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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 451 records · Page 25
All sourcesNASA NTRSDOE OSTI
NASA NTRS1983

Impact of solar system exploration on theories of chemical evolution and the origin of life

The impact of solar system exploration on theories regarding chemical evolution and the origin of life is examined in detail. Major findings from missions to Mercury, Venus, the moon, Mars, Jupiter, Saturn, and Titan are reviewed and implications for prebiotic chemistry are discussed. Among the major conclusions are: prebiotic chemistry is widespread throughout the solar system and universe; chemical evolution and the origin of life are intimately associated with the origin and evolution of the solar system; the rate, direction, and extent of prebiotic chemistry is highly dependent upon planetary characteristics; and continued exploration will increase understanding of how life originated on earth and allow better estimates of the likelihood of similar processes occurring elsewhere.

Devincenzi, D. L.↗
NASA NTRS2011

Combined Structural and Trajectory Control of Variable-Geometry Planetary Entry Systems

Some of the key challenges of planetary entry are to dissipate the large kinetic energy of the entry vehicle and to land with precision. Past missions to Mars were based on unguided entry, where entry vehicles carried payloads of less than 0.6 T and landed within 100 km of the designated target. The Mars Science Laboratory (MSL) is expected to carry a mass of almost 1 T to within 20 km of the target site. Guided lifting entry is needed to meet these higher deceleration and targeting demands. If the aerodynamic characteristics of the decelerator are variable during flight, more trajectory options are possible, and can be tailored to specific mission requirements. In addition to the entry trajectory modulation, having variable aerodynamic properties will also favor maneuvering of the vehicle prior to descent. For proper supersonic parachute deployment, the vehicle needs to turn to a lower angle of attack. One approach to entry trajectory improvement and angle of attack control is to embed a variable geometry decelerator in the design of the vehicle. Variation in geometry enables the vehicle to adjust its aerodynamic performance continuously without additional fuel cost because only electric power is needed for actuating the mechanisms that control the shape change. Novel structural and control concepts have been developed that enable the decelerator to undergo variation in geometry. Changing the aerodynamic characteristics of a flight vehicle by active means can potentially provide a mechanically simple, affordable, and enabling solution for entry, descent, and landing across a wide range of mission types, sample capture and return, and reentry to Earth, Titan, Venus, or Mars. Unguided ballistic entry is not sufficient to meet this more stringent deceleration, heating, and targeting demands. Two structural concepts for implementing the cone angle variation, a segmented shell, and a corrugated shell, have been presented.

Quadrelli, Marco B.↗
NASA NTRSDate not supplied

A Multiphysics Study to Improve Specific Energy of Primary Batteries for Low Temperature Operation for Deep Space Missions

Several lander missions on the outer planets such as Europa, Enceladus, and Titan require electrical power to operate scientific and communication equipment. The traditional power generation methods, such as a photovoltaic array, are not feasible as their efficiency drops significantly at these vast distances. The novel radioisotope power systems are not practical today based on current lander designs and the effectiveness of these systems. To perform in situ science on distant planets, a high specific energy battery (>700 Wh/kg) needs to operate for about 480 hours under cold temperatures (-40C or 0C) [1]. While a primary battery such as Li-CFx can provide high specific energy at room temperature, its specific capacity decreases significantly at low temperatures. One of the causes for this drop is low ion and electrical conductivity, and slower reaction kinetics. Slower transport and facile kinetics lead to an increase in the battery’s resistance and higher voltage drops during the cell operation, thus reducing specific capacity. Both the transport and kinetics show a strong dependence on temperature. Thus, a small temperature rise can lead to an increase in the reaction rate and ion conductivity; since the temperature, cell resistance, and specific capacity are interdependent. A conventional battery model accounts for ohmic, thermodynamic, and, electrochemical, and chemical decomposition heating. The ohmic heating can be controlled by designing a resistive microstructure and varying the ratios of the active materials [2]. The kinetics can be improved by increasing the surface area, reducing the particle size, or adding a catalyst. These parameters are often optimized to achieve high specific energy at room temperatures. A similar optimization study is not available at low temperatures and for a primary (high specific energy) battery. For this presentation, we will explore the effect of geometrical, microstructural, and material properties on optimal specific capacity at low temperatures through multiphysics simulations. The ion transport resistance depends on the porosity and the tortuosity of an electrode and the separator.

