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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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS2003

Deep impact spacecraft flyby instrument pointing in the presence of a non-active impactor spacecraft

This paper deals only with the pointing error contribution due to errors in predicting the impact location and describes the acquisition of optical data of the Impactor and associated errors using the flyby instruments; the algorithm for autonomously computing a pointing correction; the expected uncertainty in predicting the impact location; the uncertainty in the flyby pointing correction, and hence the improvement in performance.

flyby deep impact mission Impactor↗
NASA NTRS2006

Deep Impact Autonomous Navigation : the trials of targeting the unknown

On July 4, 2005 at 05:44:34.2 UTC the Impactor Spacecraft (s/c) impacted comet Tempel 1 with a relative speed of 10.3 km/s capturing high-resolution images of the surface of a cometary nucleus just seconds before impact. Meanwhile, the Flyby s/c captured the impact event using both the Medium Resolution Imager (MRI) and the High Resolution Imager (HRI) and tracked the nucleus for the entire 800 sec period between impact and shield attitude transition. The objective of the Impactor s/c was to impact in an illuminated area viewable from the Flyby s/c and capture high-resolution context images of the impact site. This was accomplished by using autonomous navigation (AutoNav) algorithms and precise attitude information from the attitude determination and control subsystem (ADCS). The Flyby s/c had two primary objectives: 1) capture the impact event with the highest temporal resolution possible in order to observe the ejecta plume expansion dynamics; and 2) track the impact site for at least 800 sec to observe the crater formation and capture the highest resolution images possible of the fully developed crater. These two objectives were met by estimating the Flyby s/c trajectory relative to Tempel 1 using the same AutoNav algorithms along with precise attitude information from ADCS and independently selecting the best impact site. This paper describes the AutoNav system, what happened during the encounter with Tempel 1 and what could have happened.

impactor spacecraft↗
NASA NTRS2001

Deep Impact PPC750 Performance Report

This paper evaluates the performance of the PPC750 flight computer under a variety of typical high CPU utilization Flight Software activities.

Power PC750 PPC750 performance↗
NASA NTRS2005

Summary of Results from Analyses of Deposits of the Deep-Ocean Impact of the Eltanin Asteroid

Deposits of the late Pliocene (2.5 Ma) Eltanin impact are unique in the known geological record. The only known example of a km-sized asteroid to impact a deep-ocean (5 km) basin, is the most meterorite-rich locality known. This was discovered as an Ir anomaly in sediments from three cores collected in 1965 by the USNS Eltanin. These cores contained mm-sized shock-melted asteroid materials and unmelted meteorite fragments. Mineral chemistry of meteorite fragments, and siderophole concentrations in melt rocks, indicate that the parent asteroid was a low-metal (4\%) mesosiderite. A geological exploration of the impact in 1995 by Polarstern expedition ANT-XIV4 was near the Freeden Seamounts (57.3S, 90.5 W), and successfully collected three cores with impact deposits. Analyses showed that sediments as old as Eocene were eroded by the impact disturbance and redeposited in three distinct units. The lowermost is a chaotic assemblage of sediment fragments up to 50 cm in size. Above this is a laminated sand-rich unit that deposited as a turbulent flow, and this is overlain by a more fine-grained deposit of silts and clays that settled from a cloud of sediment suspended in the water column. Meteoritic ejecta particles were concentrated near the base of the uppermost unit, where coarse ejecta caught up with the disturbed sediment. Here we will present results from a new suite of cores collected on Polarstern expedition ANT-XVIIU5a. In 2001, the Polarstern returned to the impact area and explored a region of 80,000 sq-km., collecting at least 16 sediment cores with meteoritic ejecta. The known strewn field extends over a region 660 by 200 km. The meteoritic ejecta is most concentrated in cores on the Freeden seamounts, and in the basins to the north, where the amount of meteoritic material deposited on the ocean floor was as much as 3 g/sq-cm. These concentrations drop off to the north and the east to levels as low as approximately 0.1 g/sq-cm. We were unable to sample the impact south and west of the seamounts, as the deposit was buried beyond the reach of our 25 m piston corer. We estimate that ground zero was in the region just north, or northwest, of the seamounts. There is no evidence that the impactor penetrated the ocean floor or formed a crater. The composition of the melted ejecta is inconsistent with mixing between projectile and terrestrial materials other than seawater salts. X-ray radiographs of sediments reveal details not seen in earlier cores. The uppermost impact unit is well-preserved in several cores, found as much as 50 km from the seamounts to the east, north, and west of the seamounts, where at least 25 cm of this unit is preserved. At greater distances burrowing organisms have mixed the sediments so if this unit did exist, it was too thin to survive bioturbation. These finegrained sediments are clearly laminated, and show alternating layers of low- and high-density (meteoritic) sediments, consistent with ripple formation in an energetic flow regime. We have extracted 35 g of meteoritic melt rock and 3 g of meteorite fragments from sieved sediments. Additionally a 9 g, 2.2 cm meteorite was recovered during opening of one core. The fact that 9\% of the coarse ejecta is unmelted meteorites may be characteristic of deep-ocean impacts. This may have significance for delivery of organic matter to the early Earth by small impacts into primordial oceans, where actual meteorite fragments can survive in significant amounts. However, a large portion of the meteoritic debris is buried rapidly by the sediments disturbed by the impact.

