NEODyS

NEODyS, short for Near Earth Objects Dynamic Site, is an Italian scientific information service devoted to the computation and presentation of orbital and observational information about near-Earth asteroids. Rather than functioning as a conventional commercial brand, it operates as a specialist web platform for astronomers, observatories, planetary-defense researchers, and other members of the near-Earth-object community. Its central resource is a database of near-Earth asteroid orbits that is continually, and largely automatically, updated using observations from the Minor Planet Center. The service's principal public-facing function is CLOMON2, an impact-monitoring system that evaluates near-Earth asteroids over a long future interval extending to 2100. NEODyS presents the results through risk pages and object-specific impactor tables. These materials are intended to help users understand the probability and circumstances of possible future impacts, distinguish objects requiring additional observations from those that are currently unobservable or effectively lost, and identify cases where improved orbital information could materially change the assessment. Risk-list categories include special objects, currently observable objects requiring follow-up, objects that may be recoverable in the near future, lost objects with relatively brighter absolute magnitudes, and smaller objects whose estimated size makes severe ground damage less likely. Beyond impact monitoring, NEODyS provides a broad collection of orbital and observational tools. Users can retrieve ephemerides containing sky position, apparent magnitude, altitude, airmass, solar and lunar elongation, phase angle, distances, apparent motion, and sky uncertainty. Observation-prediction functions assist observers in locating an object at a specified time and assessing the uncertainty of its predicted position. The platform also supplies orbital elements, dynamical parameters, minimum orbital intersection distance analyses, proper elements, optical and radar observation information, close-approach tables, and search functions based on orbital, observational, or planetary-encounter criteria. Observatory information and links to complementary physical and orbit-visualization resources extend the service's usefulness. Technically, the system is built around a PostgreSQL database running on Linux. Orbital calculations use the OrbFit software developed by the OrbFit Consortium, and the database-processing workflow incorporates the latest available Minor Planet Center observations. This combination of automated data maintenance, numerical orbit determination, and browser-based presentation makes NEODyS an interface between specialist dynamical astronomy and operational observation planning. A major system modernization took place on 5 February 2009, when NEODyS introduced a new PHP-based web interface and moved to OrbFit 4.0, written in Fortran 95. From 2011, the service has been operated and maintained for the European Space Agency by SpaceDyS, a University of Pisa spin-off based near Pisa. SpaceDyS also provides data and scientific consultancy to the ESA Near-Earth Object Coordination Centre at ESRIN in Frascati. NEODyS therefore occupies a continuing role in the European planetary-defense information infrastructure, while remaining an open web resource rather than a consumer-facing product line.

NEODyS emerged from collaborative work in celestial mechanics, orbit determination, and near-Earth-object impact assessment. Its founding group included Andrea Milani of the University of Pisa, Steve Chesley of NASA's Jet Propulsion Laboratory, and María Eugenia San Saturio Lapeña of the University of Valladolid. The project was designed to make the results of near-Earth-asteroid dynamical calculations available through a web interface, while maintaining a database that could be refreshed as new observations became available. The service's core concept is the integration of observation data, numerical orbit computation, and public presentation. Near-Earth asteroids are observed irregularly and their predicted positions can become uncertain, particularly when an object is faint, has a short observation arc, or will not be visible again for a prolonged period. NEODyS addresses this problem by using recent Minor Planet Center observations to maintain asteroid orbits and by exposing both the underlying orbital information and practical tools for observers. Its outputs include predicted positions, uncertainty information, orbital parameters, close approaches, and analyses related to the minimum orbital intersection distance. Impact monitoring became the service's defining function through CLOMON2. The system evaluates possible future impacts and presents results in a Risk Page, where objects are organized according to their observational condition, estimated size, and practical follow-up needs. Each listed asteroid can have an impactor table containing parameters relevant to the risk assessment. This approach supports planetary-defense work by helping researchers prioritize observations and by separating potentially actionable uncertainty from cases involving small or poorly characterized objects. NEODyS also developed into a broader astronomical information portal. In addition to risk assessment, it provides ephemerides, observation predictions, dynamical and proper elements, optical and radar observation summaries, close-approach data, database searches, and information about observatories and their performance. Links or integrations with complementary resources provide physical information from the ESA Near-Earth Object Coordination Centre and orbit animation from the Jet Propulsion Laboratory's NEO Program Office. A significant modernization was completed on 5 February 2009. NEODyS adopted a PHP-based interface and moved to OrbFit version 4.0, a Fortran 95 implementation associated with the OrbFit Consortium. The change was intended to make the web layer more flexible and easier to maintain while preserving the project's numerical-astronomy foundation. The system runs on Linux with a PostgreSQL database, and its computational services can also be performed using the OrbFit software package. Since 2011, SpaceDyS has operated and maintained NEODyS for the European Space Agency. SpaceDyS is a University of Pisa spin-off based near Pisa, and it supplies data and scientific consultancy to the ESA Near-Earth Object Coordination Centre at ESRIN in Frascati. The later phase of NEODyS thus connected an academic-origin project with a specialized European planetary-defense service provider and an institutional ESA program. The service has been described as continually expanding. Planned or discussed technical directions include uncertainty estimates for quantities such as minimum orbital intersection distance and absolute magnitude, monitoring intervals that vary with orbital uncertainty, and the incorporation of nongravitational perturbations into dynamical models. These directions reflect the continuing challenge of maintaining useful predictions as observation sets, physical models, and impact-monitoring requirements develop. NEODyS remains best understood as a scientific infrastructure and data service, not as a conventional consumer brand or standalone commercial company.

