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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 NTRS2005

Entry Dispersion Analysis for the Genesis Sample Return Capsule

Genesis will be the first mission to return samples from beyond the Earth-Moon system. The spacecraft will be inserted into a halo orbit about the L1 (Sun-Earth) libration point where it will remain for two years collecting solar wind particles. Upon Earth return, the sample return capsule, which is passively controlled, will descend under parachute to Utah. The present study describes the analysis of the entry, descent, and landing scenario of the returning sample capsule. The robustness of the entry sequence is assessed through a Monte Carlo dispersion analysis where the impact of off-nominal conditions is ascertained. The dispersion results indicate that the capsule attitude excursions near peak heating and drogue chute deployment are within Genesis mission limits. Additionally, the size of the resulting 3-sigma landing ellipse is 47.8 km in downrange by 15.2 km in crossrange, which is within the Utah Test and Training Range boundaries.

Desai, Prasun N.↗
NASA NTRS2005

Salt Kinematics and InSAR

As part of a long-term attempt to learn how the climatic and tectonic signal interact to shape a steady state mountain monitored displacement of a markers in SE termination and also near the summit of a small viscous salt fountain extruding onto the Central plateau of Iran. The marker displacements relate to the first InSAR interferograms of salt extrusion (980913 to 990620) calculated Earth tides, winds, air pressures and temperatures. In the first documented staking exercise, hammered wooden stakes vertically through the surgical marl (c. 1 Ocm deep) onto the top of crystalline salt. These stakes installed in an irregular array elongate E-W along the c.50 m high cliff marking the effective SE terminus of the glacier at Qum Kuh(Centra1 Iran) ,just to the E of a NE trending river cliff about 40 m high. We merely measured the distances between pairs of stakes with known azimuth about 2 m apart to calculate sub horizontal strain in a small part of Qum Kuh. Stakes moved and micro strains for up to 46 pairs of stakes (p strain= ((lengthl-length2)/1engthl) x 10-1) was calculated for each seven stake epochs and plotted against their azimuth on simplified array maps. The data fit well the sine curves cxpected of the maximum and minimum strain ellipses. The first documented stakes located on the SE where the InSAR image show -1 1 to 0 mm pink to purple, 0 to lOmm purple to blue, and show high activity of salt in low activity area of the InSAR image (980913 to 990620).Short term micro strains of stake tie lines record anisotropic expansions due to heating and contraction due to cooling. All epochs changed between 7 to 1 17 days (990928 to000 1 16), showed 200 to 400 micro strain lengthening and shortening. The contraction and extension existed in each epoch, but the final strain was extension in E-W in Epoch land 6, contraction in E-W direction during epochs 2-3-4-5 and 7. The second pair of stakes hammered about 20 cm deep into the deep soils(more than 1 m) , near summit, where the colors change between 19 to 29mm in InSAR image(9809 13 to 990620). Additional information is included in the original abstract.

Aftabi, Pedarm↗
NASA NTRS2005

Life in the Atacama - Year 2: Geologic Reconnaissance Through Long-Range Roving and Implications on the Search for Life

The "Life in the Atacama" (LITA) project included two field trials during the 2004 field season, each of which lasted about a week. The remote science team had no prior knowledge of the local geology, and relied entirely on orbital images and rover-acquired data to make interpretations. The sites for these trials were in different locations, and are designated "Site B" and "Site C" respectively. The primary objective of the experiment is to develop and test the means to locate, characterize, and identify habitats and life remotely through long-range roving, which included field testing the rover, named Zoe. Zoe has onboard autonomous navigation for long-range roving, a plow to overturn rocks and expose near-surface rock materials, and high-resolution imaging, spectral, and fluorescence sampling capabilities. Highlights from the experiment included characterizing the geology in and near the landing ellipse, assessing pre-mission, satellite-based hypotheses, and improving the approach and procedures used by the remote and field teams for upcoming experiments through combined satellite, field-based, and microscopic perspectives and long-range roving.

Dohm, J. M.↗
NASA NTRS2005

Torque Transmission Device at Zero Leakage

In a few critical applications, mechanical transmission of power by rotation at low speed is required without leakage at an interface. Herein we examine a device that enables torque to be transmitted across a sealed environmental barrier. The barrier represents the restraint membrane through which the torque is transmitted. The power is transferred through elastic deformation of a circular tube into an elliptical cross-section. Rotation of the principle axis of the ellipse at one end results in a commensurate rotation of an elliptical cross section at the other end of the tube. This transfer requires no rigid body rotation of the tube allowing a membrane to seal one end from the other. Both computational and experimental models of the device are presented.

