1. What is NEODyS?
2. How NEODyS works
3. Future expansion of NEODyS
4. Credits

What is NEODyS?

Fundamentally, NEODyS provides information on Near Earth Objects with a convenient Web-based interface. It is based on a continually and (almost) automatically maintained database of near earth asteroid orbits. (Comet orbits are planned for a future expansion.) This site provides a number of services to the NEO community.

• For each NEO in our database, the results of our orbit determination are available for inspection and comparison with other sources. Everything needed by the user to verify our computations is available online, including our software.
• Our observation prediction service provides ephemeris predictions and finder charts with information on the linear or semi-linear confidence region as appropriate.
• Each object is linked to a database of known physical properties.

How NEODyS works

NEODyS is based on a Postgresql database running on a Linux system.

The database of orbits is continually and automatically maintained with the most recent Minor Planet Center observations. The orbits are computed with the OrbFit software package provided by the OrbFit Consortium. All of the computational services provided by this site can also be done with this software package.

Future expansion of NEODyS

NEODyS is continually expanding and improving. Here are a few of the things on our "To Do" list.

• Uncertainties of all the quantities provided with the orbit, e.g., MOID and absolute magnitude
• Variable time span for impact monitoring, based upon orbit uncertainty
• Inclusion of non-gravitational perturbations in the dynamic model

Credits

NEODyS is currently operated by a consortium with the following participing institutions:

Department of Mathematics , University of Pisa, Italy (in particular the Celestial Mechanics Group):

Andrea Milani Comparetti is one of the founders of NEODyS, Giovanni F. Gronchi, and Giacomo Tommei are active members.

IASF-INAF Rome, Italy:

Giovanni B. Valsecchi is one of the founders of NEODyS.

SpaceDyS srl, Cascina, Italy:

Fabrizio Bernardi, Andrea Chessa, and Alessio Del Vigna after having worked to the system for several years in their previous jobs at University of Pisa.

There are other institutions with which either we have a collaboration which is important for the quality of the NEODyS service, or have greatly contributed in the past to the development and operations of the system:

Jet Propulsion Laboratory, Pasadena (CA), USA

Steve Chesley is one of the founders of NEODyS. The NEODyS automatic information system was developed by Steve while at the University of Pisa on a NATO-sponsored postdoctoral fellowship, under the supervision of Andrea. He wrote most of the Perl code that transfers the output of the Fortran programs into the database. Steve left the University of Pisa at the end of 1999 to work at the Jet Propulsion Laboratory. In his present position of responsible for the NASA Sentry system he is still an essential collaborator, because of the requirement for technical verification of the most serious risk cases.

Department of Applied Mathematics, University of Valladolid, Spain:

María Eugenia Sansaturio and Oscar Arratia have contributed important software segments and have also operated the system for a long time.

We would like also to acknowledge the following contributions:

Hyperborea srl, Cascina, Italy:

Nicola Ronci and Raffaele Guerriero have been major contributors in the development of the original database and web interface for NEODyS. The interface has now been replaced with one based upon the free software PHP, but the basic ideas are the same.

OrbFit Consortium

The members of this group of researchers have developed the OrbFit software system. OrbFit does many things, the most important ones being orbit propagation, orbit determination, observation prediction, close approach analysis, and orbit identification. All of the orbital computations done by NEODyS, including the ones for impact monitoring, are based on library routines from this package.