Skip to Content

Orbital Debris Program Office


Orbital Debris Engineering Models (ORDEM 3.0)

The latest version of the NASA Orbital Debris Engineering Model, ORDEM 3.0, has been released. The model is appropriate for those engineering solutions requiring knowledge and estimates of the orbital debris environment (debris spatial density, flux, etc.). ORDEM 3.0 can also be used as a benchmark for ground-based debris measurements and observations.

ORDEM 3.0 incorporates significant improvements over its predecessor, ORDEM2.0, which was released in 2001. For the first time, ORDEM includes uncertainties in the flux estimates. The model includes material density classes. It has also been extended to describe the orbital debris environment from low Earth orbit past geosynchronous orbit (100 to 40,000 km altitude).

Incorporated in ORDEM 3.0 is a large set of observational data (both in-situ and ground-based) that reflect the current debris environment. These data cover the object size range from 10 µm to 1 m. Analytical techniques (such as maximum likelihood estimation and Bayesian statistics) are employed to determine the orbit populations used to calculate population fluxes and their uncertainties. The model output lists fluxes of debris in half-decade size bins by distinct material characteristics (i.e., intact objects, high-, medium-, or low-material density objects, and NaK droplets) either by direction and velocity for an encompassing ‘igloo’ (for spacecraft) or by range bins (for a sensor beam on the Earth’s surface), depending on the user’s chosen operational mode.

The program graphical user interface (GUI), executable, data files, and an ORDEM 3.0 User’s Guide are included in the package. ORDEM 3.0 has been subjected to extensive verification and validation. Currently, ORDEM 3.0 runs on Windows XP and higher computers.

Although approved for public release, NASA regulations require that a software usage agreement must be obtained to acquire a copy of the NASA-developed software, ORDEM 3.0, MSC-25457. To begin the process, please press the "Request Now!" button in the software catalog.

ORDEM 3.0 was developed by NASA’s Orbital Debris Program Office (ODPO) located at Johnson Space Center, Houston, TX. Funding for the ODPO comes from NASA Headquarter’s Office of Safety and Mission Assurance.