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All sourcesNASA NTRSDOE OSTI
NASA NTRS2019

A common platform for DSN receiver development

NASA's Deep Space Network is currently updating a number of sub systems within the Signal Processing Centers at its Deep Space Communication Complexes in order to modernize aging equipment in the downlink receivers for telemetry, tracking, radio science, and radio astronomy. To reduce development costs and increase commonality among these traditionally custom-built receivers, the implementation team has developed a flexible architecture built primarily around commercial off-the-shelf hardware compliant with the Micro Telecommunications Computing Architecture (uTCA) specification and commercial high speed 10Gbit Ethernet switches. Custom firmware and software are being developed to perform the required signal processing functions needed to replace the legacy systems in a phased implementation approach which establishes a new digital Intermediate Frequency (IF) signal distribution system first, followed by implementations of various receiver functions as dictated by need. The first of these new receivers, the Open Loop Receiver, will come online in the Fall of 2018. A description of the new architecture, referred to as the “Common Platform”, will be provided followed by an overview of the phased implementation approach and initial OLR performance results.

Navarro, Robert↗
NASA NTRS1997

Sofia Science Working Group

The purpose of this grant was to enable the Principal Investigator (P.I.) to travel to and participate in the meetings and activities of the NASA SOFIA Science Working Group (SSWG), and to spend time working on some of the associated technical issues relating to the SOFIA (Stratospheric Observatory for Infrared Astronomy) project. The SOFIA Science Working Group was established to help develop the plans and specifications for the next-generation airborne observatory ("SOFIA"), which is now under development. The P.I. was asked to serve on the SSWG due to his experience in airborne astronomy: he has developed several astronomical instruments for the Kuiper Airborne Observatory NASA's previous airborne astronomy platform (which was decommissioned in 1995 in preparation for SOFIA). SOFIA, which will be a 747 SP aircraft carrying a 2.7 meter diameter telescope, is a joint project sponsored by NASA and DLR (the German space agency), and is now under development by a consortium including Universities Space Research Association (USRA), Raytheon, Sterling Software, and United Airlines. Further details on the SOFIA project can be found on the internet at http: //sofia. arc. nasa. gov. Rather than develop the SOFIA observatory in-house, NASA decided to privatize the project by issuing a Request for Proposals (RFP). The respondents to this RFP were consortia of private organizations which together had the required facilities and expertise to be able to carry out the project; the winner was the group led by USRA. One of the main roles of the SSWG was to help develop the technical specifications for the SOFIA observatory. In particular, the SSWG provided advice to NASA on the specifications that were written into the RFP, particularly those which had an important impact on the scientific productivity of the observatory. These specifications were discussed at the meetings of the SSWG, which were held primarily at NASA/Ames (in California) and at NASA Headquarters (in Washington DC). Apart from these meetings, members of the SSWG were expected to perform more detailed analyses of the impact of certain parameters and specifications on the performance of astronomical instruments. The SSWG ended its activities with the selection of the USRA team in January 1997.

Zmuidzinas, J.↗
NASA NTRS1997

SOFIA Science Working Group

The SOFIA Science Working Group was established to help develop the plans and specifications for the next-generation airborne observatory ("SOFIA"), which is now under development. The P.I. has developed several astronomical instruments for the Kuiper Airborne Observatory, NASA's previous airborne astronomy platform (which was decommisioned in 1995 in preparation for SOFIA). SOFIA, which will be a 747 SP aircraft carrying a 2.7 meter diameter telescope, is a joint project sponsored by NASA and DLR (the German space agency), and is now under development by a consortium including Universities Space Research Association (USRA), Raytheon, Sterling Software, and United Airlines. Rather than develop the SOFIA observatory in-house, NASA decided to privatize the project by issuing a Request for Proposals (RFP). The respondents to this RFP were consortia of private organizations which together had the required facilities and expertise to be able to carry out the project; the winner was the group led by USRA. One of the main roles of the SSWG was to help develop the technical specifications for the SOFIA observatory. In particular, the SSWG provided advice to NASA on the specifications that were written into the RFP, particularly those which had an important impact on the scientific productivity of the observatory. These specifications were discussed at the meetings of the SSWG, which were held primarily at NASA/Ames (in California) and at NASA Headquarters (in Washington DC). Apart from these meetings, members of the SSWG were expected to perform more detailed analyses of the impact of certain parameters and specifications on the performance of astronomical instruments. The SSWG ended its activities with the selection of the USRA team in January 1997.

