stage of expansion, the frequency of mergers of black holes will decrease sharply and the reverse process will begin due to the absorption of gravitational waves: the slow growth of the mass of black holes, first of all the BBH, which has the maximum surface. If we assume that gravitational radiation themselves do not generate a gravitational field, then it can be shown that a sharp decrease in the gravitational mass of the Universe causes strong antigravity, which can be responsible for the Big Bang. The gravitational mass of BBH at the stage of expansion of the Universe will grow and the gravitational influence of BBH will stretch a field of galaxies. This stretching effect is described by the appearance of a cosmological constant in the Friedmann equations. An estimated value of the cosmological constant is in good agreement with the observations. A cyclic model of the Universe can be developed on the basis of periodic transformation of the mass of merging black holes into gravitational waves and absorption of the background gravitational radiation by the BBH.

Planned for launch in 2019 on an Ariane 5 from French Guiana, JWST will observe at wavelengths from 0.6 to 28 µm with a full suite of imagers, spectrometers, and coronagraphs. JWST will extend the discoveries of the Hubble and Spitzer observatories in all areas from cosmology, galaxies, stars, and exoplanets to our own Solar System. With a 6.5 m primary mirror it has a collecting area 7 times that of Hubble and 50 times that of Spitzer. The image quality is diffraction limited at 2 µm with near IR camera pixels of only 0.03 arcsec. I will outline the planned observing program, showing how the instrument capabilities enable new discoveries in new territories. What were the first objects that formed in the expanding universe? How do the galaxies grow? How are black holes made, ranging from stellar mass to supermassive, over a billion solar masses, and what is their effect on the neighborhood? How are stars and planetary system formed? What governs the evolution of planetary systems, with the possibility of life? How did the Earth become so special? But the most important discoveries will be those we have not even imagined today.

The Space High Angular Resolution Probe for the Infrared (SHARP-IR) is a new mission currently under study. As part of the preparation for the Decadal Survey, NASA is currently undertaking studies of four major missions, but interest has also been shown in determining if there are feasible sub-$1B missions that could provide significant scientific return. SHARP-IR is being designed as one such potential probe. In this talk, we will discuss some of the potential scientific questions that could be addressed with the mission, the current design, and the path forward to concept maturation.

This paper provides a detailed description of the data reduction and analysis procedures that have been employed in our previous studies of spatial fluctuation of the cosmic infrared background (CIB) using deep Spitzer IRAC observations. The self-calibration we apply removes a strong instrumental signal from the fluctuations which would otherwise corrupt our results. The procedures and results for masking bright sources, and modeling faint sources down to levels set by the instrumental noise are presented. Various tests are performed to demonstrate that the resulting power spectra of these fields are not dominated by instrumental or procedural effects. These tests indicate that the large scale (>~30') fluctuations that remain in the deepest fields are not directly related to the galaxies that are bright enough to be individually detected. We provide the parameterization of these power spectra in terms of separate instrument noise, shot noise, and power law components. Our measurements of spatial fluctuations of the CIB intensity indicate the mean emission from the objects producing the fluctuations is quite low (>~1 nW m-2 sr-1 at 3-5 micron), and thus consistent with current gamma-ray absorption constraints. The source of the fluctuations may be high-z Population III objects, or a more local component of very low luminosity objects with clustering properties that differ from the resolved galaxies. Finally, we discuss the prospects of the upcoming space-based surveys to directly measure the epochs inhabited by the populations producing these source-subtracted CIB fluctuations, and to isolate the individual fluxes of these populations.

