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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
NASA NTRS2006

The Fourier-Kelvin Stellar Interferometer a Low Complexity, Low Cost Space Mission for High-Resolution Astronomy and Direct Exoplanet Detection

The Fourier-Kelvin Stellar Interferometer (FKSI) is a mission concept for a spacecraft-borne nulling interferometer for high-resolution astronomy and the direct detection of exoplanets and assay of their environments and atmospheres. FKSI is a high angular resolution system operating in the near to midinfrared spectral region and is a scientific and technological pathfinder to the Darwin and Terrestrial Planet Finder (TPF) missions. The instrument is configured with an optical system consisting, depending on configuration, of two 0.5 - 1.0 m telescopes on a 12.5 - 20 m boom feeding a symmetric, dual Mach- Zehnder beam combiner. We report on progress on our nulling testbed including the design of an optical pathlength null-tracking control system and development of a testing regime for hollow-core fiber waveguides proposed for use in wavefront cleanup. We also report results of integrated simulation studies of the planet detection performance of FKSI and results from an in-depth control system and residual optical pathlength jitter analysis.

Barry, R. K.↗
DOE OSTI2022

Interaction of cosmological domain walls with large classical objects, like planets and satellites, and the flyby anomaly

Cosmological domain walls can be formed as a result of symmetry breaking at any epoch during the evolution of our universe. We study their interaction with a classical macroscopic object, like Earth or a satellite in Earth’s orbit. We set up an action that includes the interaction term between the massive classical object and the scalar field that the domain wall is made of. We use numerical calculations to solve the coupled equations of motion which describe the crossing between the domain wall and the classical object. Depending on the strength of the interaction, relative velocity and size, the object can be either stopped by the wall, or it can pass through it inducing deformations in the wall that cost energy. At the same time, the coupling to the scalar filed might change the object’s mass during the crossover. The fact that satellites in Earth’s orbit (or planets in Sun’s orbit) can change their mass and/or lose energy interacting with walls can be used as a new domain wall detection probe. For example, a typical velocity precision of a satellite is about 0.5 mm/s, which directly puts an upper limit on its mass change to ΔM/M ≲ 5 × 10 –17 . Alternatively, a known satellite flyby anomaly can easily be explained as an interaction with a closed domain wall. We also show that the presence of matter modifies the scalar filed potential and can locally create a bubble of the true vacuum, and thus trigger the decay of the false vacuum. For a critical bubble which is able to expand, such an interaction with the domain wall must be strong enough.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
NASA NTRSDate not supplied

Balloon Flight for NephEx: A Nephelometer for Probing Planetary Atmospheres

NephEx (Nephelometer Experiment) was successfully tested in a weather balloon flight by Raven Aerostar, North Dakota in June 2021.The flight took in-situ measurements and recorded data from launch to >20 km and during all of descent(Figure 1). The flight data successfully detected super-cirrus clouds up to altitudes of 15 km and boundary layer haze. Successful testing of this instrument has brought the instrument to TRL-5 status. NephEx is capable of making direct measurement of clouds on other planets, size of particles and their concentration.

V Jha↗
NASA NTRS1986

Astrometric Telescope Facility - Status report

The advent of the Space Station Program has provided an unexpected opportunity for the Astrometric Telescope Facility (ATF) study program by providing a potential long-duration on-orbit serviceable platform. It required a concept change for ATF from a free-flyer observatory to a Space-Station-based Observatory. The program was sent in this new direction at the start of fiscal year 1985, and program plans including study schedules and science and technical requirements are being revised and defined. The facility is designed to be versatile and capable of fulfilling the primary goal of planet detection, and to be highly useful for other astrophysics observations. Basically the ATF observing program is a long-duration plan requiring repetitive observations of single stars over a one to two decade period. These repetitive observations are needed to provide data necessary to conclusively determine the existence (or nonexistence) of planets of the Uranus and Neptune class in extrasolar planetary systems.

Nishioka, K.↗
NASA NTRS2003

Brown Dwarfs: Discovery and Detailed Studies

The grant supported my research and that of my student (Ben Lane) and post-doctoral fellow (Zapatero Osorio). We were productive as can be seen from the list of publications below. In particular, we note three firsts. Using the exquisite angular resolution provided by the AO system at Keck we were able to directly determine the masses of two objects and show that one was a brown dwarf -- the first direct determination of the mass of a brown dwarf. Next, Mr. Lane reported the first direct demonstration of pulsations of a Cepheid star (this report received attention in the popular press). Finally, Dr. Zapatero Osorio continued her work on the search for young brown dwarfs and planets in young clusters with considerable success -- namely the detection of objects with mass below 10 M_J (these can be plausibly argued to be freely floating planets). Mr. Lane graduated and is now a Pappalardo Fellow at MIT and Dr. Zapatero Osorio obtained a position back in her home country.