Zmuldzinas, J.↗
NASA NTRS1988

A search for narrow band signals with SERENDIP II: a progress report

Commensal programs for the Search for Extraterrestrial Intelligence (SETI), carried out concurrently with conventional radio astronomical observing programs, can be an attractive and cost-effective means of exploring the large multidimensional search space intrinsic to this effort. Our automated commensal system, SERENDIP II, is a high resolution 131,072 channel spectrometer. It searches for 0.49 Hz signals in sequential 64,700 Hz bands of the IF signal from a radio telescope being used for an astronomical observation. Upon detection of a narrow band signal with power above a preset threshold, the frequency, power, time, and telescope direction are recorded for later study. The system has been tested at the Hat Creek Radio Astronomy Observatory 85 ft telescope and the NASA-JPL Deep Space Station (DSS 14) 64 m telescope. It is currently collecting data at the National Radio Astronomy Observatory 300 ft telescope.

Non-NASA Center↗
NASA NTRS2004

Transitsearch Workshop

The discovery of more than 100 planets around nearby solar-like stars that surpass Jupiter in size yet orbit their stars more quickly than Mercury has heralded a new era in astronomy. These enigmatic 'Hot-Jupiters' are large enough and close enough to their parent stars that their 'transits' can be captured by astronomers equipped with a small computer controlled telescope and a quality electronic CCD camera. The planet reveals its presence through the periodic decrease in brightness as it passes (or transits) in front of the star as seen from Earth. The first known transiting extrasolar planet HD 209458b, in the constellation Pegasus, has been the subject of hundreds of scientific papers since its discovery in 1999. The transit of 8th magnitude HD 209458 has been observed by at least a dozen non-professional astronomers using telescopes as small as 4 inches in aperture. Using equipment already in hand, and armed with target lists, transit time predictions, observing techniques and software procedures developed by astronomers at NASA's Ames Research Center and the University of California at Santa Cruz, non-professional astronomers can contribute significantly to the study of extrasolar planets by carefully measuring the brightness of stars with known Hot-Jupiters. In this way, we may resume (after a two century interruption!) the tradition of planetary discoveries by amateur astronomers begun with William Herschel's 1787 discovery of the 'solar' planet Uranus. In the few years transitsearch has been in existence, investigators Tim Castellano (NASA Ames) and Greg Laughlin (UCSC) have written articles for Sky and Telescope and Astronomy magazines, have been featured in stories by the Reuters News Service, Nature magazine, Science magazine, Space.com, the American Institute of Physics and others and received several hundred thousand total hits on their website www.transitsearch,org.

Castellano, T.↗
DOE OSTI2023

Science Reach of the SuperCDMS SNOLAB Experiment (Final Report)

The work carried out as part of this project focuses on the development of software tools to calculate the scientific reach of the SuperCDMS dark matter detection experiment, and to enable projection of the potential reach of future experiments base on this technology.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
NASA NTRS1976

HEAO attitude control subsystem - A multimode/multimission design

The initial three satellites in the High Energy Astronomy Observatory (HEAO) series are in the final development stages with the first launch to be in April 1977. The overall program design concept stressed cost reduction through use of hardware standardization for the three configurations and missions. The Attitude Control and Determination Subsystem (ACDS) developed for HEAO was able to achieve significant design commonality in both hardware and software in an implementation which satisfied the performance requirements of the different missions. The ACDS thus provides an example of a multimode/multimission design which should soon be operational.