M. Mehta↗
NASA NTRS2021

Overview of Dragonfly Entry Aerosciences Measurements (DrEAM)

Dragonfly Entry Aerosciences Measurements (DrEAM) is an instrumentation suite for the Dragonfly mission’s entry vehicle heat shield and backshell that satisfies NASA’s Engineering Science Investigation requirement for a New Frontiers mission. Key in-situ measurements will be made in Titan’s atmosphere for the first time. High level DrEAM project goals include the following: measure heat shield near surface and in-depth temperatures; measure backshell near surface and in-depth temperatures; measure pressure at the heat shield and backshell surface; and measure backshell radiative and total heat flux.

EDL↗
DOE OSTI2020

Cation, Anion, and Radical Isomers of C4H4N: Computational Characterization and Implications for Astrophysical and Planetary Environments

Nitrogen-containing ions and molecules in the gas phase have been detected in non-Earth environments such as dark molecular clouds and more recently in the atmosphere of Saturn's moon Titan. These molecules may serve as precursors to larger heterocyclic structures that provide the foundation of complex biological molecules. On Titan, molecules of m/z 66 have been detected by the Cassini mission, and species of the empirical formula C 4 H 4 N may contribute to this signature. We have characterized seven isomers of C 4 H 4 N in anionic, neutral radical, and cationic states using density functional theory. Structures were optimized using the range-separated hybrid ωB97X-V with the cc-pVTZ and aug-cc-pVTZ basis sets. Anionic and radical C4H4N favor cyclic structures with aromatic and quasi-aromatic electron arrangements, respectively. Interestingly, ionization from the radical surface to the cation induces significant changes in structural stability, and the global minimum for positively charged isomers is CH 2 CCHCNH + , a pseudo-linear species reminiscent of cyanoallene. Select formation pathways to these structures from Titan's existing or postulated gas-phase species, reactions that are also relevant for other astrophysical environments, are discussed. By characterizing C 4 H 4 N isomers, we have identified energetically stable anionic, radical, and cationic structures that may be present in Titan's atmosphere and dark molecular clouds.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS2000

Vertical Lift - Not Just For Terrestrial Flight

Autonomous vertical lift vehicles hold considerable potential for supporting planetary science and exploration missions. This paper discusses several technical aspects of vertical lift planetary aerial vehicles in general, and specifically addresses technical challenges and work to date examining notional vertical lift vehicles for Mars, Titan, and Venus exploration.

VERTICAL TAKEOFF AIRCRAFT↗
NASA NTRS1993

Meeting with a Majestic Giant: The Cassini Mission to Saturn

In October of 1997, a two-story-tall robotic spacecraft will begin a journey of many years to the vast and exiting realm of Saturn. With a mass of roughly 2,500 kilograms (5,510 pounds) of dry hardware and 3,000 kilograms (6,615 pounds) of propellant, it needs a boost from the Titan IV/Centaur launch vehicle and several planetary gravity assists. Both are needed if Cassini is to reach Saturn with sufficient propellant to brake into Saturn orbit and accomplish its mission: to deliver a European-built probe to the large, hazy moon Titan, and then tour the saturnian system for nearly four years. The Cassini mission has been undertaken by NASA, the European Space Agency (ESA) and the Italian Space Agency (ASI). It is named in honor of the French-Italian astronomer Jean Dominique Cassini, who discovered the prominent gap in Saturn's main rings (now called the Cassini division), as well as the icy moons Iapetus, Rhea, Tethys and Dione...

