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Barbee, Brent

Publications and source records attributed to Barbee, Brent.

16 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2016

NEA Mitigation Studies for Short Warning Time Scenarios

This talk describes current collaborative research efforts between NASA GSFC and the Department of Energy's National Nuclear Security Administration (NNSA) national labs (Lawrence Livermore, Los Alamos, and Sandia) to design systems and frameworks for robust responses to short warning time near-Earth asteroid (NEA) scenarios, in which we would have less than 10 years to respond to an NEA on its way to impact the Earth.

planetary defense↗
NASA NTRS2016

Orbital Stability Regions for Hypothetical Natural Satellites of 101955 Bennu (1999 RQ36)

The Origins, Spectral Interpretation, Resource Investigation, Security-Regolith Explorer (OSIRIS-Rex) mission will be orbiting and returning a sample from near-Earth asteroid 101955 Bennu. Ground-based observations have determined that no object greater then 15 m in diameter is orbiting Bennu. This investigation explores the possible size and stability of a natural satellite around Bennu. The focus of this research is soley on the existence of stable orbits for a natural satellite and purposefully places how the natural satellite migrated to this orbit outside the bounds of this research. Numerical simulations modeling J2, third-body dynamics and solar radiation pressue is used on a large set of initial conditions that vary in semi-major axis, inclination, longititude of periapsis and natural satellite diameter. Stable orbital initial conditions for a given natural satellite diameter must remain in orbit for more than a thousand years without escape or collision from Bennu. The data found the possible existence of natural satellites in orbit around Bennu as small as 0.75 cm. Certain mechanisms such as the modified Laplace plane, Kozai resonance and the Sun-terminator plane are explored for yielding stable orbits of a given natural satelllite.

asteroids↗
NASA NTRS2015

BILLIARDS: Baseline Instrumented Lithology Lander, Inspector and Asteroid Redirection Demonstration System

BILLIARDS Baseline Instrumented Lithology Lander, Inspector, and Asteroid Redirection Demonstration System Proposed demonstration mission for Billiard-Ball concept Select asteroid pair with natural close approach to minimize cost and complexity Primary Objectives Rendezvous with a small (10m), near Earth (alpha) asteroid Maneuver the alpha asteroid to a collision with a 100m (beta) asteroid Produce a detectable deflection or disruption of the beta asteroid Secondary objectives Contribute knowledge of asteroid composition and characteristics Contribute knowledge of small-body formation Opportunity for international collaboration

Asteroid Redirection↗
NASA NTRS2015

Asteroid Characterization Priorities for Planetary Defense

We propose a prioritized list of asteroid characterization needs for planetary defense. In particular, we consider the properties of asteroids that are of greatest interest for assessment of planetary defense options, including gravity tractors, kinetic impactors, and nuclear explosives. In addition, much of our discussion is relevant for impact assessments and subsequent emergency-response planning. Rather than intending this as a definitive answer, however, our purpose is to stimulate and focus disscussion regarding characterization needs for planetary defense, with a specific list as a starting point. A key theme is understanding the sensitivity of the outcome of an asteroid deflection or disruption effort to the asteroids physical properties.There is a range of previous work relevant to our topic, including some explicit discussions as well as many more that are implicitly relevant. We incorporate elements from such reports while extending them using our own experience and perspectives. After introducing our prioritized list, we provide further discussion on each element, with details on the relevance of each characteristic for modeling purposes, our rationale for the assigned priority, and examples of analyses that require improved characterization information. Our goal is to establish a framework that can be modified and adapted by the community for a variety of purposes, such as mission design and optimization, development of new measurement techniques, or prioritization of research efforts. The objective is to increase understanding and reduce uncertainties in the specific aspects of characterization that most benefit accurate assessments of practical techniques for planetary defense.