Kyte, Frank T.↗
NASA NTRS2016

Unveiling Clues from Spacecraft Missions to Comets and Asteroids through Impact Experiments

The Deep Impact Spacecraft mission was the first to boldly face the challenge of impacting the surface of a comet, 9P/Tempel 1, to investigate surface and subsurface 'pristine' materials. The Stardust mission to Comet 81P/Wild 2 brought back an exciting surprise: shocked minerals which were likely altered during the comet's lifetime. Signatures of shock in meteorites also suggest that the violent past of the solar system has left our small bodies with signatures of impacts and collisions. These results have led to the question: How have impacts affected the evolutionary path taken by comets and asteroids, and what signatures can be observed? A future planetary mission to a near-Earth asteroid is proposing to take the next steps toward understanding small bodies through impacts. The mission would combine an ESA led AIM (Asteroid Impact Mission) with a JHU/APL led DART (Double Asteroid Redirect Mission) spacecraft to rendezvous with binary near-Earth asteroid 65803 Didymus (1996 G2). DART would impact the smaller asteroid, 'Didymoon' while AIM would characterize the impact and the larger Didymus asteroid. With these missions in mind, a suite of experiments have been conducted at the Experimental Impact Laboratory (EIL) at NASA Johnson Space Center to investigate the effects that collisions may have on comets and asteroids. With the new capability of the vertical gun to cool targets in the chamber through the use of a cold jacket fed by liquid nitrogen, the effects of target temperature have been the focus of recent studies. Mg-rich forsterite and enstatite (orthopyroxene), diopside (monoclinic pyroxene) and magnesite (Mg-rich carbonate) were impacted. Target temperatures ranged from 25 deg to -100 deg, monitored by connecting thermocouples to the target container. Impacted targets were analyzed with a Fourier Transform Infrared Spectrometer (FTIR) and Transmission Electron Microscope (TEM). Here we present the evidence for impact-induced shock in the minerals through both spectra and TEM imaging and compare with unshocked samples.

Lederer, Susan M.↗
NASA NTRS2009

Distrubtion Tolerant Network Technology Flight Validation Report: DINET

In October and November of 2008, the Jet Propulsion Laboratory installed and tested essential elements of Delay/Disruption Tolerant Networking (DTN) technology on the Deep Impact spacecraft. This experiment, called Deep Impact Network Experiment (DINET), was performed in close cooperation with the EPOXI project which has responsibility for the spacecraft. During DINET some 300 images were transmitted from the JPL nodes to the spacecraft. Then, they were automatically forwarded from the spacecraft back to the JPL nodes, exercising DTN's bundle origination, transmission, acquisition, dynamic route computation, congestion control, prioritization, custody transfer, and automatic retransmission procedures, both on the spacecraft and on the ground, over a period of 27 days. All transmitted bundles were successfully received, without corruption. The DINET experiment demonstrated DTN readiness for operational use in space missions.

networking↗
NASA NTRS2009

Distribution Tolerant Network Technology Flight Validation Report: DINET

In October and November of 2008, the Jet Propulsion Laboratory installed and tested essential elements of Delay/Disruption Tolerant Networking (DTN) technology on the Deep Impact spacecraft. This experiment, called Deep Impact Network Experiment (DINET), was performed in close cooperation with the EPOXI project which has responsibility for the spacecraft. During DINET some 300 images were transmitted from the JPL nodes to the spacecraft. Then, they were automatically forwarded from the spacecraft back to the JPL nodes, exercising DTN's bundle origination, transmission, acquisition, dynamic route computation, congestion control, prioritization, custody transfer, and automatic retransmission procedures, both on the spacecraft and on the ground, over a period of 27 days. All transmitted bundles were successfully received, without corruption. The DINET experiment demonstrated DTN readiness for operational use in space missions.

