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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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NASA NTRS2019

The Seismic Experiment for Interior Structure (SEIS): Experiment Data Distribution

The six sensors of SEIS (The Seismic Experiment for Interior Structure) [- one of three primary instruments on NASA's Mars Lander Insight] cover a broad range of the seismic bandwidth, from 0.01 hertz to 50 hertz, with possible extension to longer periods. Data are transmitted in the form of three continuous VBB (Very Broad-Band) components at 2 samples per second (sps), an estimation of the short period (SP) energy content from the SP at 1 sps, and a continuous compound VBB/SP vertical axis at 10 sps. The continuous streams are augmented by requested event data with sample rates from 20 to 100 sps. SEIS data products are downlinked from the spacecraft in raw CCSDS (Consultative Committee for Space Data Systems) packets and converted to both the Standard for the Exchange of Earthquake Data (SEED) format files and ASCII tables (GeoCSV) for analysis and archiving. Metadata are available in dataless SEED and StionXML. Time series data (waveforms) are available in miniseed and GeoCSV. Data are distributed according to FDSN (Federation of Digital Seismograph Networks - http://www.fdsn.org) formats and interfaces. Wind, pressure and temperature data from the Auxiliary Payload Sensor Suite (APSS) will also be available in SEED format, and can be used for decorrelation and diagnostic purposes on SEIS.

Pardo, Constanza↗

NASA NTRS1991

Structure and Mechanics

Artemis is a Common Lunar Lander (CLL) design for the Space Exploration Initiative (SEI). Structure factors for the CLL's primary and secondary structures are listed in tabular form. Additionally, engineering drawings of various systems, including the propulsion and landing systems, are presented.

Sanger, George↗

NASA NTRS2016

Final Mission and Navigation Design for the 2016 Mars InSight Mission

NASA’s Interior Exploration using Seismic Investigations, Geodesy, and Heat Transport (InSight) mission was scheduled to launch the next lander to Mars in March 2016 arriving to the Red Planet in the fall. Derived from the Phoenix mission which successfully landed on Mars in May 2008, the InSight Entry, Descent, and Landing system will place a lander in the Elysium Planitia region. This paper specifies the mission and navigation requirements set by the Project and how the final mission and navigation design satisfies those requirements. Background information affecting navigation including spacecraft modeling and the physical environment which influences the spacecraft motion are included. (Note from the author: The InSight launch in 2016 was suspended due to critical issues with the Seismic Experiment for Interior Structure (SEIS) instrument that could not be fixed prior to the planned launch period. This paper represents the state of the design for the 2016 mission. No attempt has been made to reflect the latest developments).

Abilleira, Fernando↗

NASA NTRS2016

Final Mission and Navigation Design for the 2016 Mars InSight Mission

Project Overview: NASA’s 12th Discovery Program mission that will place a single geophysical lander on Mars to study its deep interior using seismic (tidal, marsquake, and impact), rotational, and thermal measurements -First mission to unveil the composition, structure and thermal state of martian crust, mantle and core; Rebuild of the Phoenix flight system, upgraded with Juno/GRAIL avionics -Phoenix cruise stage: 3-axis stabilized, 3.2 square meter UTJ (Ultra Triple-Junction) solar array, X-band telecom -Phoenix aeroshell (heat shield, backshell, parachute) -Phoenix lander: radar, pulsed thrusters, legs, payload deck, 5.1 square meter UTJ solar arrays, two redundant Li-ion batteries, UHF (Ultra High Frequency)/X-band telecom -Dual string: Internally or functionally-redundant equipment; Science Payload -SEIS (Seismic Experiment for Interior Structure) / CNES (Centre National d’Etudes Spatiales); Three-axis seismometry, to measure seismic waves traveling through the interior -HP3 (Heat Flow and Physical Properties Probe) / DLR (German Aerospace Center) -Subsurface heat probe, to measure the heat flux from the interior - RISE (Rotation and Interior Structure Experiment) / JPL (Jet Propulsion Laboratory) -Radiometric geodesy, to determine precession & nutation of the planet’s rotation axis. 2016 Disclaimer: The InSight launch in 2016 was suspended due to critical issues with the Seismic Experiment for Interior Structure (SEIS) instrument that could not be fixed prior to the planned launch period. This presentation and its corresponding paper represent the state of the design for the 2016 mission. No attempt has been made to reflect the latest developments. [2018 Note: InSight (Mars Lander) was later launched and arrived on Mars on Nov. 26, 2018.]

Abilleira, F.↗

NASA NTRS1990

The Space Exploration Initiative and NASA Langley Research Center test facilities

The NASA Exploration Technology Program (ETP) will make possible the U.S. Space Exploration Initiative (SEI), and is structured according to mission thrusts that are based on technologies to be developed and tested or that will otherwise be utilized to support SEI. Twenty-seven technology projects have thus far been established, and NASA's Langley Research Center is responsible for six lead roles and four participating roles. This report briefly defines these ten Langley-assigned ETP technology projects, and it describes both existing and proposed test facilities capable of supporting the Center's responsibilities.

