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At least 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS2006

Landing and Population Hazard Analysis for Stardust Entry in Operations and Entry Planning

Stardust is a comet sample return mission that successfully returned to Earth on January 15, 2006. Stardust's targeted landing area was the Utah Test and Training Range in the Northwest corner of Utah. Requirements for the risks associated with landing were levied on Stardust by the Utah Test and Training Range and NASA. This paper describes the analysis to verify that these requirements were met and and includes calculation of debris survivability, generation of landing site selection plots, and identification of keep-out zones, as well as appropriate selection of the landing site. Operationally the risk requirements were all met for both of the GOMO-GO polls, so entry was authorized.

simulation↗
NASA NTRS2007

Reconstruction of the Stardust Entry

An overview of the reconstruction analyses performed for the Stardust capsule entry is described. The results indicate that the actual entry was very close to the pre-entry predictions. The capsule landed 8.1 km northwest of the desired target at Utah Test and Training Range. Frequency analysis on the infrared video data indicates that the aerodynamics generated for the Stardust capsule reasonably predicted the drag and static stability. Observations of the heatshield support the pre-entry simulation estimates of a small hypersonic angles-of-attack, since there is very little, if any, charring of the shoulder region or the aftbody. Through this investigation, an overall assertion can be made that all the data gathered from the Stardust entry is consistent with flight performance close to the nominal pre-entry prediction. Consequently, the design principles and methodologies utilized for the flight dynamics, aerodynamics, and aerothermodynamics analyses have been corroborated.

Desai, Prasun N.↗
NASA NTRS2009

Stardust Interstellar Preliminary Examination (ISPE)

In January 2006 the Stardust sample return capsule returned to Earth bearing the first solid samples from a primitive solar system body, C omet 81P/Wild2, and a collector dedicated to the capture and return o f contemporary interstellar dust. Both collectors were approximately 0.1m(exp 2) in area and were composed of aerogel tiles (85% of the co llecting area) and aluminum foils. The Stardust Interstellar Dust Col lector (SIDC) was exposed to the interstellar dust stream for a total exposure factor of 20 m(exp 2-) day during two periods before the co metary encounter. The Stardust Interstellar Preliminary Examination ( ISPE) is a three-year effort to characterize the collection using no ndestructive techniques. The ISPE consists of six interdependent proj ects: (1) Candidate identification through automated digital microsco py and a massively distributed, calibrated search (2) Candidate extr action and photodocumentation (3) Characterization of candidates thro ugh synchrotronbased FourierTranform Infrared Spectroscopy (FTIR), S canning XRay Fluoresence Microscopy (SXRF), and Scanning Transmission Xray Microscopy (STXM) (4) Search for and analysis of craters in f oils through FESEM scanning, Auger Spectroscopy and synchrotronbased Photoemission Electron Microscopy (PEEM) (5) Modeling of interstell ar dust transport in the solar system (6) Laboratory simulations of h ypervelocity dust impacts into the collecting media

Westphal, A. J.↗
NASA NTRS2010

Analysis of "Midnight" Tracks in the Stardust Interstellar Dust Collector: Possible Discovery of a Contemporary Interstellar Dust Grain

In January 2006, the Stardust sample return capsule returned to Earth bearing the first solid samples from a primitive solar system body, Comet 81P/Wild2, and a collector dedicated to the capture and return of contemporary interstellar dust. Both collectors were approximately 0.1m(exp 2) in area and were composed of aerogel tiles (85% of the collecting area) and aluminum foils. The Stardust Interstellar Dust Collector (SIDC) was exposed to the interstellar dust stream for a total exposure factor of 20 m(exp 2) day. The Stardust Interstellar Preliminary Examination (ISPE) is a three-year effort to characterize the collection using nondestructive techniques.

Westphal, A. J.↗
NASA NTRS2011

A New View on Interstellar Dust - High Fidelity Studies of Interstellar Dust Analogue Tracks in Stardust Flight Spare Aerogel

In 2000 and 2002 the Stardust Mission exposed aerogel collector panels for a total of about 200 days to the stream of interstellar grains sweeping through the solar system. The material was brought back to Earth in 2006. The goal of this work is the laboratory calibration of the collection process by shooting high speed [5 - 30km/s] interstellar dust (ISD) analogues onto Stardust aerogel flight spares. This enables an investigation into both the morphology of impact tracks as well as any structural and chemical modification of projectile and collector material. First results indicate a different ISD flux than previously assumed for the Stardust collection period.