Hendricks, R. C.↗
NASA NTRS1994

Wind Prelaunch Mission Operations Report (MOR)

The National Aeronautics and Space Administration (NASA) Wind mission is the first mission of the Global Geospace Science (GGS) initiative. The Wind laboratory will study the properties of particles and waves in the region between the Earth and the Sun. Using the Moon s gravity to save fuel, dual lunar swing-by orbits enable the spacecraft to sample regions close to and far from the Earth. During the three year mission, Wind will pass through the bow shock of Earth's magnetosphere to begin a thorough investigation of the solar wind. Mission objectives require spacecraft measurements in two orbits: lunar swing- by ellipses out to distances of 250 Earth radii (RE) and a small orbit around the Lagrangian point L-l that remains between the Earth and the Sun. Wind will be placed into an initial orbit for approximately 2 years. It will then be maneuvered into a transition orbit and ultimately into a halo orbit at the Earth-Sun L-l point where it will operate for the remainder of its lifetime. The Wind satellite development was managed by NASA's Goddard Space Flight Center with the Martin Marietta Corporation, Astro-Space Division serving as the prime contractor. Overall programmatic direction was provided by NASA Headquarters, Office of Space Science. The spacecraft will be launched under a launch service contract with the McDonnell Douglas Corporation on a Delta II Expendable Launch Vehicle (ELV) within a November l-l4, 1994 launch window. The Wind spacecraft carries six U.S. instruments, one French instrument, and the first Russian instrument ever to fly on an American satellite. The Wind and Polar missions are the two components of the GGS Program. Wind is also the second mission of the International Solar Terrestrial Physics (ISTP) Program. The first ISTP mission, Geotail, is a joint project of the Institute of Space and Astronautical Science of Japan and NASA which launched in 1992. The Wind mission is planned to overlap Geotail by six months and Polar by one year. The Wind and Polar missions, together with the Geotail mission (launched on July 24, 1992) and supporting equatorial measurements, will provide simultaneous data to enable the study of solar wind input to the magnetosphere and key elements of the magnetospheric response: ring current energy storage, geomagnetic tail energy storage, and ionospheric energy input.

Source record↗
NASA NTRS2005

Discrete X-Ray Sources Between M81 and NGC3077

Analysis is now complete on the XMM-Newton and Chandra/HRC fields for the interaction region between M81 and NGC 3077. In addition, we have recently obtained ground-based optical data (KPNO 4-meter mosaic and CFHT 12K) for 2 regions of this field: one region near the edge of the D25 ellipse of M81 and a second region containing NGC 3077 and the furthest end of the HI bridge. Durrell et at. (private communication) find many young star clusters within the HI bridge, and we are in the process of performing the astrometric corrections to look for young stellar counterparts to the X-ray sources. We plan to present our results at the January 2006 AAS meeting in Washington, D.C., and are preparing a paper for submission to MNRAS in the near future with Co-Is M. Ward (U. Durham), T. Roberts (U. Leicester), A. Prestwich (CfA), A. Zezas (CfA), P. Durrell (Youngstown State), and Megan DeCesar (PSU).

Kilgard, Roy E.↗
NASA NTRS2006

MSL EDL Entry Guidance using the Entry Terminal Point Controller

The Mars Science Laboratory will be the first Mars mission to attempt a guided entry with the objective of safely delivering the entry vehicle to a survivable parachute deploy state within 10 km of the pre-designated landing site. The Entry Terminal Point Controller guidance algorithm is derived from the final phase Apollo Command Module guidance and, like Apollo, modulates the bank angle to control range based on deviations in range, altitude rate, and drag acceleration from a reference trajectory. For application to Mars landers which must make use of the tenuous Martian atmosphere, it is critical to balance the lift of the vehicle to minimize the range while still ensuring a safe deploy altitude. An overview of the process to generate optimized guidance settings is presented, discussing improvements made over the last four years. Performance tradeoffs between ellipse size and deploy altitude will be presented, along with imposed constraints of entry acceleration and heating. Performance sensitivities to the bank reversal deadbands, heading alignment, attitude initialization error, and atmospheric delivery errors are presented. Guidance settings for contingency operations, such as those appropriate for severe dust storm scenarios, are evaluated.