Mouring, John L.↗

NASA NTRS1992

A vision for planetary exploration

A vision for planetary exploration is proposed which combines historical perspective and current NASA studies with the realities of changing political climates, economic environments, and technological directions. The concepts of Strategic Implementation Architectures (SIA), Open System Infrastructure Standards (OSIS), and Minimum Service Level Infrastructure (MSLI) are presented in order to propose a structure for the SEI which allows the realization of incremental mission objectives, establishes an investment strategy that efficiently uses public resources, and encourages partnerships with the government. The SIA is a hypothetical master plan which will allow the implementation of the complete spectrum of envisioned system capabilities for planetary exploration. OSIS consists of standards for interconnection, interoperability, and administration. MSLI can be defined as the minimum level of services provided by the system that are not justified by profit or parochial motives.

Connolly, John F.↗

NASA NTRS1999

Estimation of Mass-Loss Rates from Emission Line Profiles in the UV Spectra of Cool Stars

The photon-scattering winds of cool, low-gravity stars (K-M giants and supergiants) produce absorption features in the strong chromospheric emission lines. This provides us with an opportunity to assess important parameters of the wind, including flow and turbulent velocities, the optical depth of the wind above the region of photon creation, and the star's mass-loss rate. We have used the Lamers et al. Sobolev with Exact Integration (SEI) radiative transfer code along with simple models of the outer atmospheric structure to compute synthetic line profiles for comparison with the observed line profiles. The SEI code has the advantage of being computationally fast and allows a great number of possible wind models to be examined. We therefore use it here to obtain initial first-order estimates of the wind parameters. More sophisticated, but more time-consuming and resource intensive calculations will be performed at a later date, using the SEI-deduced wind parameters as a starting point. A comparison of the profiles over a range of wind velocity laws, turbulence values, and line opacities allows us to constrain the wind parameters, and to estimate the mass-loss rates. We have applied this analysis technique (using lines of Mg II, 0 I, and Fe II) so far to four stars: the normal K5-giant alpha Tau, the hybrid K-giant gamma Dra, the K5 supergiant lambda Vel, and the M-giant gamma Cru. We present in this paper a description of the technique, including the assumptions which go into its use, an assessment of its robustness, and the results of our analysis.

Carpenter, K. G.↗

NASA NTRS1993

Risk management for the Space Exploration Initiative

Probabilistic Risk Assessment (PRA) is a quantitative engineering process that provides the analytic structure and decision-making framework for total programmatic risk management. Ideally, it is initiated in the conceptual design phase and used throughout the program life cycle. Although PRA was developed for assessment of safety, reliability, and availability risk, it has far greater application. Throughout the design phase, PRA can guide trade-off studies among system performance, safety, reliability, cost, and schedule. These studies are based on the assessment of the risk of meeting each parameter goal, with full consideration of the uncertainties. Quantitative trade-off studies are essential, but without full identification, propagation, and display of uncertainties, poor decisions may result. PRA also can focus attention on risk drivers in situations where risk is too high. For example, if safety risk is unacceptable, the PRA prioritizes the risk contributors to guide the use of resources for risk mitigation. PRA is used in the Space Exploration Initiative (SEI) Program. To meet the stringent requirements of the SEI mission, within strict budgetary constraints, the PRA structure supports informed and traceable decision-making. This paper briefly describes the SEI PRA process.

Buchbinder, Ben↗

NASA NTRS2019

InSight and SEIS on Mars: First Results After 200 Sols

Slightly less than 50 years after the deployment of Apollo 11 seismometer, and slightly more than 41 years after the operational end of the combined Apollo seismic network, seismology is back to operations in planetary science. InSight, or Interior Exploration using Seismic Investigations, Geodesy and Heat Transport, is a mission dedicated to understand the formation and evolution of terrestrial planets through the investigation of the interior structure and processes of Mars. This presentation will outline early mission results, focusing primarily on SEIS, the Seismic Experiment for Interior Structure.