Miller, Paul↗
NASA NTRS2014

An Innovative Solution to NASA's NEO Impact Threat Mitigation Grand Challenge and Flight Validation Mission Architecture Development

This final technical report describes the results of a NASA Innovative Advanced Concept (NIAC) Phase 2 study entitled "An Innovative Solution to NASA's NEO Impact Threat Mitigation Grand Challenge and Flight Validation Mission Architecture Development." This NIAC Phase 2 study was conducted at the Asteroid Deflection Research Center (ADRC) of Iowa State University in 2012-2014. The study objective was to develop an innovative yet practically implementable solution to the most probable impact threat of an asteroid or comet with short warning time (less than 5 years). The technical materials contained in this final report are based on numerous technical papers, which have been previously published by the project team of the NIAC Phase 1 and 2 studies during the past three years. Those technical papers as well as a NIAC Phase 2 Executive Summary report can be downloaded from the ADRC website (www.adrc.iastate.edu).

NEO↗
NASA NTRS2014

A Class of Selenocentric Retrograde Orbits With Innovative Applications to Human Lunar Operations

Selenocentric distant retrograde orbits with radii from approx. 12,500 km to approx. 25,000 km are assessed for stability and for suitability as crewed command and control infrastructure locations in support of telerobotic lunar surface operations and interplanetary human transport. Such orbits enable consistent transits to and from Earth at virtually any time if they are coplanar with the Moon's geocentric orbit. They possess multiple attributes and applications distinct from NASA's proposed destination orbit for a redirected asteroid about 70,000 km from the Moon.

Moon↗
NASA NTRS2013

A Proposal for A Lean, Fast Mars Round-Trip Mission Architecture: Using Current Technologies for A Human Mission to Mars In The 2030s

We present a lean-minded, fast-transfer mission strategy and architecture concept for a first human mission to Mars that deliberately utilizes a current-technology-favored approach by means of introducing and quantitatively dening two pivotal parameters: 1) an end-to-end Mars mission duration of approximately one year, and 2) a deep space habitat of approximately 4050 metric tons. These parameters are identified and introduced by a 2012 deep space habitat study conducted at the NASA Johnson Space Center (JSC) that focused on a subset of recognized high-engineering-risk factors that may otherwise inhibit or encumber remote space travel to destinations such as Mars or near-Earth asteroids (NEAs). Additional constraints in the study favoring current technology and a lean-minded (very short) surface stay on Mars are shown to offer such Mars mission opportunities in the 2030s, enabled by a combination of on-orbit staging, mission element pre-positioning, and unique round-trip trajectories identied by state-of-the-art astrodynamics algorithms.

Architecture↗
NASA NTRS2013

Human Expeditions to Near-Earth Asteroids: An Update on NASA's Status and Proposed Activities for Small Body Exploration

Over the past several years, much attention has been focused on the human exploration of near-Earth asteroids (NEAs). Two independent NASA studies examined the feasibility of sending piloted missions to NEAs, and in 2009, the Augustine Commission identified NEAs as high profile destinations for human exploration missions beyond the Earth- Moon system as part of the Flexible Path. More recently the current U.S. presidential administration directed NASA to include NEAs as destinations for future human exploration with the goal of sending astronauts to a NEA in the mid to late 2020s. This directive became part of the official National Space Policy of the United States of America as of June 28, 2010. The scientific and hazard mitigation benefits, along with the programmatic and operational benefits of a human venture beyond the Earth-Moon system, make a mission to a NEA using NASA s proposed exploration systems a compelling endeavor.

Abell, Paul↗
NASA NTRS2013

Human Expeditions to Near-Earth Asteroids: Implications for Exploration, Resource Utilization, Science, and Planetary Defense

Over the past several years, much attention has been focused on human exploration of near-Earth asteroids (NEAs) and planetary defence. Two independent NASA studies examined the feasibility of sending piloted missions to NEAs, and in 2009, the Augustine Commission identified NEAs as high profile destinations for human exploration missions beyond the Earth-Moon system as part of the Flexible Path. More recently the current U.S. presidential administration directed NASA to include NEAs as destinations for future human exploration with the goal of sending astronauts to a NEA in the mid to late 2020s. This directive became part of the official National Space Policy of the United States of America as of June 28, 2010. With respect to planetary defence, in 2005 the U.S. Congress directed NASA to implement a survey program to detect, track, and characterize NEAs equal or greater than 140 m in diameter in order to access the threat from such objects to the Earth. The current goal of this survey is to achieve 90% completion of objects equal or greater than 140 m in diameter by 2020.