• 2019

  Risk-list size and small-object classification documented

  [1]NEODySen.wikipedia.org

  The documented Risk Page contained 1,128 near-Earth objects meeting its stated probability threshold through 2100; 551 were classified as small objects based on absolute magnitude.

• 2011

  SpaceDyS assumes operation for ESA

  [1]NEODySen.wikipedia.org

  SpaceDyS began operating and maintaining NEODyS for the European Space Agency and supporting the ESA Near-Earth Object Coordination Centre.

• 2009

  Major interface and software modernization

  [1]NEODySen.wikipedia.org

  NEODyS launched a PHP-based web interface and adopted OrbFit 4.0, improving maintainability and updating its orbit-computation environment.

A specialist, research-oriented planetary-defense and near-Earth-asteroid dynamics platform combining automated orbital data maintenance with publicly accessible analytical tools.

• Impact monitoring

  CLOMON2

  NEODyS's principal impact-monitoring system. CLOMON2 evaluates possible future impacts by analyzing near-Earth-asteroid orbits over a time horizon extending to 2100. Results are presented through the Risk Page and object-specific impactor tables, supporting assessment of impact probability, observational priority, and orbital uncertainty.

• Planetary-defense risk information

  NEODyS Risk Page

  Risk information for near-Earth asteroids is organized into practical categories including special, observable, possible recovery, lost, and small objects. Individual impactor tables provide parameters used in risk assessment and follow-up planning.

• Astronomical observation tools

  Ephemerides and observation prediction

  The service supplies predicted positions and related observing quantities, including apparent brightness, altitude, airmass, solar and lunar elongation, phase angle, distances, sky motion, and positional uncertainty. Its prediction tools help observers determine where and when a near-Earth object can be searched for or followed.

• Asteroid dynamics database

  Orbital and dynamical information

  NEODyS provides orbital parameters, minimum orbital intersection distance analyses, proper elements, optical and radar observation records, and close-approach tables. Search functions allow users to query the database using orbital, observational, and planetary-encounter criteria.

• 2011

  Transfer of operational maintenance to SpaceDySStrategy

  Background

  NEODyS was developed through academic and scientific collaboration and required continuing specialized operation and maintenance.

  Action taken

  SpaceDyS began operating and maintaining the service for the European Space Agency.

  Aftermath

  NEODyS became part of the operational support environment surrounding the ESA Near-Earth Object Coordination Centre, while retaining its scientific database and web-service functions.

  Source

• 2009

  Adoption of the PHP interface and OrbFit 4.0Generation change

  Background

  The service required a more flexible web interface and an updated numerical orbit-computation environment.

  Action taken

  NEODyS introduced a PHP-based interface and switched to OrbFit 4.0.

  Aftermath

  The update made the web system easier to modify and continued the integration of NEODyS with the OrbFit computational framework.

  Source

1. 1NEODySen.wikipedia.org
2. 2NEODyS official websitenewton.spacedys.com