Kohlhase, C.↗
NASA NTRS1995

Robotic Planetary Science Missions Enabled with Small NTR Engine/Stage Technologies

The high specific impulse (Isp) and engine thrust-to-weight ratio of liquid hydrogen (LH2)-cooled nuclear thermal rocket (NTR) engines makes them ideal for upper stage applications to difficult robotic planetary science missions. A small 15 thousand pound force (klbf) NTR engine using a uranium-zirconium-niobium 'ternary carbide' fuel (Isp approximately 960 seconds at approximately 3025K) developed in the Commonwealth of Independent States (CIS) is examined and its use on an expendable injection stage is shown to provide major increases in payload delivered to the outer planets (Saturn, Uranus, Neptune and Pluto). Using a single 'Titan IV-class' launch vehicle, with a lift capability to low Earth orbit (LEO) of approximately 20 metric tons (t), an expendable NTR upper stage can inject two Pluto 'Fast Flyby' spacecraft (PFF/SC) plus support equipment-combined mass of approximately 508 kg--on high energy, '6.5-9.2 year' direct trajectory missions to Pluto. A conventional chemical propulsion mission would use a liquid oxygen (LOX)/LH2 'Centaur' upper stage and two solid rocket 'kick motors' to inject a single PFF/SC on the same Titan IV launch vehicle. For follow on Pluto missions, the NTR injection stage would utilize a Jupiter 'gravity assist' (JGA) maneuver to launch a LOX/liquid methane (CH4) capture stage (Isp approximately 375 seconds) and a Pluto 'orbiter' spacecraft weighing between approximately 167-312 kg. With chemical propulsion, a Pluto orbiter mission is not a viable option because c inadequate delivered mass. Using a 'standardized' NTR injection stage and the same single Titan IV launch scenario, 'direct flight' (no gravity assist) orbiter missions to Saturn, Uranus and Neptune are also enabled with transit times of 2.3, 6.6, and 12.6 years, respectively. Injected mass includes a storable, nitrogen tetroxide/monomethyl hydrazine (N2O4/MMH) capture stage (Isp approximately 330 seconds) and orbiter payloads 340 to 820% larger than that achievable using a LOX/LH2-fueled injection stage. The paper discusses NTR technology and mission characteristics, shows NTR stage and payload accommodations within the 26.2 m long Titan IV payload fairing, and discusses NTR stage performance as a function of assumed cryogenic tank technology.

Borowski, Stanley K.↗
NASA NTRS2011

Seasonal Changes in Titan's Meteorology

The Cassini Imaging Science Subsystem has observed Titan for 1/4 Titan year, and we report here the first evidence of seasonal shifts in preferred locations of tropospheric methane clouds. South \polar convective cloud activity, common in late southern summer, has become rare. North \polar and northern mid \latitude clouds appeared during the approach to the northern spring equinox in August 2009. Recent observations have shown extensive cloud systems at low latitudes. In contrast, southern mid \latitude and subtropical clouds have appeared sporadically throughout the mission, exhibiting little seasonality to date. These differences in behavior suggest that Titan s clouds, and thus its general circulation, are influenced by both the rapid temperature response of a low \thermal \inertia surface and the much longer radiative timescale of Titan s cold thick troposphere. North \polar clouds are often seen near lakes and seas, suggesting that local increases in methane concentration and/or lifting generated by surface roughness gradients may promote cloud formation. Citation