Hoffman, D. P.↗
NASA NTRS1992

Astronomical CCD observing and reduction techniques

CCD instrumentation and techniques in observational astronomy are surveyed. The general topics addressed include: history of large array scientific CCD imagers; noise sources and reduction processes; basic photometry techniques; introduction to differential time-series astronomical photometry using CCDs; 2D imagery; point source spectroscopy; extended object spectrophotometry; introduction to CCD astrometry; solar system applications for CCDs; CCD data; observing with infrared arrays; image processing, data analysis software, and computer systems for CCD data reduction and analysis. (No individual items are abstracted in this volume)

Howell, Steve B.↗
DOE OSTI2021

IGRINS RV: A Precision Radial Velocity Pipeline for IGRINS Using Modified Forward Modeling in the Near-infrared

Application of the radial velocity (RV) technique in the near-infrared is valuable because of the diminished impact of stellar activity at longer wavelengths, making it particularly advantageous for the study of late-type stars but also for solar-type objects. In this paper, we present the IGRINS RV open-source python pipeline for computing infrared RV measurements from reduced spectra taken with IGRINS, an R ≡ λ/Δλ ∼ 45,000 spectrograph with simultaneous coverage of the H band (1.49–1.80 μm) and K band (1.96–2.46 μm). Using a modified forward-modeling technique, we construct high-resolution telluric templates from A0 standard observations on a nightly basis to provide a source of common-path wavelength calibration while mitigating the need to mask or correct for telluric absorption. Telluric standard observations are also used to model the variations in instrumental resolution across the detector, including a yearlong period when the K band was defocused. Without any additional instrument hardware, such as a gas cell or laser frequency comb, we are able to achieve precisions of 26.8 m s{sup −1} in the K band and 31.1 m s{sup −1} in the H band for narrow-line hosts. These precisions are empirically determined by a monitoring campaign of two RV standard stars, as well as the successful retrieval of planet-induced RV signals for both HD 189733 and τ Boo A; furthermore, our results affirm the presence of the Rossiter–McLaughlin effect for HD 189733. The IGRINS RV pipeline extends another important science capability to IGRINS, with publicly available software designed for widespread use.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
NASA NTRS1980

Automation of the Mark 3 field system

The software and hardware components which will enable hands off operation are described. The operation of the field system begins with the scheduling of observations. An interactive program, SKED, provides displays of mutual visibility, automatic calculation of telescope slewing times, and the ability to list and edit the schedule. The output of SKED is a schedule file containing commands in the Standard Notation for Astronomy Procedures (SNAP) language which the field system uses for controlling events during the experiment. The most important features of SNAP include sophisticated time sequencing of events, automatic logging of all commands and responses, and the ability to define often used sequences of commands as procedures. A control program, BOSS, running in an HP 1000 minicomputer, reads the SNAP commands from a schedule file and interprets them in terms of commands and requests to devices. Interactive command input is possible through the operator's display terminal. Communication with all of the Mark 3 electronics modules is done via a small general purpose interface board (a microprocessor based ASCII transceiver) which has been installed in each module. Additional devices are controlled and monitored using the IEEE 488 General Purpose Interface Bus.

Vandenbere, N. R.↗
NASA NTRS1981

Orbital operations with the Shuttle Infrared Telescope Facility /SIRTF/

The Shuttle Infrared Telescope Facility (SIRTF) is a cryogenically-cooled, 1-m-class telescope that will be operated from the Space Shuttle as an observatory for infrared astronomy. This paper discusses the scientific constraints on and the requirements for pointing and controlling SIRTF as well as several aspects of SIRTF orbital operations. The basic pointing requirement is for an rms stability of 0.25 arcsec, which is necessary to realize the full angular resolution of the 5-micron diffraction-limited SIRTF. Achieving this stability requires the use of hardware and software integral to SIRTF working interactively with the gyrostabilized Shuttle pointing-mount. The higher sensitivity of SIRTF, together with orbital and time constraints, puts a premium on rapid target acquisition and on efficient operational and observational procedures. Several possible acquisition modes are discussed, and the importance of source acquisition by maximizing the output of an infrared detector is emphasized.