Source record↗
NASA NTRS2006

Entry, Descent, and Landing Operations Analysis for the Stardust Re-Entry Capsule

On the morning of January 15, 2006, the Stardust capsule successfully landed at the Utah Test and Training range in northwest Utah returning cometary samples from the comet Wild-2. An overview of the entry, descent, and landing (EDL) trajectory analysis that was performed for targeting during the Stardust Mission Navigation Operations Phase upon final approach to Earth is described. In addition, how the predicted landing location and the resulting overall 99 percentile landing footprint ellipse obtained from a Monte Carlo analysis changed over the final days and hours prior to entry is also presented. The navigation and EDL operations effort accurately delivered the entry capsule to the desired landing site. The final landing location was 8.1 km from the target, which was well within the allowable landing area.

Desao, Prasun N.↗
NASA NTRS2004

Mars Exploration Rover - a new standard for interplanetary navigation

The twin Mars Exploration Rovers, Spirit and Opportunity, arrived at Mars for landings respectively at Gusev Crater (on January 4, 2004) and Meridiani Planum (on January 25, 2004). During the development of the mission, the capability of the navigation system to deliver the landers within a particular accuracy played a major role in landing site selection. This process ultimately resulted in commitments to deliver each lander within a specified landing ellipse (about 70 km x 5 km) determined to be safe for landing and also judged to be scientifically interesting. Achieving atmospheric entry delivery accuracies consistent with this landing requirement necessitated significant improvements to the interplanetary navigation system used for MER. These improvements included new processes and software for orbit determination, aggressive, mission-critical use of interferometric ADOR tracking data, propulsive maneuver design, and entry, descent, and landing (EDL) trajectory simulation. Because these advances pressed the state -of -the art, innovative methods to verify the assumptions in the pre-launch covariance analyses were also developed. The actual achieved atmospheric entry accuracies for Spirit and Opportunity significantly bettered the requirements.

navigation↗
NASA NTRS2007

Candidate Landing Site for the Mars Science Laboratory: Vernal Crater, S.W. ARabia Terra

In the fall of 2009, the Mars Science Laboratory (MSL) will be launched to Mars. The purpose of this mission is to assess biologic potential and geology and to investigate planetary processes of relevance to past habitability. MSL will be able to provide visual, chemical, radiation, and environmental data with its suite of instruments [1]. In order to be selected for the MSL landing site, certain engineering requirements must be met [1] and the area should contain geologic features suggestive of past habitability, so that the overriding science goal of the mission will be attained. There are a total of 33 proposed landing sites as of the first MSL Landing Site Workshop held in Pasadena, CA from May 31st to June 2nd, 2006 [1]. There will be an opportunity to gather high resolution visual and hyperspectral data on all proposed landing sites from the now-orbiting Mars Reconnaissance Orbiter (MRO) which entered martian orbit and began its main science phase in November of 2006 [2]. The data being gathered are from: the high resolution imaging science experiment (HiRISE), the context (CTX) camera and the compact reconnaissance imaging spectrometer (CRISM) onboard the spacecraft. The footprints of these instruments are centered on a single point, and each proposer must submit these coordinates, along with the coordinates of the proposed landing ellipse. Data from these instruments, along with new MOC images and THEMIS mosaics, will be used to enhance our understanding of the geologic and engineering parameters of each site.

Paris, K. N.↗
NASA NTRS2006

Navigation and EDL for the Mars Exploration Rovers

A viewgraph presentation on Deep Space Navigation, and Entry, Decent, and Landing (EDL) for Mars Exploration Rovers is shown. The contents include: 1) JPL Spacecraft Operating across the Solar System; 2) 2003 - 2004: The Busiest Period in JPL's History; 3) Deep Space Navigation Will Enable Many of the New NASA Missions; 4) What Exactly is Navigation vs. GNC for Deep Space?; 5) Cruise and Approach: Why is Deep Space Navigation So Difficult?; 6) Project Importance of GNC: Landing Site Selection; 7) Planetary Communications and Tracking; 8) Tracking Data Types; 9) Delta Differential One-Way Range (deltaDOR); 10) All Solutions Leading up to TCM-4 Design; 11) Entry Flight Path Sensitivities; 12) MER Navigation Results; 13) Atmospheric Entry Targeting and Delivery; 14) Landing Ellipse Orientation; 15) MER Landing Site Trade Example; 16) Entry, Descent and Landing: Entry Guidance or What Things Do We NOT do for MER Landings (but we will later...); 17) Entering Martian Space 8:29 p.m. PST (ERT); 18) Entry, Descent and Landing; 19) Entry, Descent and Landing: Terminal Guidance; 20) The Challenge Going from 12,000 mph to Zero in Less Than Six Minutes; 21) Spirit Landing Location; 22) Entry, Descent and Landing: The Future; 23) Powered Descent Time-Line; and 24) Updated Sky Crane Maneuver Description. A short summary is also given on planetary guidance, navigation and control as it pertains to EDL systems