The simulated Doppler shifts of the solar Mg I Fraunhofer line produced by scattering on the solar light by asteroidal, cometary, and trans-neptunian dust particles are compared with the shifts obtained by Wisconsin H-Alpha Mapper (WHAM) spectrometer. The simulated spectra are based on the results of integrations of the orbital evolution of particles under the gravitational influence of planets, the Poynting–Robertson drag, radiation pressure, and solar wind drag. Our results demonstrate that the differences in the line centroid position in the solar elongation and in the line width averaged over the elongations for different sizes of particles are usually less than those for different sources of dust. The deviation of the derived spectral parameters for various sources of dust used in the model reached maximum at the elongation (measured eastward from the Sun) between 90° and 120°. For the future zodiacal light Doppler shifts measurements, it is important to pay a particular attention to observing at this elongation range. At the elongations of the fields observed by WHAM, the model-predicted Doppler shifts were close to each other for several scattering functions considered. Therefore the main conclusions of our paper do not depend on a scattering function and mass distribution of particles if they are reasonable. A comparison of the dependencies of the Doppler shifts on solar elongation and the mean width of the Mg I line modeled for different sources of dust with those obtained from the WHAM observations shows that the fraction of cometary particles in zodiacal dust is significant and can be dominant. Cometary particles originating inside Jupiter's orbit and particles originating beyond Jupiter's orbit (including trans-neptunian dust particles) can contribute to zodiacal dust about 1/3 each, with a possible deviation from 1/3 up to 0.1–0.2. The fraction of asteroidal dust is estimated to be ∼0.3–0.5. The mean eccentricities of zodiacal particles located at 1–2 AU from the Sun that better fit the WHAM observations are between 0.2 and 0.5, with a more probable value of about 0.3.

NASA's Cosmic Background Explorer satellite mission, the COBE, laid the foundations for modern cosmology by measuring the spectrum and anisotropy of the cosmic microwave background radiation and discovering the cosmic infrared background radiation. I describe the history of the COBE project, its scientific context, the people who built it, and the scientific results. The COBE observed the universe on the largest scales possible by mapping the cosmic microwave and infrared background radiation fields and determining their spectra. It produced conclusive evidence that the hot Big Bang theory of the early universe is correct, showed that the early universe was very uniform but not perfectly so, and that the total luminosity of post--Big Bang objects is twice as great as previously believed. The COBE concept was developed by a Mission Definition Study Team appointed by NASA in 1976, based on three competing proposals submitted in 1974. The COBE was built in-house by Goddard Space Flight Center, with a helium cryostat provided by Ball Aerospace, and was launched on a Delta rocket built by McDonnell Douglas. It is in a circular orbit $900\phantom{\rule{0.3em}{0ex}}\mathrm{km}$ above the Earth, in a plane inclined 99\ifmmode^\circ\else\textdegree\fi{} to the equator and roughly perpendicular to the line to the Sun. It carried three instruments, a far infrared absolute spectrophotometer (FIRAS), a differential microwave radiometer with three channels (DMR), and a diffuse infrared background experiment (DIRBE). The helium cryostat cooled the FIRAS and DIRBE for $10\phantom{\rule{0.3em}{0ex}}\text{months}$ until the helium was exhausted, but operations continued for a total of $4\phantom{\rule{0.3em}{0ex}}\text{years}$. Subsequent observations have confirmed the COBE results and led to measurements of the main cosmological parameters with a precision of a few percent.

We study the possible contribution of optical galaxies detected with the Hubble ACS instrument to the near-IR cosmic infrared (CIB) fluctuations in deep Spitzer images. The Spitzer data used in this analysis are obtained in the course of the GOODS project, from which we select four independent 10' × 10' regions observed at both 3.6 and 4.5 μm. ACS source catalogs for all of these areas are used to construct maps containing only their emissions in the ACS B,V,i,z bands. We find that deep Spitzer data exhibit CIB fluctuations remaining after removal of foreground galaxies of a very different clustering pattern at both 3.6 and 4.5 μm than the ACS galaxies could contribute. We also find that there are very good correlations between the ACS galaxies and the removed galaxies in the Spitzer maps, but practically no correlations remain with the residual Spitzer maps used to identify the CIB fluctuations. These contributions become negligible on larger scales used to probe the CIB fluctuations arising from clustering. This means that the ACS galaxies cannot contribute to the large-scale CIB fluctuations found in the residual Spitzer data. The absence of their contributions also means that the CIB fluctuations arise at z 6.5 as the Lyman break of their sources must be redshifted past the longest ACS band, or the fluctuations have to originate in the more local but extremely low luminosity galaxies.

A proof-of-concept dual-band dual-mode 25/44-GHz electronically scanned array (ESA) is realized using electromagnetic crystal (EMXT) waveguide sidewalls developed at the Rockwell Scientific Company (RSC) and Rockwell Collins, Inc. (RCI). A 15-element one-dimensional (1-D) linear array was tested at the RCI near field antenna range to show frequency independence and beam steering capability. The results of these tests are presented herein.