Kulkarni, Shrinivas R.↗
NASA NTRS1994

The detection and study of pre-planetary disks

A variety of evidence suggests that at least 50% of low-mass stars are surrounded by disks of the gas and dust similar to the nebula that surrounded the Sun before the formation of the planets. The properties of these disks may bear strongly on the way in which planetary systems form and evolve. As a result of major instrumental developments over the last decade, it is now possible to detect and study the circumstellar environments of the very young, solar-type stars in some detail, and to compare the results with theoretical models of the early solar system. For example, millimeter-wave aperture synthesis imaging provides a direct means of studying in detail the morphology, temperature and density distributions, velocity field and chemical constituents in the outer disks, while high resolution, near infrared spectroscopy probes the inner, warmer parts; the emergence of gaps in the disks, possibly reflecting the formation of planets, may be reflected in the variation of their dust continuum emission with wavelength. We review progress to date and discuss likely directions for future research.

Sargent, A. I.↗
NASA NTRS1976

Computer simulation and evaluation of edge detection algorithms and their application to automatic path selection

The construction of an autonomous roving vehicle requires the development of complex data-acquisition and processing systems, which determine the path along which the vehicle travels. Thus, a vehicle must possess algorithms which can (1) reliably detect obstacles by processing sensor data, (2) maintain a constantly updated model of its surroundings, and (3) direct its immediate actions to further a long range plan. The first function consisted of obstacle recognition. Obstacles may be identified by the use of edge detection techniques. Therefore, the Kalman Filter was implemented as part of a large scale computer simulation of the Mars Rover. The second function consisted of modeling the environment. The obstacle must be reconstructed from its edges, and the vast amount of data must be organized in a readily retrievable form. Therefore, a Terrain Modeller was developed which assembled and maintained a rectangular grid map of the planet. The third function consisted of directing the vehicle's actions.

Longendorfer, B. A.↗
NASA NTRS1979

Low-energy charged particle environment at Jupiter - A first look

Preliminary results of measurements obtained by the low energy charged particle instrument on board the Voyager 1 spacecraft during its traversal of the Jovian magnetosphere are reported. The instrument consists of the low energy particle telescope and the low energy magnetospheric particle analyzer, designed to perform measurements in the inner and outer magnetosphere respectively. Ions and electrons comprising the Jovian magnetosphere were first detected at a distance of about 600 Jupiter radii from the planet, with the first bow shock crossing at 85.6 Jupiter radii. Upon crossing the magnetopause at about 67 Jupiter radii, the flows of electrons and ions were observed to change direction from away from the planet to the corotational direction. The hot plasma near the magnetosphere boundary is comprised predominantly of protons, sulfur and oxygen. Selective particle absorption near the Io flux tube indicates some form of particle deflection by Io. Fluxes in the outbound region were found to be enhanced from 90 to 160 deg longitude, and 5- and 10-hour low energy particle flux periodicities were observed.

Krimigis, S. M.↗
NASA NTRS1984

Future observations of planetary rings from groundbased observatories and earth-orbiting satellites

Three of the outer planets of our solar system are known to possess ring systems and, among the three known systems, all have one or more components that are detectable from the vicinity of the earth. Among the more promising methods for continuing study are direct imaging and occultations, obtainable both from the ground and from earth-orbiting facilities such as Space Telescope. Relevant future observations made from the vicinity of earth are expected to provide new knowledge of the dynamical and photometric properties of these outer solar system planetary rings.

Smith, B. A.↗
NASA NTRS1973

The search for signals from extraterrestrial civilizations.

The probability that a star has a habitable planet with a communicative civilization is investigated. One approach to the search problem is to assume that the other civilization will do most of the work, which implies that the search is limited to 'supercivilizations' able to transmit detectable signals in all directions all the time. The development of an optimal search strategy is discussed together with questions of the probability of success.