Werner, M. W.↗
NASA NTRS2000

Using XML and Java for Astronomical Instrumentation Control

Traditionally, instrument command and control systems have been highly specialized, consisting mostly of custom code that is difficult to develop, maintain, and extend. Such solutions are initially very costly and are inflexible to subsequent engineering change requests, increasing software maintenance costs. Instrument description is too tightly coupled with details of implementation. NASA Goddard Space Flight Center is developing a general and highly extensible framework that applies to any kind of instrument that can be controlled by a computer. The software architecture combines the platform independent processing capabilities of Java with the power of the Extensible Markup Language (XML), a human readable and machine understandable way to describe structured data. A key aspect of the object-oriented architecture is software that is driven by an instrument description, written using the Instrument Markup Language (IML). ]ML is used to describe graphical user interfaces to control and monitor the instrument, command sets and command formats, data streams, and communication mechanisms. Although the current effort is targeted for the High-resolution Airborne Wideband Camera, a first-light instrument of the Stratospheric Observatory for Infrared Astronomy, the framework is designed to be generic and extensible so that it can be applied to any instrument.

Ames, Troy↗
DOE OSTI2021

Phase-curve Pollution of Exoplanet Transmission Spectra

The occurrence of a planet transiting in front of its host star offers the opportunity to observe the planet’s atmosphere filtering starlight. The fraction of occulted stellar flux is roughly proportional to the optically thick area of the planet, the extent of which depends on the opacity of the planet’s gaseous envelope at the observed wavelengths. Chemical species, haze, and clouds are now routinely detected in exoplanet atmospheres through rather small features in transmission spectra, i.e., collections of planet-to-star area ratios across multiple spectral bins and/or photometric bands. Technological advances have led to a shrinking of the error bars down to a few tens of parts per million (ppm) per spectral point for the brightest targets. The upcoming James Webb Space Telescope (JWST) is anticipated to deliver transmission spectra with precision down to 10 ppm. The increasing precision of measurements requires a reassessment of the approximations hitherto adopted in astrophysical models, including transit light-curve models. Recently, it has been shown that neglecting the planet’s thermal emission can introduce significant biases in the transit depth measured with the JWST/Mid-InfraRed Instrument, integrated between 5 and 12 μm. In this paper, we take a step forward by analyzing the effects of the approximation on transmission spectra over the 0.6–12 μm wavelength range covered by various JWST instruments. We present open-source software to predict the spectral bias, showing that, if not corrected, it may affect the inferred molecular abundances and thermal structure of some exoplanet atmospheres.

47 OTHER INSTRUMENTATION↗
NASA NTRS1982

Investigations in cosmic and gamma ray astronomy and nuclear instruments

The Nuclear Radiation Monitor (NRM) is flying on the Spacelab 2 vehicle as part of a set of instrumentation designed to measure the ambient physical environment on Spacelab in orbit. The NRM measures the natural and induced gamma ray activity. The instrument is constituted of a 25 sq in (NaI (T1)) crystal viewed with a single phototube and surrounded by a plastic anticoincidence shield. It is mounted on a pedestal and placed, with its electronics, on the Spacelab pallet. The detector head was designed and a development model fabricated and tested. Extensive software studies for on board and GSE microprocessors for use with the NRM were also made.

Gregory, J. C.↗
DOE OSTI2021

Filling the black hole mass gap: Avoiding pair instability in massive stars through addition of nonnuclear energy

In standard stellar evolution, stars with masses ranging from approximately 150 to 240M ⊙ are expected to evolve to a pair instability supernova with no black hole (BH) remnant. This evolutionary behavior leads to a predicted gap in the black hole mass function from approximately 50 to 140M ⊙ . Yet the LIGO and Virgo Collaborations recently discovered black holes of masses 66M ⊙ and 85M ⊙ in the gravitational wave event GW190521. Here, we propose a new method to populate the BH mass gap. If an energy source is added throughout the star in addition to nuclear fusion, it is possible for the altered evolution to avoid the complete destruction of a pair instability supernova, and instead a BH remnant is left behind. An example of an extra energy source is dark matter annihilation within the star, but our results hold more generally. We show this phenomenon by exploring the effect of adding an energy source independent of temperature and density to a 180M ⊙ star, using the MESA one-dimensional stellar evolution software. If ~50% of the star’s energy is due to this new source, the star is capable of avoiding the pair instability entirely and evolving towards a core-collapse supernova and ultimately a BH remnant with mass ~ 120M ⊙ .