Renee Weber↗

NASA NTRS1996

Wind Variability of B Supergiants: The Two-component Stellar Wind of gamma Arae - No. 2

The stellar wind of the rapidly rotating early-B supergiant, gamma Ara, is studied using time series, high-resolution IUE spectroscopy secured over approx. 6 days in 1993 March. Results are presented based on an analysis of several line species, including N(N), C(IV), Si(IV), Si(III), C(II), and Al(III). The wind of this star is grossly structured, with evidence for latitude-dependent mass loss which reflects the role of rapid rotation. Independent, co-existing time variable features are identified at low-velocity (redward of approx. -750 km/s) and at higher-speeds extending to approx. -1500 km/s. The interface between these structures is 'defined' by the appearance of a discrete absorption component which is extremely sharp (in velocity space). The central velocity of this 'Super DAC' changes only gradually, over several days, between approx. -400 and -750 km/s in most of the ions. However, its location is shifted redward by almost 400 km/s in Al(III) and C(II), indicating that the physical structure giving rise to this feature has a substantial velocity and ionization jump. Constraints on the relative ionization properties of the wind structures are discussed, together with results based on SEI line-profile-fitting methods. The overall wind activity in gamma Ara exhibits a clear ion dependence, such that low-speed features are promoted in low-ionization species, including Al(III), C(II), and Si(III). We also highlight that - in contrast to most OB stars - there are substantial differences in the epoch-to-epoch time-averaged wind profiles of gamma Ara. We interpret the results in terms of a two-component wind model for gamma Ara, with an equatorially compressed low ionization region, and a high speed, higher-ionization polar outflow. This picture is discussed in the context of the predicted bi-stability mechanism for line-driven winds in rapidly rotating early-B type stars, and the formation of compressed wind regions in rapidly rotating hot stars. The apparent absence of a substantial shift in the wind ionization mixture of gamma Ara, and the normal nature of its photospheric spectrum, suggests wind-compression as the likely dominant cause for the observed equatorial density enhancements.

Prinja, R. K.↗

NASA NTRS1992

Structural design concepts for a multimegawatt solar electric propulsion (SEP) spacecraft

As a part of the Space Exploratory Initiative (SEI), NASA-Lewis is studying Solar Electric Propulsion (SEP) spacecraft to be used as a cargo transport vehicle to Mars. Two preliminary structural design concepts are offered for SEP spacecraft: a split blanket array configuration, and a ring structure. The split blanket configuration is an expansion of the photovoltaic solar array design proposed for Space Station Freedom and consists of eight independent solar blankets stretched and supported from a central mast. The ring structural concept is a circular design with the solar blanket stretched inside a ring. This concept uses a central mast with guy wires to provide additional support to the ring. The two design concepts are presented, then compared by performing stability, normal modes, and forced response analyses for varying levels of blanket and guy wire preloads. The ring structure configuration is shown to be advantageous because it is much stiffer, more stable, and deflects less under loading than the split blanket concept.

Lawrence, Charles↗

NASA NTRS1991

Structural Design Concepts for a Multi-Megawatt Solar Electric Propulsion (SEP) Spacecraft

Lawrence, Charles↗

NASA NTRS1992

Science and application missions of the near future

A variety of missions under study for NASA at the Marshall Space Flight Center in support of space science, SEI, and the Mission to Planet Earth are discussed. These science and application payloads including the laser atmospheric wind sounder, inner magnetosphere imager, large lunar telescope, and lunar transit telescope will utilize the capabilities of the Space Station, the earth observing system, GEO, and SEI infrastructure. Attention is given to controls, astrophysics, and structures experiment in space.

De Sanctis, C. E.↗

NASA NTRS1992

A horizontal inflatable habitat for SEI

The inflatable habitat described in this paper is a horizontally-oriented cylindrical pneumatic structure. It is part of NASA's ongoing effort to study inflatables as alternative habitats for the Space Exploration Initiative. This inflatable habitat provides a living and working environment for a crew of 12. It is an 8-m diameter by 45.34-m cylinder containing 2145 cu m of volume. Two levels of living and working areas make up the 547 sq m of floor space.

Kennedy, Kriss J.↗

NASA NTRS1999

GHRS Observations of Cool, Low-Gravity Stars: The Outer Atmosphere and Wind of the Nearby K Supergiant Lambda Velorum - 5