Turtle, E. P.↗
NASA NTRS2020

Aerocapture as an Option for Ice Giants Mission

Aerocapture is an atmospheric maneuver where the aerodynamic forces of the vehicle (lift and drag) are used to provide the 𝞓V needed to slow down from the approach hyperbolic trajectory to achieve the desired captured orbit around the target planet. The aeroassist capture provides a large savings in propulsion needed to change the velocity of the vehicle, since aerodynamic forces rather than propulsive systems provide the change in velocity. Aerocapture requires an integrated system level design, including thermal protection systems, actuator systems for aerodynamic modulation, and guidance and control systems that can autonomously command the change in the aeroassist forces. Although aerocapture has been proposed for many situations in the past, including Mars, Venus, Titan, Saturn, Uranus, and Neptune orbiters as well as for Earth demonstration missions, it has not been attempted on any missions. However, many studies in the past three decades that have considered aerocapture as a design option have concluded that there are large mass savings that come from using aeroassist forces rather than propulsive forces to put a spacecraft into a captured orbit. The benefits are destination dependent, but some of the largest mass savings occur for the Ice Giants planets. Due to the large hyperbolic velocities of interplanetary trajectories approaching Uranus and Neptune, large amount of propulsion must be used to put a spacecraft in science orbits around these planets. Aerocapture can reduce the propulsion needs by dissipating energy in the sizable atmospheres of Uranus and Neptune. NASA commissioned a detailed study analysis to quantify the benefits, if any, for use at Neptune. The study found that even having to provide a heat shield aerocapture could deliver 40% more payload than an all-propulsive vehicle, and also provides for a 3–4-year reduction in trip time. Mass savings are expected also at Uranus with an aerocapture mission. Additionally, more recent advances in thermal protection systems and guidance and control systems show a path to increase capabilities beyond those results. This paper will discuss the merits of including aerocapture as an option for an Ice Giants mission. The discussion will focus on the cost and mass savings of using aerocapture instead of propulsive burns for Ice Giants orbiter mission scenarios while also detailing a potential concept of operations and entry vehicle design. Finally, the talk will discuss more recent work that shows aerocapture design is possible without the development of any novel entry vehicle. Thus, aerocapture can significantly improve science capabilities for an Ice Giants mission.

Soumyo Dutta↗
NASA NTRS1994

Comparison of the lossy image data compressions for the MESUR Pathfinder and for the Huygens Titan Probe

The commercial JPEG standard complies well with the specific requirements of exploratory space missions. Therefore, JPEG has been chosen to be the baseline for a series of spaceborne image data compressions (e.g. MARS94-HRSC, -WAOSS, HUYGENS-DISR, MESUR-IMP). One S/W-implementation (IMP) and one H/W-implementation (DISR) of image data compression are presented. Details of the modifications applied to standard JPEG are outlined. Finally, a performance comparison of the two implementations is given.

Rueffer, P.↗
NASA NTRS2000

SeaWinds on QuikSCAT Mission and Early Science Results

SeaWinds on QuikSCAT (QSCAT) is a dedicated satellite remote sensing mission for measuring ocean surface wind speed and direction, using a spinning, pencil-beam Ku-band scatterometer. It is a replacement mission for NASA Scatterometer (NSCAT), which was launched on board of the Japan's Advanced Earth Observation System (ADEOS-1) in August 1996 and returned 10 months of high quality data before the mission was terminated in June, 1997 due to the failure of the ADEOS-1 spacecraft. Since the next NASA scatterometer mission, SeaWinds on ADEOS-2 (SeaWinds), will not be launched until November 2000, NASA decided to fill the data gap by launching the QSCAT mission. Furthermore, after year 2000. the potential exists for using both the QSCAT and SeaWinds to provide approximately 6 hours global coverage of the marine winds. QSCAT is currently scheduled for launch in April, 1999 from Vandenberg Air Force Base, using Titan-II launch vehicle. The purpose of this paper is to first present the mission objectives, the spacecraft and instrument design, ground receiving systems, the science data processing system, and the data products. We will then present the post-launch calibration and verification results of the QSCAT end-to-end sensor system. Finally, we present some of the key results obtained from the first two months of the mission, which include ocean surface wind measurements, ice detection and classification, global snow cover detection, and flood detection.