We introduce a memory-efficient method for processing up-the-ramp sampled data to reduce noise and remove cosmic-ray events. The method we describe includes initial processing in the readout electronics (onboard, in the case of a space mission) plus postprocessing downstream. This data processing approach can be used to record or downlink high-quality science data using a small fraction of the bits required to transmit the full data, potentially reducing the volume to 0.01-0.001 of its original size. The onboard component has the advantage that it "processes as you go," reducing the online memory requirements. The processing and memory requirements are modest and are within the scope of current-generation avionics systems. We discuss the requirements and the performance of the algorithm. We also demonstrate the quality of the resulting data.

We integrated the orbital evolution of 30,000 Jupiter-family comets, 1300 resonant asteroids, and 7000 asteroidal, trans-Neptunian, and cometary dust particles. For initial orbital elements of bodies close to those of Comets 2P, 10P, 44P, and 113P, a few objects got Earth-crossing orbits with semi-major axes $a$$, Comment: Submitted to Proc. of the IAU Colloquium N 197 "Dynamics of populations of planetary systems" (Belgrade, Serbia and Montenegro, 31 August - 4 September, 2004)

Current thinking about the Moon as a destination has revitalized interest in lunar astronomical observatories. Once seen by a large scientific community as a highly enabling site, the dramatic improvement in capabilities for free-space observatories prompts reevaluation of this interest. Whereas the lunar surface offers huge performance advantages for astronomy over terrestrial sites, free-space locales such as Earth orbit or Lagrange points offer performance that is superior to what could be achieved on the Moon. While astronomy from the Moon may be cost effective once infrastructure is there, it is in many respects no longer clearly enabling compared to free-space., 14 pages, 1 figure; in press Space Policy

Our efficient numerical approach has been applied to modeling the asymmetric circumstellar dust disk around β Pictoris as observed with the HST/STIS. We present a new model on the origin of the warping of the β Pic disk. We suggest that the observed warp is formed by the gravitational influence of a planet with a mass of about 10 masses of Earth, at a distance of 70 AU, and a small inclination (∽ 2.5°) of the planetary orbit to the main dust disk. Results of our modeling are compared with the STIS observations.

In the spirit of the Lindau Meeting, we present a dialogue between a Nobel laureate and a young researcher. This interchange started online, where it continues to unfold. Here is a digest of this conversation, which has developed across time and space.

This is one of two papers in which we report the detection of structure in the cosmic infrared background (CIB) between 1.25 - 2.2 micron through the use of data from the Two Micron Sky Survey (2MASS). This paper concentrates on data assembly, analysis and the estimate of the various foreground contributions; the companion paper (Kashlinsky, Odenwald, Mather, Skrutskie, Cutri 2002, hereafter KOMSC) presents the cosmological results for the CIB fluctuations and their implications. By using repeated observations of a specific calibration star field, we were able to achieve integration times in excess of 3900 seconds compared to the 7.8 seconds in the standard 2MASS data product. This yielded a point source detection limit (3 \sigma) of +18.5^m in K_s band. The resulting co-added images were processed to remove point sources to a limiting surface brightness of +20^m/arcsec$^2 or 40 nW/m^2/sr. The remaining maps contained over 90% of the pixels and were Fourier transformed to study the spatial structure of the diffuse background light. After removing resolved sources and other artifacts, we find that the power spectrum of the final images has a power-law distribution consistent with clustering by distant galaxies. We estimate here the contributions to this signal from Galactic foregrounds, atmospheric OH-glow, zodiacal light and instrument noise, all of which are small and of different slopes. Hence, this supports the KOMSC identification of the signal as coming from the CIB fluctuations produced by distant clustered galaxies.

The cosmic microwave background (CMB) spectral results of the Far-Infrared Absolute Spectrophotometer (FIRAS) instrument are summarized. Some questions that have been raised about the calibration accuracy are also addressed. Finally, we comment on the potential for major improvements with new measurement approaches. The measurement of the deviation of the CMB spectrum from a 2.725 ± 0.001 K blackbody form made by the COBE-FIRAS could be improved by nearly 2 orders of magnitude.