Zolensky, Michael E.↗
NASA NTRS2011

FTIR Analysis of Aerogel Keystones from the Stardust Interstellar Dust Collector: Assessment of Terrestrial Organic Contamination and X-Ray Microprobe Beam Damage

The Stardust Interstellar Dust Collector (SIDC) was intended to capture and return contemporary interstellar dust. The approx.0.1 sq m collector was composed of aerogel tiles (85% of the collecting area) and aluminum foils and was exposed to the interstellar dust stream for a total exposure factor of 20 sq m day. The Stardust Interstellar Preliminary Examination (ISPE) is a consortium-based project to characterize the collection using nondestructive techniques. Sandford et al. recently assessed numerous potential sources of organic contaminants in the Stardust cometary collector. These contaminants could greatly complicate the analysis and interperetation of any organics associated with interstellar dust, particularly because signals from these particles are expected to be exceedingly small. Here, we present a summary of FTIR analyses of over 20 aerogel keystones, many of which contained candidates for interstellar dust.

Zolensky, M. E.↗
NASA NTRS2011

Four Interstellar Dust Candidates from the Stardust Interstellar Dust Collector

In January 2006, the Stardust sample return capsule returned to Earth bearing the first solid samples from a primitive solar system body, Comet 81P/Wild2, and a collector dedicated to the capture and return of contemporary interstellar dust. Both collectors were approx. 0.1 sq m in area and were composed of aerogel tiles (85% of the collecting area) and aluminum foils. The Stardust Interstellar Dust Collector (SIDC) was exposed to the interstellar dust stream for a total exposure factor of 20 sq m/day. The Stardust Interstellar Preliminary Examination (ISPE) is a consortium-based project to characterize the collection using nondestructive techniques. The goals and restrictions of the ISPE are described . A summary of analytical techniques is described.

Westphal, A. J.↗
NASA NTRS2012

Coordinated Analyses of Diverse Components in Whole Stardust Cometary Tracks

Analyses of samples returned from Comet Wild-2 by the Stardust spacecraft have resulted in a number of surprising findings that show the origins of comets are more complex than previously suspected [1]. Stardust aerogel tracks show considerable compositional diversity and the degree of impact related thermal modification and destruction is also highly variable. We are performing systematic examinations of entire Stardust tracks to discern the representative mineralogy and origins of comet Wild 2 components and to search for well preserved fine grained materials. Previously, we used ultramicrotomy to prepare sequential thin sections of entire "carrot" and "bulbous" type tracks along their axis while preserving their original shapes [2]. This technique allows us to characterize the usually well-preserved terminal particle (TP), but also any associated, fine-grained fragments that were shed along the track pathway. This report focuses on coordinated analyses of surviving indigenous cometary materials (crystalline and amorphous) along the aerogel track walls, their interaction with aerogel during collection and comparisons with their TPs. We examined the distribution of fragments throughout the track from the entrance hole to the TP.

Nakamura-Messenger, K.↗
NASA NTRS2012

Stardust-next : Lessons Learned from a Comet Flyby Mission

The Stardust-NExT (New Exploration of Tempel) mission, a follow-on to the Stardust prime mission, successfully completed a flyby of comet Tempel-1 on 2/14/11. However there were many challenges along the way, most significantly low propellant margin and detection of the comet in imagery later than antici-pated. These challenges and their ramifications forced the project to respond with flexibility and ingenuity. As a result, the flyby at an altitude of 178 km was nearly flawless, accomplishing all its science objectives. Lessons learned on Stardust-NExT may have relevance to other spacecraft missions.

Tempel 1↗
NASA NTRS2013

Post-Flight Evaluation of PICA and PICA-X - Comparisons of the Stardust SRC and Space-X Dragon 1 Forebody Heatshield Materials

Phenolic Impregnated Carbon Ablator (PICA) was developed at NASA Ames Research Center. As a thermal protection material, PICA has the advantages of being able to withstand high heat fluxes with a relatively low density. This ablative material was used as the forebody heat shield material for the Stardust sample return capsule, which re-entered the Earths atmosphere in 2006. Based on PICA, SpaceX developed a variant, PICA-X, and used it as the heat shield material for its Dragon spacecraft, which successfully orbited the Earth and re-entered the atmosphere during the COTS Demo Flight 1 in 2010. Post-flight analysis was previously performed on the Stardust PICA heat shield material. Similarly, a near-stagnation core was obtained from the post-flight Dragon 1 heat shield, which was retrieved from the Pacific Ocean. Materials testing and analyses were performed on the core to evaluate its ablation performance and post-flight properties. Comparisons between PICA and PICA-X are made where applicable. Stardust and Dragon offer rare opportunities to evaluate materials post-flight - this data is beneficial in understanding material performance and also improves modeling capabilities.

