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NASA NTRS2011

Large Bodies Associated with Meteoroid Streams

It is now accepted that some near-Earth objects (NEOs) may be dormant or dead comets. One strong indicator of cometary nature is the existence of an associated meteoroid stream with its consequently observed meteor showers. The complexes of NEOs which have very similar orbits and a likely common progenitor have been identified. The theoretical parameters for any meteor shower that may be associated with these complexes were calculated. As a result of a search of existing catalogues of meteor showers, activity has been observed corresponding to each of the theoretically predicted showers was found. We conclude that these asteroid-meteoroid complexes of four NEOs moving within the Piscids stream, three NEOs moving within the Iota Aquariids stream, and six new NEOs added to the Taurid complex are the result of a cometary break-up.

Badadzhanov, P. B.↗
NASA NTRS2011

A Low Risk Strategy for the Exploration of Near-Earth Objects

The impetus for asteroid exploration is scientific, political, and pragmatic. The notion of sending human explorers to asteroids is not new. Piloted missions to these primitive bodies were first discussed in the 1960s, pairing Saturn V rockets with enhanced Apollo spacecraft to explore what were then called "Earth-approaching asteroids." Two decades ago, NASA's Space Exploration Initiative (SEI) also briefly examined the possibility of visiting these small celestial bodies. Most recently, the U.S. Human Space Flight Review Committee (the second Augustine Commission) suggested that near-Earth objects (NEOs) represent a target-rich environment for exploration via the "Flexible Path" option. However, prior to seriously considering human missions to NEOs, it has become clear that we currently lack a robust catalog of human accessible targets. The majority of the NEOs identified by a study team across several NASA centers as "human-accessible" are probably too small and have orbits that are too uncertain to consider mounting piloted expeditions to these small worlds. The first step in developing such a catalog is, therefore, to complete a space-based NEO survey. The resulting catalog of candidate NEOs would then be transformed into a matrix of opportunities for robotic and human missions for the next several decades. This initial step of a space-based NEO survey first is the linchpin to laying the foundation of a low-risk architecture to venture out and explore these primitive bodies. We suggest such a minimalist framework architecture from 1) extensive ground-based and precursor spacecraft investigations (while applying operational knowledge from science-driven robotic missions), 2) astronaut servicing of spacecraft operating at geosynchronous Earth orbit to retain essential skills and experience, and 3) applying the sum of these skills, knowledge and experience to piloted missions to NEOs.

Landis, Rob R.↗
NASA NTRS2011

Modeling and Simulation for Multi-Missions Space Exploration Vehicle

Asteroids and Near-Earth Objects [NEOs] are of great interest for future space missions. The Multi-Mission Space Exploration Vehicle [MMSEV] is being considered for future Near Earth Object missions and requires detailed planning and study of its Guidance, Navigation, and Control [GNC]. A possible mission of the MMSEV to a NEO would be to navigate the spacecraft to a stationary orbit with respect to the rotating asteroid and proceed to anchor into the surface of the asteroid with robotic arms. The Dynamics and Real-Time Simulation [DARTS] laboratory develops reusable models and simulations for the design and analysis of missions. In this paper, the development of guidance and anchoring models are presented together with their role in achieving mission objectives and relationships to other parts of the simulation. One important aspect of guidance is in developing methods to represent the evolution of kinematic frames related to the tasks to be achieved by the spacecraft and its robot arms. In this paper, we compare various types of mathematical interpolation methods for position and quaternion frames. Subsequent work will be on analyzing the spacecraft guidance system with different movements of the arms. With the analyzed data, the guidance system can be adjusted to minimize the errors in performing precision maneuvers.

Multi-Mission Space Exploration Vehicle [MMSEV]↗
NASA NTRS2011

Multi-Mission Space Exploration Vehicle Concept Simulation of Operations in Proximity to a Near Earth Object

This paper details a project to simulate the dynamics of a proposed Multi-Mission Space Exploration Vehicle (MMSEV), and modeling the control of this spacecraft. A potential mission of the MMSEV would be to collect samples from a Near-Earth Object (NEO), a mission which would require the spacecraft to be able to navigate to an orbit keeping it stationary over an area of a spinning asteroid while a robotic arm interacts with the surface.