Walker, J. C. G.↗
NASA NTRS2013

Direct Imaging Discovery of A Super-Jupiter Around the Late B-Type Star K And*

We present the direct imaging discovery of an extrasolar planet, or possible low-mass brown dwarf, at a projected separation of 55 plus or minus 2 AU (1."058 plus or minus 0."007) from the B9-type star K And. The planet was detected with Subaru/HiCIAO (Subaru/High Contrast Instrument for the Subaru Next Generation Adaptive Optics) during the SEEDS (Strategic Exploration of Exoplanets and Disks with Subaru Telescope/HiCIAO) survey and confirmed as a bound companion via common proper motion measurements. Observed near-infrared magnitudes of J equals 16.3 plus or minus 0.3, H equals 15.2 plus or minus 0.2, K (sub s) = 14.6 plus or minus 0.4, and L prime equals 13.12 plus or minus 0.09 indicate a temperature of approximately 1700 degrees Kelvin. The galactic kinematics of the host star are consistent with membership in the Columba Association, implying a corresponding age of 30 (exp from plus 20 to minus10) Myr. The systems age, combined with the companion photometry, points to a model-dependent companion mass approximately 12.8 times the mass of Jupiter. The host stars estimated mass of 2.4 to 2.5 times the mass of the sun places it among the most massive stars ever known to harbor an extrasolar planet or low-mass brown dwarf. While the mass of the companion is close to the deuterium burning limit, its mass ratio, orbital separation, and likely planet-like formation scenario imply that it may be best defined as a super-Jupiter with properties similar to other recently discovered companions to massive stars.

HiCIAO↗
DOE OSTI2020

First Images of the Protoplanetary Disk around PDS 201

Scattered light imaging has revealed nearly a dozen circumstellar disks around young Herbig Ae/Be stars—enabling studies of structures in the upper disk layers as potential signs of ongoing planet formation. We present the first images of the disk around the variable Herbig Ae star PDS 201 (V* V351 Ori) and an analysis of the images and spectral energy distribution through 3D Monte Carlo radiative transfer simulations and forward modeling. The disk is detected in three data sets with the Large Binocular Telescope Interferometer/Large Binocular Telescope mid-infrared camera at the Large Binocular Telescope, including direct observations in the Ks and L′ filters, and an L′ observation with the 360° vector apodizing phase plate coronagraph. The scattered light disk extends to a very large radius of ∼250 au, which places it among the largest of such disks. Exterior to the disk, we establish detection limits on substellar companions down to ∼5 M {sub Jup} at ≳1.″5 (≳500 au), assuming the Baraffe et al. models. The images show a radial gap extending to ∼0.″4 (∼140 au at a distance of 340 pc) that is also evident in the spectral energy distribution. The large gap is a possible signpost of multiple high-mass giant planets at orbital distances (∼60–100 au) that are unusually massive and widely separated compared to those of planet populations previously inferred from protoplanetary disk substructures.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS2003

State-of-the-art Instruments for Detecting Extraterrestrial Life

In the coming decades, state-of-the-art spacecraft-based instruments that can detect key components associated with life as we know it on Earth will directly search for extinct or extant extraterrestrial life in our solar system. Advances in our analytical and detection capabilities, especially those based on microscale technologies, will be important in enhancing the abilities of these instruments. Remote sensing investigations of the atmospheres of extrasolar planets could provide evidence of photosynthetic-based life outside our solar system, although less advanced life will remain undetectable by these methods. Finding evidence of extraterrestrial life would have profound consequences both with respect to our understanding of chemical and biological evolution, and whether the biochemistry on Earth is unique in the universe.

Bada, Jeffrey L.↗
NASA NTRS2018

Direct Probe of Dark Energy Interactions with a Solar System Laboratory: NASA Innovative Advanced Concepts (NIAC) - Phase 1 Final Report

In this NIAC (NASA Innovative Advanced Concepts) study, we embrace the challenge of direct detection of the galileon dark energy field in the Vainshtein model. We developed a mission concept to directly measure the galileon field using the solar system as a laboratory. The experiment scheme involves precise measurements of the trace of the total scalar force gradient tensor. A tetrahedral constellation off our spacecraft measures the "local" traces while orbiting about 1 AU (Astronomical Unit) away from the Sun and faraway from planets (Figure 1). The trace measurement is insensitive to the much stronger gravity field which satisfies the inverse square law and thus is traceless. Atomic test masses and atom interferometer measurement techniques are used as precise drag-free inertial references while laser ranging interferometers are employed to connect among atom interferometer pairs in spacecraft for the differential gradient force measurements. We conclude that such a mission is scientifically and technologically feasible. We show that a mission of 3-year measurement time would be able to provide high confidence statements (over 3 standard deviations) about the existence and strength of the cubic galileon field of the Sun. In addition, such a mission would also provide rich and diverse scientific data for testing any gravitational theory in general beyond the Newtonian gravity, hunting for ultra-light fields of dark matter, and detecting gravitational waves in the mid-frequency band between those of LIGO (Laser Interferometer Gravitational-Wave Observatory) and LISA (Laser Interferometer Space Antenna). For these reasons, we will term the mission concept Gravity Observation and Dark energy Detection Explorer in the Solar System (GODDESS).