PICA-X↗
NASA NTRS2014

Final Reports of the Stardust ISPE: Seven Probable Interstellar Dust Particles

The Stardust spacecraft carried the first spaceborne collector specifically designed to capture and return a sample of contemporary interstellar dust to terrestrial laboratories for analysis [1]. The collector was exposed to the interstellar dust stream in two periods in 2000 and 2002 with a total exposure of approximately 1.8 10(exp 6) square meters sec. Approximately 85% of the collector consisted of aerogel, and the remainder consisted of Al foils. The Stardust Interstellar Preliminary Examination (ISPE) was a consortiumbased effort to characterize the collection in sufficient detail to enable future investigators to make informed sample requests. Among the questions to be answered were these: How many impacts are consistent in their characteristics with interstellar dust, with interplanetary dust, and with secondary ejecta from impacts on the spacecraft? Are the materials amorphous or crystalline? Are organics detectable? An additional goal of the ISPE was to develop or refine the techniques for preparation, analysis, and curation of these tiny samples, expected to be approximately 1 picogram or smaller, roughly three orders of magnitude smaller in mass than the samples in other small particle collections in NASA's collections - the cometary samples returned by Stardust, and the collection of Interplanetary Dust Particles collected in the stratosphere.

Allen, Carlton↗
NASA NTRS2014

Coordinated Mineralogical and Isotopic Analysis of a Cosmic Symplectite Identified in a Stardust Terminal Particle

Comet Wild-2 samples returned by the Stardust spacecraft contain a chemically diverse mixture of material, underscoring the complex nature of comets. Studies of entire Stardust aerogel tracks afford the opportunity to examine the fine-grained particle fragments distributed along the length of the track as well as the terminal particles. Previous TEM characterization of a terminal particle (TP) in track #147 revealed a symplectically intergrown iron sulfide and oxide assemblage. Mineralogically similar assemblages, known as cosmic symplectites (COS, formerly termed "new-PCP"), have only been identified in the primitive carbonaceous chondrite Acfer 094. Meteoritic COS have isotopically heavy O compositions (delta (sup 17), O-18 = 180per mille) that point to interactions with early solar system primordial water. In this study we report mineralogical and O isotopic measurements of the Wild-2 COS assemblage. Experimental: Track #147 is a "bulbous"-type track (4600 microns long) containing 7 terminal particles. The TPs were removed from the track, embedded in epoxy, and ultramicrotomed. A JEOL 2500SE 200 keV field-emission scanning-transmission electron microscope was used to obtain quantitative elemental maps and detailed mineralogical characterization. Following TEM analysis, two thin sections of TP4 (12 microns) were analyzed for O isotopes by raster ion imaging with the JSC NanoSIMS 50L. All three O isotopes were measured simultaneously using electron multipliers. San Carlos olivine grains were used as isotopic standards. Results and Discussion: The COS in the Wild-2 track #147 TP4 sample consists of symplectically intergrown pentlandite and nanocrystalline maghemite which coexists with high-Ca pyroxene with Na and Cr (kosmochlor component). This kosmochlor component could have a nebular origin and be precursors to type II chondrules in ordinary chondrites. Yet pentlandite is not a stable phase in the nebula. The COS in Acfer 094 also consists of pentlandite, but contains magnetite [4] rather than the more oxidized maghemite observed in the Wild-2 COS. The Acfer 094 COS display heavy O isotopic compositions that are the result of sulfidization and oxidation of Fe, Ni-metal grains and sulfides by O-17- and O-18-rich water in the solar nebula or possibly on the parent body. The O isotopic composition of the Wild-2 COS, however, is indistinguishable from terrestrial, indicating it was not altered by the same primordial aqueous reservoir as the Acfer 094 COS. The alteration could have occurred on the parent body by isotopically equilibrated ice. The mineralogy and petrography of Wild-2 samples suggests an incomplete or nascent hydration process. In future work we will analyze S isotopes in the track #147 TP4 COS and search for additional COS in Stardust samples.

Nguyen, A. N.↗
NASA NTRS2004

1-AU calibration activities for Stardust Earth Return

In January 2006, the Stardust spacecraft will deliver its Sample Return Capsule to the recovery site at the Utah Test and Training Range. Stardust will return dust samples from comet Wild 2 colleced in January 2004. During Earth return, the trajectory will be perturbed by small firings of the spacecraft reaction control thrusters. Calibration of these fireings is essential to ensure meeting Earth entry requirements. This paper will describe such calibrations performed between superior conjunctions when Stardust was about 1 AU from the Sun.