Near Earth Object (NEO)↗
NASA NTRS1997

Radar Reconnaissance of Near-Earth-Objects at the Dawn of the Next Millennium

Radar, the most powerful ground-based technique for post discovery investigation of NEO's (near-Earth objects), can contribute a great deal to their exploration as well as to identification and mitigation of hazardous objects. My intentions in this article are to review the current state of NEO radar reconnaissance, examine the imminent prospects for this work as upgraded instrumentation becomes available, and propose construction of a next-generation radar telescope that, unlike any existing radar instrument, would be optimized for, and dedicated to, NEO radar.

Ostro, Steven J.↗
NASA NTRS1997

Near-Earth Asteroid Tracking (NEAT) Program

The discoveries of near-Earth asteroids (NEA's) and comets have increased enormously over the last 10-20 years. This is a consequence in large par; of the success of programs that have systematically searched for these objects. These programs have been motivated by the relationships of NEA's to terrestrial impacts, meteorites, comets, and their relative accessibility to spacecraft missions. This paper will review the long-term Palomar Planet Crossing Asteroid Survey (PCAS) a photographic program and the current Near-Earth Asteroid Tracking (NEAT) system NASA's new electronic detection program. The primary goal of NEAT is to discover and inventory near-Earth asteroids and comets, collectively called near-Earth objects or NEO's, larger than 1 km in size. Details of the NEAT system and program results are presented and discussed.

Helin, Eleanor F.↗
NASA NTRS1996

Radar Reconnaissance of Near-Earth Objects at the Dawn of the Next Millenium

From Intro.: Radar, the most powerful groundbased technique for post-discovery investigation of NEOs, can contribute a great deal to their exploration as well as to identification and mitigation of hazardous objects. My intentions in this article are to review the current state of NEO radar reconnaissance, examine the imminent prospects for this work as upgraded instrumentation becomes available, and propose construction of a next-generation radar telescope that, unlike any existing radar instrument, would be optimized for, and dedicated to, NEO radar.

radar near-Earth objects NEO NEO radar↗
NASA NTRS2008

Near Earth Object (NEO) Mitigation Options Using Exploration Technologies

This presentation considers the use of new launch vehicles in defense against near-Earth objects, building upon expertise in launch vehicle and spacecraft design, astronomy and planetary science and missile defense. This work also seeks to demonstrate the synergy needed between architectures for human/robotic exploration initiatives and planetary defense. Three different mitigation operations were baselined for this study--nuclear standoff explosion, kinetic interceptor, and solar collector--however, these are not the only viable options. The design and predicted performance of each of these methods is discussed and compared. It is determined that the nuclear interceptor option can deflect NEOs of smaller size (100-500 m) with 2 years or more time before impact, and larger NEOs with 5 or more years warning; kinetic interceptors may be effective for deflection of asteroids up to 300-400 m but require 8-10 years warning time; and, solar collectors may be able to deflect NEOs up to 1 km if issues pertaining to long operation can be overcome. Ares I and Ares V vehicles show sufficient performance to enable the development of a near-term categorization and mitigation architecture.

Adams, Robert B.↗
NASA NTRS2003

Search for Near-Earth Objects with Small Aphelion Distances

An essential component of our ability to efficiently find NEOs at small solar elongation is a focal reducer, whose construction is being separately funded by a grant from NSF. This focal reducer will increase the field of view of the 8k CCD mosaic camera from 19 arc min to about 32 arc min at the Cassegrain focus of the University of Hawaii 2.24-m telescope. As of January, all but one of the lenses for the focal reducer were in hand. The final lens had been delayed due to problems with the availability of the rather exotic material out of which the manufacturer was to fabricate the lens. Perhaps as a result of their rush to deliver that final lens, it developed a crack during the annealing process at the manufacturer, thus they had to start over. The total delay in delivery of that last lens was nearly ten months, and therefore the focal reducer was not completed on schedule and could not be used on the telescope this semester. A postdoctoral research associate was recruited to handle the day-to-day operations. The closing date for applications was 2002 December 3 1, and seven were received. One applicant was not qualified, and two were marginal. Of the four qualified candidates, Fabrizio Bernardi stood out as being best qualified. He was a student of Andrea Carusi and had worked on the CINEOS project in Italy, which includes a component of searching for NEOs at small solar elongations.