Dark Energy↗
NASA NTRS1994

Direct imaging of planetary systems with a ground-based radio telescope array

The National Radio Astronomy Observatory's proposed Millimeter Array (MMA) will bring unprecedented sensitivity, angular resolution, and image dynamic range to the millimeter wavelength region of the spectrum. An obvious question is whether such an instrument could be used to detect planets orbiting nearby stars. The techniques of aperture synthesis imaging developed for centimeter wavelength radio arrays are capable of producing images whose dynamic ranges greatly exceed the brightness ratio of a solar-type star and a Jupiter-like planet at sub-millimeter or millimeter wavelengths. The angular resolution required to separate a star and planet at a few pc distance can be obtained with baselines of several km. The greatest challenge is sensitivity. At the highest possible observing frequencies (approximately 300 GHz for typical high, dry sites, and approximately 900 GHz from the Antarctic plateau), the proposed MMA will be unable to detect the thermal emission from a Jupiter-like planet a few pc away. An upgraded MMA operating near 300 GHz with twice the currently proposed number of antennas, a 20% fractional bandwidth, and improved receivers could detect Jupiter at 4 pc in a few months. Building such an array on the Antarctic plateau and operating at approximately 900 GHz would allow Jupiter at 4 pc to be detected in approximately one day of observing time.

Jones, Dayton L.↗
DOE OSTI2020

Predictions of the Nancy Grace Roman Space Telescope Galactic Exoplanet Survey. II. Free-floating Planet Detection Rates

The Nancy Grace Roman Space Telescope (Roman) will perform a Galactic Exoplanet Survey (RGES) to discover bound exoplanets with semimajor axes greater than 1 au using gravitational microlensing. Roman will even be sensitive to planetary-mass objects that are not gravitationally bound to any host star. Such free-floating planetary-mass objects (FFPs) will be detected as isolated microlensing events with timescales shorter than a few days. A measurement of the abundance and mass function of FFPs is a powerful diagnostic of the formation and evolution of planetary systems, as well as the physics of the formation of isolated objects via direct collapse. We show that Roman will be sensitive to FFP lenses that have masses from that of Mars (0.1 M {sub ⊕}) to gas giants (M ≳ 100 M {sub ⊕}) as isolated lensing events with timescales from a few hours to several tens of days, respectively. We investigate the impact of the detection criteria on the survey, especially in the presence of finite-source effects for low-mass lenses. The number of detections will depend on the abundance of such FFPs as a function of mass, which is at present poorly constrained. Assuming that FFPs follow the fiducial mass function of cold, bound planets adapted from Cassan et al., we estimate that Roman will detect ∼250 FFPs with masses down to that of Mars (including ∼60 with masses ≤ M {sub ⊕}). We also predict that Roman will improve the upper limits on FFP populations by at least an order of magnitude compared to currently existing constraints.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1981

The Viking seismometry

Efforts were made to determine the seismicity of Mars as well as define its internal structure by detecting vibrations generated by marsquakes and meteoroid impacts. The lack of marsquakes recognized in the Viking data made it impossible to make any direct inferences about the interior of Mars and only allowed the setting of upper bounds on the seismic activity of the planet. After obtaining more than 2100 hours worth of data during the quite periods at rates of one sample per second or higher, the Viking 2 seismometer was turned off as a consequence of a landing system failure. During the periods when adequate data were obtained, one event of possible seismic or meteoroid impact origin was recognized; however, there is a significant probability that this event was generated by a wind gust.

Lazarewicz, A. R.↗
NASA NTRS2018

Life Beyond the Solar System: Remotely Detectable Biosignatures

For the first time in human history, we will soon be able to apply to the scientific method to the question "Are We Alone?" The rapid advance of exoplanet discovery, planetary systems science, and telescope technology will soon allow scientists to search for life beyond our Solar System through direct observation of extrasolar planets. This endeavor will occur alongside searches for habitable environments and signs of life within our Solar System. While these searches are thematically related and will inform each other, they will require separate observational techniques. The search for life on exoplanets holds potential through the great diversity of worlds to be explored beyond our Solar System. However, there are also unique challenges related to the relatively limited data this search will obtain on any individual world.

Domagal-Goldman, Shawn↗