Abell, Paul↗
NASA NTRS2012

Finding Near-Earth Asteroid (NEA) Destinations for Human Exploration: Implications for Astrobiology

The current number of known potential NEA targets for HSF is limited to those objects whose orbital characteristics are similar to that of the Earth. This is due to the projected capabilities of the exploration systems currently under consideration and development at NASA. However, NEAs with such orbital characteristics often have viewing geometries that place them at low solar elongations and thus are difficult to detect from the vicinity of Earth. While ongoing ground-based surveys and data archives maintained by the NEO Program Observation Program Office and the Minor Planet Center (MPC) have provided a solid basis upon which to build, a more complete catalog of the NEO population is required to inform a robust and sustainable HSF exploration program. Since all the present NEO observing assets are currently confined to the vicinity of the Earth, additional effort must be made to provide capabilities for detection of additional HSF targets via assets beyond Earth orbit. A space-based NEO survey telescope located beyond the vicinity of the Earth, has considerable implications for planetary science and astrobiology. Such a telescope will provide foundational knowledge of our Solar System small body population and detect targets of interest for both the HSF and scientific communities. Data from this asset will yield basic characterization data on the NEOs observed (i.e., albedo, size determination, potential for volatiles and organics, etc.) and help down select targets for future HSF missions. Ideally, the most attractive targets from both HSF and astrobiology perspectives are those NEAs that may contain organic and volatile materials, and which could be effectively sampled at a variety of locations and depths. Presented here is an overview of four space-based survey concepts; any one of which after just a few years of operation will discover many highly accessible NEO targets suitable for robotic and human exploration. Such a space-based survey mission will reveal incredible returns for several disciplines including: exploration, in situ resource utilization, planetary defense, and science. Of particular, interest to the scientific