Tsai, Wu-Yang↗
NASA NTRS2005

A Dual-Use Ballute For Entry And Descent During Planetary Missions

An inflatable ballute system for aerocapture at the atmosphere-bearing planets and at Titan may provide significant performance benefits, compared to conventional propulsive capture and aerocapture technologies. Ballute simulations to date release the ballute at the appropriate instant and then ignore it to focus on the trajectory of the orbiter. The latest concept, which we pursue in this paper, is to employ the ballute to soft-land a small payload. Thus the same ballute can provide two uses (1) aerocapture of the orbiter and (2) soft-landing of the lander package, hence the term dual-use ballute. The dual-use ballute concept has the potential to dramatically alter the way we approach exploration of the atmosphere-bearing bodies in the Solar System. Cases investigated here include aerocapture and soft-landing at Mars, Titan and Neptune.

Medlock, Kristin L.↗
NASA NTRS1994

A First Look at Orbit Determination for the Cassini Mission, Part 2: Saturn Tour

This paper completes the presentation of the first round of orbit determination analysis accomplished as part of Cassini navigation studies. The thrust of the analysis was to characterize operational orbit determination accuracy to first order for selected phases of the mission. The previous paper, Part 1, covered early phases from inner solar system cruise through the approach to Saturn and delivery of the Huygens probe to Titan. Part 2 resumes chronologically where Part 1 left off, covering the tour phase after delivery of the Huygens probe.

Cassini mission orbit determination Saturn Titan↗
NASA NTRS1984

Titan atmospheric probe

Increased scientific interest in the structure and composition of Titan's atmosphere, clouds and surface have led to the study of mission options to the Saturnian system with the main goal of placing a probe into the atmosphere of the satellite. Two probe concepts have been studied by NASA: the first concept, a slightly modified Galileo probe capable of withstanding approximately 50 earth G during atmospheric entry heating and deceleration, would consist of a blunted 53 degree, 136-cm-diameter half-angle cone with a hemispherical afterbody, and a descent module containing scientific instruments and a parachute; the second concept, a system designed to provide in situ atmospheric measurements of Titan's organic haze layer, would consist of a probe using a 165-cm deployable graphite fabric decelerator, a 50-cm-diameter cylindrical descent module containing five instruments and a 2.5 m-diameter parachute and a 50-cm-radius spherical nose cap. Although the modified Galileo probe is feasible, its scientific drawback includes its inability to obtain in situ measurements above approximately 100 km.

Swenson, B. L.↗
NASA NTRS1991

Probing Titan's atmosphere with a stellar occultation

The 3 July, 1989 occultation of 28 Sgr by Titan is discussed. The star was readily detectable throughout the occultation, reaching a minimum normalized flux of about 0.05. The occultation probed Titan's atmosphere in a region not studied by the Voyager spacecraft. The region is important for the aerobraking of Titan entry probes, and direct information about its properties is important for the Cassini mission. Occultation data (normalized stellar flux vs universal time) is shown in chart form for NASA supported stations, along with data from a collaborating group at the Wise observatory in Israel. Strong scintillation data of the star is noticeable in the data records, and provides information on waves/turbulence in Titan's high atmosphere.

Hubbard, W. B.↗
NASA NTRS1991

CRAF/Cassini (C/C)

The Comet Rendezvous Asteroid Flyby (CRAF) is a mission to rendezvous with the comet Tempel 2 and to station-keep at the comet for a period of 2.6 years, including the comet perihelion. There is a flyby of the asteroid Mandeville prior to the arrival at Tempel 2. The Cassini is a mission to place a spacecraft in a highly elliptical orbit around the planet Saturn and deliver a probe to the surface of its satellite Titan. There is a flyby of the asteroid 1989 UR1 prior to arrival at Saturn. Coverage goals for the two missions are explained. Information is given in tabular form for frequency assignments, telemetry, command, navigation, and tracking support responsibility.

Draper, R.↗