Williams, Ken↗
NASA NTRS2006

Maneuver Analysis and Targeting Strategy for the Stardust Re-Entry Capsule

Stardust employed biased maneuvers to limit turns and minimize execution errors. Biased maneuvers also addressed planetary protection and safety issues. Stardust utilized a fixed-direction burn for the final maneuver to match the prevailing attitude so no turns were needed. Performance of the final burn was calibrated in flight.

targeting↗
NASA NTRS2004

NASA STARDUST Sample Return Mission

This viewgraph presentation reviews the Stardust mission. The objectives of the mission is to rendezvous with the Wild 2 comet, and using a specially designed aerogel capture some of the cometary material, and then return a capsule with the material to Earth. Other objectives are to provide images of the comet, and capture interstellar dust. There is a description of the aerogel, the trajectory, and views of the Stardust Sample Return Capsule (SRC), Cometary and Interstellar Dust Analyzer (CIDA) instrument, and the JPL designed camera. Also included is a timeline of the projected release of data to the Planetary Data System.

Wild 2↗
NASA NTRS2004

Stardust Encounters Comet 81P/Wild 2

Stardust successfully encountered comet 81P/Wild 2 on 2 January 2004 at a distance of 236.4 +/- 1 km. All encounter investigations acquired valuable new and surprising findings. The time-of-flight spectrometer registered 29 spectra during flyby and measured the first negative ion mass spectra of cometary particles. The dust detectors recorded particles over a broad mass range, 10(exp -11) to 10(exp -4) g. Unexpectedly, the dust distribution along Stardust's flight path was far from uniform, but instead occurred in short 'bursts', suggesting in-flight breakup of fragments ejected from the nucleus. High-resolution, stunning images of the Wild 2 surface show a diverse and complex variety of landforms not seen from comets 1P/Halley and 19P/Borrelly or icy satellites of the outer solar system. Longer-exposure images reveal large numbers of jets projected nearly around the entire perimeter of the nucleus, many of which appear to be highly collimated. A triaxial ellipsoidal fit of the Wild 2 nucleus images yields the principal nucleus radii of 1.65 X 2.00 X2.75 km (+/- 0.05 km). The orientations and source locations on the nucleus surface of 20 highly collimated and partially overlapping jets have been traced. There is every indication that the expected samples were successfully collected from the Wild 2 coma and are poised for a return to Earth on 15 January 2006.

Stardust mission↗
NASA NTRS2006

Interfacing with USSTRATCOM and UTTR during Stardust Earth Return

The Stardust Sample Return Capsule separated from the main spacecraft four hours prior to atmospheric entry. Between this time and the time at which the SRC touched down at the Utah Test and Training Range, two organizations external to JPL were involved in tracking the Sample Return Capsule. Orbit determination for the Stardust spacecraft during deep space cruise, the encounters of asteroid Annefrank and comet Wild 2, and the final approach to Earth used X-band radio metric Doppler and range data obtained through the Deep Space Network. The SRC lacked the electronics needed for coherently transponded radio metric tracking, so the DSN was not able to track the SRC after it separated from the main spacecraft. Although the expected delivery accuracy at atmospheric entry was well within the capability needed to target the SRC to the desired ground location, it was still desirable to obtain direct knowledge of the SRC trajectory in case of anomalies. For this reason U.S. Strategic Command was engaged to track the SRC between separation and atmospheric entry. Once the SRC entered the atmosphere, ground sensors at UTTR were tasked to acquire the descending SRC and maintain track during the descent in order to determine the landing location, to which the ground recovery team was then directed. This paper discusses organizational interfaces, data products, and delivery schedules, and the actual tracking operations are described.

Utah Test and Training Range (UTTR)↗
NASA NTRS2011

Navigating Stardust-NEXT: The Road to Tempel 1

The Stardust-NExT (New Exploration of Tempel) mission, a follow-on to the Stardust prime mission, successfully completed a flyby of comet Tempel-1 on 2/14/11. However there were many challenges along the way in navigating this mission to its successful conclusion, most significantly low propellant margin and detection of the comet in imagery later than anticipated. These challenges and their ramifications forced the navigation team and the project to respond with flexibility and ingenuity. As a result, the resulting flyby at an altitude of 178 km was nearly flawless, accomplishing all its science objectives.

flyby↗