Landis, Rob↗
NASA NTRS2011

Why Atens Enjoy Enhanced Accessibility For Human Space Flight

In the context of human space flight (HSF), the concept of near-Earth object (NEO) accessibility is highly subjective. Whether or not a particular NEO is accessible critically depends on mass, performance, and reliability of interplanetary HSF systems yet to be designed. Such systems would certainly include propulsion and crew life support with adequate shielding from both solar flares and galactic cosmic radiation. Equally critical architecture options are relevant to NEO accessibility. These options are also far from being determined and include the number of launches supporting an HSF mission, together with whether or not consumables are to be pre-emplaced at the destination. Until the unknowns of HSF to NEOs come into clearer focus, the notion of relative accessibility is of great utility. Imagine a group of NEOs, each with nearly equal HSF merit determined from their individual characteristics relating to crew safety, scientific return, resource utilization, and planetary defense. The more accessible members of this group are more likely to be explored first. A highly accessible NEO could conceivably be deferred in favor of a less accessible HSF destination because the latter is more accessible during a programmatically desirable launch compliant mission trajectory solutions detected in association with a specific NEO. The known NEO population is then surveyed to illustrate in which regions of heliocentric semi-major axis, eccentricity, and inclination (a, e, i) space NEOs with large n values are mapped. The (a, e, i) mapping is also formatted such that membership in each of four NEO orbit classifications, as defined below, is evident. Amors have orbits everywhere superior to (outside of) Earth's. An Amor is therefore defined to have perihelion between 1.017 astronomical units (AU) and the maximum NEO value of 1.3 AU. As of 0 hrs Universal Time on 1 January 2011 (UT epoch 2011.0), Amors numbered 2855 in the Jet Propulsion Laboratory (JPL) Small-Body Database (SBDB), comprising 37.7% of known NEOs. Apollos have orbits crossing Earth's with periods greater than Earth's. An Apollo is therefore defined to have perihelion less than 1.017 AU and a greater than 1.0 AU. As of 2011.0 UT, Apollos numbered 4080 in the SBDB, comprising 53.9% of known NEOs. Atens have orbits crossing Earth's with periods less than Earth's. An Aten is therefore defined to have aphelion greater than 0.983 AU and a less than 1.0 AU. As of 2011.0 UT, Atens numbered 618 in the SBDB, comprising 8.2% of known NEOs. Atiras have orbits everywhere inferior to (inside of) Earth's. An Atira is therefore defined to have aphelion less than 0.983 AU. As of 2011.0 UT, Atiras numbered 11 in the SBDB, comprising 0.1% of known NEOs. It is no surprise that the largest n values are chiefly associated with Apollos and Atens. Because these orbits cross Earth's, distance to be covered in a given round trip mission time delta-t can be far less than is possible for Amors or Atiras . This delta-t or the sum of mission propulsive impulse magnitudes delta-v can more frequently be minimized to enhance NHATS compliance for Apollos and Atens than is generally the case for Amors and Atiras. A less intuitive trend in NHATS results is that Atens nearly outnumber the more numerous Apollos among the most compliant NEOs as measured by n. This trend is completely out of proportion to the degree Atens are represented among the known NEO population. A theory based on geocentric NEO dynamics is presented by this paper to explain why Atens enjoy inherently greater accessibility than do Apollos. Another trend evident from mapping into (a, e, i) space is the dearth of known NEOs at low e when a < 1 AU. Underrepresentation of Atens and Atiras in the NEO catalog is at least in part attributable to observing exclusively from a perspective near Earth. Generally inferior Aten and Atira orbits are rarely, if ever, in Earth's night sky. Until a comprehensive NEO survey is conducted from an appropriateegion remote from Earth, the theory developed in this paper indicates a substantial fraction of the most accessible NEOs will remain unknown. season. Such a season is really yet another undetermined HSF architecture option. A launch season's duration will likely be measured in weeks, and it will be utilized at an indeterminate point almost certainly more than a decade in the future when HSF programmatic maturity is sufficient. Furthermore, current knowledge of the NEO population relevant to HSF is far from complete. In the 100-m-diameter class of greatest interest, only a few percent of the estimated NEO population is known [2, Figure 2.4]. Therefore, any known, lost, or fictitious NEO in a highly accessible orbit is a potential HSF destination of merit. Even if lost, fictitious, small, or hazardous, such a potential target (or another in a similar orbit) may ultimately prove to be an early HSF destination when the pertinent NEO population is more thoroughly catalogued and NEO orbits are more thoroughly maintained at high accuracy. This paper first reviews methodology and pertinent results from NASA-sponsored research performed in late 2010 and dubbed NEO HSF Accessible Targets Study (NHATS, pronounced as "gnats"). A useful accessibility metric developed during this study is n, the tally of NHATS-

Barbee, Brent↗
NASA NTRS2011

Methodology and Results of the Near-Earth Object (NEO) Human Space Flight (HSF) Accessible Targets Study (NHATS)