Tholen, David J.↗
NASA NTRS2007

Near-Earth Object Survey and Deflection Analysis of Alternatives

The objectives of the George E. Brown, Jr. NEO Survey Program are to detect, track, catalogue, and characterize the physical characteristics of NEOs equal to or larger than 140 meters in diameter with a perihelion distance of less than 1.3 AU (Astronomical Units) from the Sun, achieving 90 percent completion of the survey within 15 years after enactment of the NASA Authorization Act of 2005. The Act was signed into law by President Bush on December 30, 2005. A study team, led by NASAs Office of Program Analysis and Evaluation (PA&E), conducted the analysis of alternatives with inputs from several other U.S. government agencies, international organizations, and representatives of private organizations. The team developed a range of possible options from public and private sources and then analyzed their capabilities and levels of performance including development schedules and technical risks.

Near Earth Objects (NEO)↗
NASA NTRS2011

Synergistic Activities of Near-Earth Object Exploration

U.S. President Obama stated on April 15, 2010 that the next goal for human spaceflight will be to send human beings to near-Earth asteroids by 2025. Missions to NEOs would undoubtedly provide a great deal of technical and engineering data on spacecraft operations for future human space exploration while conducting in-depth scientific examinations of these primitive objects. Information obtained from a human investigation of a NEO, together with ground-based observations and prior spacecraft investigations of asteroids and comets, will also provide a real measure of ground truth to data obtained from terrestrial meteorite collections. Major advances in the areas of geochemistry, impact history, thermal history, isotope analyses, mineralogy, space weathering, formation ages, thermal inertias, volatile content, source regions, solar system formation, etc. can be expected from human NEO missions. Samples directly returned from a primitive body would lead to the same kind of breakthroughs for understanding NEOs that the Apollo samples provided for understanding the Earth-Moon system and its formation history. In addition, robotic precursor and human exploration missions to NEOs would allow the NASA and its international partners to gain operational experience in performing complex tasks (e.g., sample collection, deployment of payloads, retrieval of payloads, etc.) with crew, robots, and spacecraft under microgravity conditions at or near the surface of a small body. This would provide an important synergy between the worldwide Science and Exploration communities, which will be crucial for development of future international deep space exploration architectures and has potential benefits for future exploration of other destinations beyond low-Earth orbit.

Abell, Paul↗
NASA NTRS2005

Continued Astrometric Follow-up Of Near-Earth Objects

As the grant periods overlapped, some of this information below will also be present on the previous final report. During the period May 1 2004 to April 30 2005, approximately 100 NEOs fainter than V = 20 were observed on separate nights from the 1.2-m telescope at Mt. Hopkins. Additionally, a few comets were targeted, including astrometric support of the Deep Impact mission by observing comet P/Tempel 1. Kyle Smalley was again employed as an independent contractor, and he was trained in use of the telescope, performed several remote observing runs on his own, and has now begun critical software support of the observing program. Code to automatically operate the telescope, given a target list, is approximately 90% done. During the first observing run scheduled in late September or early October, this code will be tested at on the telescope. It is probable that the 1.2m telescope will be run automatically all night without any interruption from the observer for anything during this time. Additional work on selecting which NEO targets to observe is progressing, with a beta-release of a simple target selection web page. Additionally, two-night objects with the potential of being NEOs have been extracted on a routine basis during this last grant cycle. These will also be added to a web page to facilitate additional astrometric follow-up.

Spahr, Timothy↗
NASA NTRS2007

A Piloted Flight to a Near-Earth Object: A Feasibility Study

This viewgraph presentation examines flight hardware elements of the Constellation Program (CxP) and the utilization of the Crew Exploration Vehicle (CEV), Evolvable Expendable Launch Vehicles (EELVs) and Ares launch vehicles for NEO missions.

Landis, Rob↗