The major features of PREDICT Version 2.1.x include:

* Fully year 2000 compliant.

* Designed under the Linux operating system to permit operation on a
  wide and expanding variety of hardware platforms supported by the
  Linux OS.  Supported platforms range from palmtops to supercomputers
  (including 32-bit PCs (80386s or better) and Macintosh PowerPCs).

* Open source licensing allows anyone to contribute new features to
  the program while forever keeping the software, and any derivative
  works, non-proprietary and freely available.

* A *FAST* orbital prediction mode that predicts in advance passes of
  satellites, providing dates, times, coordinates, slant range distances,
  and sunlight and optical visibility information.  Predictions are
  displayed in tabular form and may be saved to a log file for later
  reference, printing, or parsing by other programs.

* An optical visual orbital prediction mode that displays satellite
  passes that may be optically visible to the groundstation.

* A solar illumination prediction mode that calculates how much time
  a satellite will spend in sunlight per day.

* A real-time tracking mode that provides dynamic information such as
  sub-satellite point, groundstation azimuth and elevation headings,
  Doppler shift, path loss, slant range, orbital altitude, orbital velocity,
  footprint diameter, orbital phase, the time and date of the next AOS
  (or LOS of the current pass), orbit number, and sunlight and visibility
  information for a single satellite, while providing live azimuth and
  elevation headings for both the sun and moon.

* A multi-tracking mode that provides sub-satellite point, azimuth and
  elevation headings, sunlight and visibility, and slant range distance
  information for all 24 satellites in the program's current database
  on a real-time basis.  Azimuth and elevation headings for the sun and
  moon are also provided, as a well as a listing of the AOS dates and
  times for the next three satellites expected to come into range of
  the groundstation.

* Provides static information such as semimajor axis of ellipse,
  apogee and perigee altitudes, and anomalistic and nodal periods
  of satellite orbits.

* Command line options permit alternate groundstation locations to be
  specified or alternate orbital databases to be read and processed by
  the program, effectively allowing an UNLIMITED number of satellites
  to be tracked and managed.  Additional options allow any orbital
  database file to be automatically updated using NASA Two-Line element
  data obtained via the Internet or via pacsat satellite without having
  to enter the program and manually select menu options to update the
  database.

* A voice mode allows live azimuth and elevation headings of a satellite
  to be articulated to an observer to assist in locating a satellite by
  optical means.

* PREDICT can act as a socket-based server and be used to supply
  real-time tracking data, such as azimuth and elevation headings,
  footprint diameters, sub-satellite point latitude and longitude
  headings, normalized Doppler shift data, and next predicted AOS/LOS
  times to external programs such as rotator control software, graphical
  map tracking software, or radio frequency control programs residing
  either on the host machine, or on any networked client using the UDP
  communications protocol.