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2023

Curifactory: A research experiment manager

Curifactory is a command line tool and framework for organizing Python experiment code, configuration parameters, and results. It is an opinionated and lightweight approach to workflow management infrastructure and is primarily intended to support researchers conducting experiments on one machine. This software was developed to support the reproducibility of results for several data science projects in the Nuclear Nonproliferation Division at Oak Ridge National Laboratory. Curifactory is intended to be a general framework and is not specific to machine learning or data science. It can aid in any field in which experiments are primarily computation-based studies and can be implemented in Python (e.g., high-energy physics, astronomy, computational chemistry). Here, the design emphasizes the automated caching of intermediate data analysis artifacts to speed up development involving computationally intensive tasks. It also allows for data provenance and experiment reproduction. Individual experiment runs are tracked through logs and their output reports, and entire copies of a run with all cached data and metadata can be exported for others to run using Curifactory on another machine. Curifactory experiments can either be integrated into a project from the beginning or can be written on top of an existing codebase without needing significant modification. A few important views of the Curifactory library can be seen in Figure 1.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2024

Assessing and benchmarking the fidelity of posterior inference methods for astrophysics data analysis

In this era of large and complex astronomical survey data, interpreting, validating, and comparing inference techniques becomes increasingly difficult. This is particularly critical for emerging inference methods like Simulation-Based Inference (SBI), which offer significant speedup potential and posterior modeling flexibility, especially when deep learning is incorporated. We present a study to assess and compare the performance and uncertainty prediction capability of Bayesian inference algorithms – from traditional MCMC sampling of analytic functions to deep learning-enabled SBI. We focus on testing the capacity of hierarchical inference modeling in those scenarios. Before we extend this study to cosmology, we first use astrophysical simulation data to ensure interpretability. We demonstrate a probabilistic programming implementation of hierarchical and non-hierarchical Bayesian inference using simulations derived from the DeepBench software library, a benchmarking tool developed by our group that generates simple and controllable astrophysical objects from first principles. This study will enable astronomers and physicists to harness the inference potential of these methods with confidence.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
NASA NTRS2002

Transit Detection with a Distributed Network of Telescopes

The discovery since 1995 of more than 80 planets around nearby solar-like stars and the photometric detection of a transit of the planet orbiting HD 209458 (producing a more than 1% drop in brightness that lasts 3 hours) has heralded a new era in astronomy. It has now been demonstrated that small telescopes equipped with sensitive and stable electronic detectors can produce fundamental scientific discoveries regarding the frequency and nature of planets outside the solar system. The modest equipment requirements for the measurement of extrasolar planetary transits are achieved by commercial small aperture telescopes and CCD imagers common among amateur astronomers. With equipment already in hand and armed with target lists, observing techniques and software procedures developed b NASA's Ames Research Center and the University of California at Santa Cruz, non-professional astronomers can contribute significantly to the study of planets around others stars. Statistical analyses of the population of parent stars of the known extrasolar planets indicate that approximately one in ten metal-rich stars should harbor a short-period planet. Given the ten percent chance that a given short-period planet displays transits, we therefore expect that approximately 1% of the most metal rich stars will have a planetary companion detectable by this project. A catalog of 206 highly metal rich nearby F, G and K stars has been compiled, and this catalog will provide a rich source of targets. In addition, main sequence F, G, K and M stars identified to have "transit-like" features in the Hipparcos satellite photometry archive will also be monitored. A commercially available "amateur grade" telescope/CCD/software system acquired late during the 2001 "transit season" for HID 209458 has achieved 0.47% RMS precision for 13 minute time sampling from a suburban backyard under less than ideal observing conditions and a realistic range of airmass values.

Castellano, T.↗