Near-Earth Asteroids (NEAs) have been identified by the current administration as potential destinations for human explorers during the mid-2020s. While the close proximity of these objects' orbits to Earth's orbit creates a risk of highly damaging or catastrophic impacts, it also makes some of these objects particularly accessible to spacecraft departing Earth, and this presents unique opportunities for solar system science and humanity's first ventures beyond cislunar space. Planning such ambitious missions first requires the selection of potentially accessible targets from the growing population of nearly 7,800 NEAs. To accomplish this, NASA is conducting the Near-Earth Object (NEO) Human Space Flight (HSF) Accessible Targets Study (NHATS). Phase I of the NHATS was executed during September of 2010, and Phase II was completed by early March of 2011. The study is ongoing because previously undetected NEAs are being discovered constantly, which has motivated an effort to automate the analysis algorithms in order to provide continuous monitoring of NEA accessibility. The NHATS analysis process consists of a trajectory filter and a minimum maximum estimated size criterion. The trajectory filter employs the method of embedded trajectory grids to compute all possible ballistic round-trip mission trajectories to every NEA in the Jet Propulsion Laboratory (JPL) Small-Body Database (SBDB) and stores all solutions that satisfy the trajectory filter criteria. An NEA must offer at least one qualifying trajectory solution to pass the trajectory filter. The Phase II NHATS filter criteria were purposely chosen to be highly inclusive, requiring Earth departure date between January 1st, 2015 and December 31st, 2040, total round-trip flight time <= 450 days, stay time at the NEA >= 8 days, Earth departure C(sub 3) energy <= 60 km(exp 2)/s(exp 2), total mission delta-v <= 12 km/s (including an Earth departure maneuver from a 400 km altitude circular parking orbit), and a maximum atmospheric re-entry speed of 12 km/s. After determining which NEAs offer at least one trajectory solution meeting the criteria, the estimated size constraint is then imposed whereby those NEAs may only be considered NHATS- qualifying NEAs if their maximum estimated size is >= 30 m. This corresponds to an absolute magnitude H <= 26.5 with an assumed albedo p = 0:05. The following is a brief high-level summary of the Phase II study results. Of the 7,665 NEAs in the SBDB as of February 3rd, 2011, 765 NEAs passed the trajectory filter and yielded a total of 79,157,604 trajectory solutions. The trajectory solutions for each NEA are post-processed into Pork Chop Contour (PCC) plots which show total mission delta-v as a function of Earth departure date and total mission duration. Although the PCC plots necessarily compress a very multi-dimensional design space into a two-dimensional plot, they permit rapid assessment of the breadth and quality of an NEA's available Earth departure season and clearly indicate the regions of the trajectory design space which warrant further analysis and optimization. The PCC plot for the NEA with the greatest number of NHATS-qualifying trajectory solutions, 2000 SG-344, is shown. Of the 765 NEAs which passed the Phase II trajectory filter, a total of 590 NEAs also satisfied the further constraint of maximum estimated size >= 30 m. The distributions of osculating heliocentric orbital semi-major axis (a), eccentricity (e), and inclination (i), for those 590 NEAs are shown. Note that the semi-latus rectum used is equal to alpha (1-e(exp 2)). To further our understanding of round-trip trajectory accessibility dynamics, it is instructive to examine the distribution of the NHATS-Qualifying NEAs according to orbit classification. NEAs are grouped into four orbit families: Atiras (aphelion < 0.983 AU), Atens (aphelion > 0.983 AU, alpha < 1.0 AU), Apollos (perihelion < 1.017 AU, alpha > 1.0 AU), and Amors (1.017 < perihelion < 1.3 AU). Of the 765 NEAhich satisfied the NHATS trajectory criteria, none are Atiras, 193 are Atens (31% of known Atens), 456 are Apollos (11% of known Apollos), and 116 are Amors (4% of known Amors). While Apollos comprise 60% of the NEAs which pass the NHATS trajectory filter and Atens comprise only 25%, the percentages according to orbit family are perhaps more relevant. Note that only 11% of known Apollos passed the trajectory filter while 31% of known Atens passed. These simple statistics alone strongly suggest that Aten orbits possess features which tend to enhance their round-trip trajectory accessibility as compared to Apollos or Amors. This is significant because Atens' orbits cause them to spend considerable time in Earth's daytime sky, making them difficult to discover and track using ground-based observing assets. In this paper we will detail the NHATS analysis algorithms, present and analyze all NHATS results to date, and discuss aspects of HSF mission architecture design for future NEA missions.

Barbee, Brent↗