We report first results for the cosmic infrared background (CIB) fluctuations at 1.25, 1.65 and 2.17 micron obtained from long exposures constructed from 2MASS standard star fields. We have co-added and analyzed scans from one such field with a total exposure time > 1 hour, and removed sources and other artifacts. The stars and galaxies were clipped out to K_s~19^m leaving only high-z galaxies (or possibly local low-surface-brightness systems). The residual component of the diffuse emission on scales from a few arc-sec to a few arc-min has a power-law slope consistent with emission produced by clustered galaxies. The noise (and residual artifacts) contribution to the signal is small and the colors of the signal are very different from Galactic stars or air-glow. We therefore identify the signal as CIB fluctuations from the faint unresolved galaxies. We show that the present-day galaxies with no evolution would produce a significant deficit in the observed CIB fluctuations. Thus the dominant contribution to the observed signal must come from high z and may indicate high rates of star formation at those epochs., Ap. J. Letters, in press

We present new methodology to use cosmic infrared background (CIB) fluctuations to probe sources at 1030., Comment: ApJ, in press. Minor revisions/additions to match the version in proofs

This paper reports results of a four-year industrial consortium effort to develop lead-free solders for high-temperature applications (up to 160°C). Work included preliminary evaluations of 32 tin-based alloys, a screening of the thermomechanical fatigue performance of 13 promising alloys, and a full manufacturability and fatigue testing of the seven most promising of those alloys, namely Sn-3.5Ag, Sn-4Ag-1Cu, Sn-4Ag-0.5Cu, Sn-2.5Ag-0.8Cu-0.5Sb, Sn-4.6Ag-1.6Cu-1Sb-1Bi, Sn-3.3Ag-1Cu-3.3Bi, and Sn-3.5Ag-1.5In (compositions in weight percent). Eight different components were used on the reliability test vehicle, and the alloys were compared through Weibull analysis. In addition, the same seven experimental alloys were tested with ball grid array packages cycled up to 100°C or 125°C. All the lead-free alloys performed well, but those containing bismuth showed especially outstanding performance. In general, the ternary and higher alloys performed as well or better than the industry standard tin-silver eutectic, suggesting that solders other than the tin-silver eutectic should be considered for high-reliability, high-temperature applications.

We examine cosmic ray rejection methodology on data collected from InSb and Si:As detectors. The application of an Up-the-Ramp sampling technique with cosmic ray identification and mitigation is the focus of this study. This technique is valuable for space-based observatories which are exposed to high-radiation environments. We validate the Up-the-Ramp approach on radiation-test data sets with InSb and Si:As detectors which were generated for SIRTF. The Up-the-Ramp sampling method studied in this paper is over 99.9% effective at removing cosmic rays and preserves the structure and photometric quality of the image to well within the measurement error.

The Next Generation Space Telescope (NGST) will be an 8 m deployable telescope, radiatively cooled to 30 K and diffraction-limited at 2 μm, operating at the Sun-Earth Lagrangian point L2. It will be built by a partnership of NASA, ESA, and CSA (Canadian Space Agency). The camera sensitivity should be limited by the zodiacal light for wavelengths < 10 μm. The main scientific objectives are the study of the origin and evolution of galaxies, stars, and planets, beginning with the first luminous objects to form from the Big Bang. Other objectives include studies of dark matter, supernovae, the intergalactic medium, gamma ray bursts, star ages, and exobiology. The telescope will be operated like the Hubble Space Telescope (HST) by the Space Telescope Science Institute, with all observing programs openly solicited and selected by peer review.The NGST scientific requirements originated with the report of the Dressler Committee HST & Beyond. The instruments recommended by the Ad Hoc Science Working Group (ASWG) include 1) a wide field near infrared (NIR) camera with an 8K2 detector array covering 0.6 - 5 μm, 2) a multi-object NIR spectrograph capable of simultaneously observing > 100 objects with a resolution of R (λ/δλ) = 1000, and 3) a combined mid-infrared (MIR) camera and spectrograph from 5-27 μm, with a resolution of R > 1500.