UV spectra of lambda Velorum taken with the Goddard High Resolution Spectrograph (GHRS) on the Hubble Space Telescope are used to probe the structure of the outer atmospheric layers and wind and to estimate the mass-loss rate from this K5 lb-II supergiant. VLA radio observations at lambda = 3.6 cm are used to obtain an independent check on the wind velocity and mass-loss rate inferred from the UV observations, Parameters of the chromospheric structure are estimated from measurements of UV line widths, positions, and fluxes and from the UV continuum flux distribution. The ratios of optically thin C II] emission lines indicate a mean chromospheric electron density of log N(sub e) approximately equal 8.9 +/- 0.2 /cc. The profiles of these lines indicate a chromospheric turbulence (v(sub 0) approximately equal 25-36 km/s), which greatly exceeds that seen in either the photosphere or wind. The centroids of optically thin emission lines of Fe II and of the emission wings of self-reversed Fe II lines indicate that they are formed in plasma approximately at rest with respect to the photosphere of the star. This suggests that the acceleration of the wind occurs above the chromospheric regions in which these emission line photons are created. The UV continuum detected by the GHRS clearly traces the mean flux-formation temperature as it increases with height in the chromosphere from a well-defined temperature minimum of 3200 K up to about 4600 K. Emission seen in lines of C III] and Si III] provides evidence of material at higher than chromospheric temperatures in the outer atmosphere of this noncoronal star. The photon-scattering wind produces self-reversals in the strong chromospheric emission lines, which allow us to probe the velocity field of the wind. The velocities to which these self-absorptions extend increase with intrinsic line strength, and thus height in the wind, and therefore directly map the wind acceleration. The width and shape of these self-absorptions reflect a wind turbulence of approximately equal 9-21 km/s. We further characterize the wind by comparing the observations with synthetic profiles generated with the Lamers et al. Sobolev with Exact Integration (SEI) radiative transfer code, assuming simple models of the outer atmospheric structure. These comparisons indicate that the wind in 1994 can be described by a model with a wind acceleration parameter beta approximately 0.9, a terminal velocity of 29-33 km/s, and a mass-loss rate approximately 3 x 10(exp -9) solar M/yr. Modeling of the 3.6 cm radio flux observed in 1997 suggests a more slowly accelerating wind (higher beta) and/or a higher mass-loss rate than inferred from the UV line profiles. These differences may be due to temporal variations in the wind or from limitations in one or both of the models. The discrepancy is currently under investigation.

Carpenter, Kenneth G.↗

NASA NTRS2021

Robotics Instrument Deployment System Surface Operations for the InSight Mars Lander

This paper describes NASA’s first successful precision robotics instrument placement and release on another astronomical body since Apollo. This operations breakthrough enabled NASA’s InSight lander to detect the first known ‘marsquake’, a faint trembling of Mars’s surface on 6th April 2019, 128 Martian days after landing on Mars on the 26th November 2018. This is the first quake detected on an astronomical body other than Earth or the Moon. This paper describes the operations of the Robotics Instrument Deployment Systems (IDS) that successfully deployed the InSight science payload to the surface of Mars. The payload includes a seismometer (SEIS), Wind and Thermal Shield (WTS) and Heat Flow and Physical Properties Package (HP3), enabling scientists to perform the first comprehensive surface-based geophysical investigation of Mars’ interior structure. In addition, the paper describes the IDS planning and command sequence generation process used for the successful deployment of SEIS, WTS and HP3 on the surface of Mars. The paper concludes with recommendations based on the experience gained from InSight IDS operations. This includes identified technology gaps in the operations of in-situ manipulators for planetary exploration.

Yen, Jeng↗

NASA NTRS1991

Space transfer vehicle concepts and requirements. Volume 1: Executive summary

The objectives of the Space Transfer Vehicle (STV) Concepts and Requirements studies were to provide sensitivity data on usage, economics, and technology associated with new space transportation systems. The study was structured to utilize data on the emerging launch vehicles, the latest mission scenarios, and Space Exploration Initiative (SEI) payload manifesting and schedules, to define a flexible, high performance, cost effective, evolutionary space transportation system for NASA. Initial activities were to support the MSFC effort in the preparation of inputs to the 90 Day Report to the National Space Council (NSC). With the results of this study establishing a point-of-departure for continuing the STV studies in 1990, additional options and mission architectures were defined. The continuing studies will update and expand the parametrics, assess new cargo and manned ETO vehicles, determine impacts on the redefined Phase 0 Space Station Freedom, and to develop a design that encompasses adequate configuration flexibility to ensure compliance with on-going NASA study recommendations with major system disconnects. In terms of general requirements, the objectives of the STV system and its mission profiles will address crew safety and mission success through a failure-tolerant and forgiving design approach. These objectives were addressed through the following: engine-out capability for all mission phases; built-in-test for vehicle health monitoring to allow testing of all critical functions such as, verification of lunar landing and ascent engines before initiating the landing sequence; critical subsystems will have multiple strings for redundancy plus adequate supplies of onboard spares for removal and replacement of failed items; crew radiation protection; and trajectories that optimize lunar and Mars performance and flyby abort capabilities.

Source record↗

NASA NTRS1991

Automation and robotics for the Space Exploration Initiative: Results from Project Outreach

A total of 52 submissions were received in the Automation and Robotics (A&R) area during Project Outreach. About half of the submissions (24) contained concepts that were judged to have high utility for the Space Exploration Initiative (SEI) and were analyzed further by the robotics panel. These 24 submissions are analyzed here. Three types of robots were proposed in the high scoring submissions: structured task robots (STRs), teleoperated robots (TORs), and surface exploration robots. Several advanced TOR control interface technologies were proposed in the submissions. Many A&R concepts or potential standards were presented or alluded to by the submitters, but few specific technologies or systems were suggested.

Gonzales, D.↗