Mars Exploration Rover (MER)↗
NASA NTRS1998

Bright field illumination system

A Bright Field Illumination system for inspecting a range of characteristically different kinds of defects, depressions, and ridges in a selected material surface. The system has an illumination source placed near a first focus of an elliptical reflector. In addition, a camera facing the inspected area is placed near the illumination source and the first focus. The second focus of the elliptical reflector is located at a distance approximately twice the elliptical reflector's distance above the inspected surface. The elliptical reflector directs the light from the source onto the inspected surface. Due to the shape of the elliptical reflector, light that is specularly reflected from the inspected surface is directed into the camera is which located at the position of the reflected second focus of the ellipse. This system creates a brightly lighted background field against which damage sites appear as high contrast dark objects which can be easily detected by a person or an automated inspection system. In addition, the Bright Field Illumination system and method can be used in combination with a vision inspection system providing for multiplexed illumination and data handling of multiple kinds of surface characteristics including abrupt and gradual surface variations and differences between measured characteristics of different kinds and prior instruments.

Huber, Edward D.↗
NASA NTRS2007

Guidance Algorithms for Non-Drifting Trajectory Generation and Control in RendezVous Missions into Elliptical Orbits

Safety requirement represents one of the most critical aspect when defining the operational profile for a RendezVous mission. This requirement specially affects the design of the guidance algorithms that need to be tailored to guarantee what is normally referred to as Passive Trajectory Protection . The basic idea of passive trajectory protection is to design all the trajectory elements in an approach sequence such that if, at any point of the trajectory, thrust control ceases, the resulting free drift motion will remain collision free during a certain amount of time. This paper deals with the design and performances assessment of specific guidance algorithm addressing this issue. Firstly the problem is addressed for circular orbit using the Traveling Ellipse formulation for the relative motion. Secondly a solution for the RendezVous into a generic elliptical orbit is presented. This is based on a reduced transition matrix obtained through a description of the relative motion based on the first order variation of the orbital elements.

DiSotto, Emanuele↗
NASA NTRS2008

Entry, Descent, and Landing Operations Analysis for the Mars Phoenix Lander

The Mars Phoenix lander was launched August 4, 2007 and remained in cruise for ten months before landing in the northern plains of Mars in May 2008. The one-month Entry, Descent, and Landing (EDL) operations phase prior to entry consisted of daily analyses, meetings, and decisions necessary to determine if trajectory correction maneuvers and environmental parameter updates to the spacecraft were required. An overview of the Phoenix EDL trajectory simulation and analysis that was performed during the EDL approach and operations phase is described in detail. The evolution of the Monte Carlo statistics and footprint ellipse during the final approach phase is also provided. The EDL operations effort accurately delivered the Phoenix lander to the desired landing region on May 25, 2008.

Prince, Jill L.↗
NASA NTRS2008

Automatic Hazard Detection for Landers

Unmanned planetary landers to date have landed 'blind'; that is, without the benefit of onboard landing hazard detection and avoidance systems. This constrains landing site selection to very benign terrain,which in turn constrains the scientific agenda of missions. The state of the art Entry, Descent, and Landing (EDL) technology can land a spacecraft on Mars somewhere within a 20-100km landing ellipse.Landing ellipses are very likely to contain hazards such as craters, discontinuities, steep slopes, and large rocks, than can cause mission-fatal damage. We briefly review sensor options for landing hazard detection and identify a perception approach based on stereo vision and shadow analysis that addresses the broadest set of missions. Our approach fuses stereo vision and monocular shadow-based rock detection to maximize spacecraft safety. We summarize performance models for slope estimation and rock detection within this approach and validate those models experimentally. Instantiating our model of rock detection reliability for Mars predicts that this approach can reduce the probability of failed landing by at least a factor of 4 in any given terrain. We also describe a rock detector/mapper applied to large-high-resolution images from the Mars Reconnaissance Orbiter (MRO) for landing site characterization and selection for Mars missions.