networking↗
NASA NTRS2011

Deep Space Networking Experiments on the EPOXI Spacecraft

NASA's Space Communications & Navigation Program within the Space Operations Directorate is operating a program to develop and deploy Disruption Tolerant Networking [DTN] technology for a wide variety of mission types by the end of 2011. DTN is an enabling element of the Interplanetary Internet where terrestrial networking protocols are generally unsuitable because they rely on timely and continuous end-to-end delivery of data and acknowledgments. In fall of 2008 and 2009 and 2011 the Jet Propulsion Laboratory installed and tested essential elements of DTN technology on the Deep Impact spacecraft. These experiments, called Deep Impact Network Experiment (DINET 1) were performed in close cooperation with the EPOXI project which has responsibility for the spacecraft. The DINET 1 software was installed on the backup software partition on the backup flight computer for DINET 1. For DINET 1, the spacecraft was at a distance of about 15 million miles (24 million kilometers) from Earth. During DINET 1 300 images were transmitted from the JPL nodes to the spacecraft. Then, they were automatically forwarded from the spacecraft back to the JPL nodes, exercising DTN's bundle origination, transmission, acquisition, dynamic route computation, congestion control, prioritization, custody transfer, and automatic retransmission procedures, both on the spacecraft and on the ground, over a period of 27 days. The first DINET 1 experiment successfully validated many of the essential elements of the DTN protocols. DINET 2 demonstrated: 1) additional DTN functionality, 2) automated certain tasks which were manually implemented in DINET 1 and 3) installed the ION SW on nodes outside of JPL. DINET 3 plans to: 1) upgrade the LTP convergence-layer adapter to conform to the international LTP CL specification, 2) add convergence-layer "stewardship" procedures and 3) add the BSP security elements [PIB & PCB]. This paper describes the planning and execution of the flight experiment and the validation results.

automated data communication↗
NASA NTRS2009

Disruption Tolerant Networking Flight Validation Experiment on NASA's EPOXI Mission

In October and November of 2008, the Jet Propulsion Laboratory installed and tested essential elements of Delay/Disruption Tolerant Networking (DTN) technology on the Deep Impact spacecraft. This experiment, called Deep Impact Network Experiment (DINET), was performed in close cooperation with the EPOXI project which has responsibility for the spacecraft. During DINET some 300 images were transmitted from the JPL nodes to the spacecraft. Then they were automatically forwarded from the spacecraft back to the JPL nodes, exercising DTN's bundle origination, transmission, acquisition, dynamic route computation, congestion control, prioritization, custody transfer, and automatic retransmission procedures, both on the spacecraft and on the ground, over a period of 27 days. All transmitted bundles were successfully received, without corruption. The DINET experiment demonstrated DTN readiness for operational use in space missions. This activity was part of a larger NASA space DTN development program to mature DTN to flight readiness for a wide variety of mission types by the end of 2011. This paper describes the DTN protocols, the flight demo implementation, validation metrics which were created for the experiment, and validation results.

DTN↗
NASA NTRS2012

Autonomous Navigation Performance During The Hartley 2 Comet Flyby

On November 4, 2010, the EPOXI spacecraft performed a 700-km flyby of the comet Hartley 2 as follow-on to the successful 2005 Deep Impact prime mission. EPOXI, an extended mission for the Deep Impact Flyby spacecraft, returned a wealth of visual and infrared data from Hartley 2, marking the fifth time that high-resolution images of a cometary nucleus have been captured by a spacecraft. The highest resolution science return, captured at closest approach to the comet nucleus, was enabled by use of an onboard autonomous navigation system called AutoNav. AutoNav estimates the comet-relative spacecraft trajectory using optical measurements from the Medium Resolution Imager (MRI) and provides this relative position information to the Attitude Determination and Control System (ADCS) for maintaining instrument pointing on the comet. For the EPOXI mission, AutoNav was tasked to enable continuous tracking of a smaller, more active Hartley 2, as compared to Tempel 1, through the full encounter while traveling at a higher velocity. To meet the mission goal of capturing the comet in all MRI science images, position knowledge accuracies of +/- 3.5 km (3-?) cross track and +/- 0.3 seconds (3-?) time of flight were required. A flight-code-in-the-loop Monte Carlo simulation assessed AutoNav's statistical performance under the Hartley 2 flyby dynamics and determined optimal configuration. The AutoNav performance at Hartley 2 was successful, capturing the comet in all of the MRI images. The maximum residual between observed and predicted comet locations was 20 MRI pixels, primarily influenced by the center of brightness offset from the center of mass in the observations and attitude knowledge errors. This paper discusses the Monte Carlo-based analysis that led to the final AutoNav configuration and a comparison of the predicted performance with the flyby performance.

flyby↗
NASA NTRS2010

AutoGNC Testbed

A simulation testbed architecture was developed and implemented for the integration, test, and development of a TRL-6 flight software set called Auto- GNC. The AutoGNC software will combine the TRL-9 Deep Impact AutoNAV flight software suite, the TRL-9 Virtual Machine Language (VML) executive, and the TRL-3 G-REX guidance, estimation, and control algorithms. The Auto- GNC testbed was architected to provide software interface connections among the AutoNAV and VML flight code written in C, the G-REX algorithms in MATLAB and C, stand-alone image rendering algorithms in C, and other Fortran algorithms, such as the OBIRON landmark tracking suite. The testbed architecture incorporates software components for propagating a high-fidelity truth model of the environment and the spacecraft dynamics, along with the flight software components for onboard guidance, navigation, and control (GN&C). The interface allows for the rapid integration and testing of new algorithms prior to development of the C code for implementation in flight software. This testbed is designed to test autonomous spacecraft proximity operations around small celestial bodies, moons, or other spacecraft. The software is baselined for upcoming comet and asteroid sample return missions. This architecture and testbed will provide a direct improvement upon the onboard flight software utilized for missions such as Deep Impact, Stardust, and Deep Space 1.

Carson, John M., III↗