hazard detection↗
NASA NTRS2010

Landmark Detection in Orbital Images Using Salience Histograms

NASA's planetary missions have collected, and continue to collect, massive volumes of orbital imagery. The volume is such that it is difficult to manually review all of the data and determine its significance. As a result, images are indexed and searchable by location and date but generally not by their content. A new automated method analyzes images and identifies "landmarks," or visually salient features such as gullies, craters, dust devil tracks, and the like. This technique uses a statistical measure of salience derived from information theory, so it is not associated with any specific landmark type. It identifies regions that are unusual or that stand out from their surroundings, so the resulting landmarks are context-sensitive areas that can be used to recognize the same area when it is encountered again. A machine learning classifier is used to identify the type of each discovered landmark. Using a specified window size, an intensity histogram is computed for each such window within the larger image (sliding the window across the image). Next, a salience map is computed that specifies, for each pixel, the salience of the window centered at that pixel. The salience map is thresholded to identify landmark contours (polygons) using the upper quartile of salience values. Descriptive attributes are extracted for each landmark polygon: size, perimeter, mean intensity, standard deviation of intensity, and shape features derived from an ellipse fit.

Wagstaff, Kiri L.↗
NASA NTRS2010

Fabrication and Modification of Nanoporous Silicon Particles

Silicon-based nanoporous particles as biodegradable drug carriers are advantageous in permeation, controlled release, and targeting. The use of biodegradable nanoporous silicon and silicon dioxide, with proper surface treatments, allows sustained drug release within the target site over a period of days, or even weeks, due to selective surface coating. A variety of surface treatment protocols are available for silicon-based particles to be stabilized, functionalized, or modified as required. Coated polyethylene glycol (PEG) chains showed the effective depression of both plasma protein adsorption and cell attachment to the modified surfaces, as well as the advantage of long circulating. Porous silicon particles are micromachined by lithography. Compared to the synthesis route of the nanomaterials, the advantages include: (1) the capability to make different shapes, not only spherical particles but also square, rectangular, or ellipse cross sections, etc.; (2) the capability for very precise dimension control; (3) the capacity for porosity and pore profile control; and (4) allowance of complex surface modification. The particle patterns as small as 60 nm can be fabricated using the state-of-the-art photolithography. The pores in silicon can be fabricated by exposing the silicon in an HF/ethanol solution and then subjecting the pores to an electrical current. The size and shape of the pores inside silicon can be adjusted by the doping of the silicon, electrical current application, the composition of the electrolyte solution, and etching time. The surface of the silicon particles can be modified by many means to provide targeted delivery and on-site permanence for extended release. Multiple active agents can be co-loaded into the particles. Because the surface modification of particles can be done on wafers before the mechanical release, asymmetrical surface modification is feasible. Starting from silicon wafers, a treatment, such as KOH dipping or reactive ion etching (RIE), may be applied to make the surface rough. This helps remove the nucleation layer. A protective layer is then deposited on the wafer. The protective layer, such as silicon nitride film or photoresist film, protects the wafer from electrochemical etching in an HF-based solution. A lithography technique is applied to pattern the particles onto the protective film. The undesired area of the protective film is removed, and the protective film on the back side of the wafer is also removed. Then the pattern is exposed to HF/surfactant solution, and a larger DC electrical current is applied to the wafers for a selected time. This step removes the nucleation layer. Then a DC current is applied to generate the nanopores. Next, a large electrical current is applied to generate a release layer. The particles are mechanically suspended in the solvent and collected by filtration or centrifuge.

Ferrari, Mauro↗
NASA NTRS2010

Mars Science Laboratory Entry, Descent, and Landing System Overview

In 2012, the Mars Science Laboratory (MSL) mission will pioneer the next generation of robotic Entry, Descent, and Landing (EDL) systems by delivering the largest and most capable rover to date to the surface of Mars. In addition to landing more mass than prior missions to Mars, MSL will offer access to regions of Mars that have been previously unreachable. The MSL EDL sequence is a result of a more stringent requirement set than any of its predecessors. Notable among these requirements is landing a 900 kg rover in a landing ellipse much smaller than that of any previous Mars lander. In meeting these requirements, MSL is extending the limits of the EDL technologies qualified by the Mars Viking, Mars Pathfinder, and Mars Exploration Rover missions. Thus, there are many design challenges that must be solved for the mission to be successful. Several pieces of the EDL design are technological firsts, such as guided entry and precision landing on another planet, as well as the entire Sky Crane maneuver. This paper discusses the MSL EDL architecture and discusses some of the challenges faced in delivering an unprecedented rover payload to the surface of Mars.

Mars Science Laboratory (MSL)↗