Jonathan's Space Pages

Catalog of Space Debris Clouds - Column Descriptions

Note that in the description below, "height" means the orbit semi-major-axis minus the Earth equatorial radius; equivalently, it is the average of the perigee and apogee values: (p+a)/2.

The columns in the catalog are:

• Catalog number - a simple running number for this catalog. Has a link to the data page for this cloud.
• Piece - the international designation for the launch that this cloud is associated with. Has a link to the data page for this cloud.
• Data - the primary debris cloud data plot; see the Plots documentation.
• Height history - a plot showing height vs time for each debris object in the cloud. This gives a general sense of the extent to which the cloud is affected by orbital decay. See the Plots documentation.
• Gabbard - the Gabbard diagram for the latest orbits for the debris.
• AngMom - a plot characterizing the specific angular momentum vectors of the debris objects.
• Name - name of the parent object
• Parent - General Catalog ID (JCAT number) of the parent object
• SDate - Date of the debris event. (For extended duration releases - type Insul - this is the date when debris shedding first began).
• DDate - Date when the last object reentered, for clouds which have now completely reentered.
• Long, Lat - Estimated geographic longitude and latitude (deg) of parent object at the time of the debris event. These values are usually highly uncertain; don't take them too seriously. The values in the ODPO History of On Orbit Fragmentations are different and are likely to be more reliable.
• Height - Altitude in km of the parent object at the estimated time of the debris event.
• EventType - Classification of the origin of the debris cloud. Values are:

  Event type	meaning
  Aerodyn	Aerodyamic breakup due to low perigee approaching reentry
  ASAT	Destruction by antisatellite weapon
  Coll	Collision with another orbiting object
  Coolant	Frozen coolant blobs leaked from orbital nuclear reactor
  Batt	Battery explosion
  Burn	Broke up during rocket firing
  Destruct	Deliberate self-destruction with onboard explosive
  Disint	Structural disintegration (e.g. balloon breakup)
  Deploy	objects are not debris, but deliberately deployed (notably, see the West Ford dipoles)
  Insul	Possible insulation shedding - debris generation continues over a period of time
  Resid	Propellant-related breakup, usually ignition of residual propellant
  Sep/Coll	Collision with parent object during separation
  Slag	suspected solid rocket motor slag released during rocket firing
  Tumble	Structural disintegration due to tumbling or spin
  Release	deliberate non-destructive release of sub-objects
  Unk	Unknown

• EventPeri - perigee (km) of parent object orbit at time of event
• EventApo - apogee (km) of parent object orbit at time of event
• EventInc - inclination (deg) of parent object orbit at time of event
• NCat - Number of cataloged objects associated with this cloud. (May include analyst objects in some cases).
• HtLo, HtHi - 95 percent of the current orbits of the debris cloud objects have heights between these values (in km). For clouds which have entirely reentered, the final known orbits are used.
• IncLo, IncHi - 95 percent of the current orbits of the debris cloud objects have heights between these values (in km). For clouds which have entirely reentered, the final known orbits are used.
• ApseMode

  
  In a debris cloud whose parent was in a circular orbit at height h, the initial orbits of the debris objects usually have either their apogee or their perigee equal to h. I make a histogram of these apogee and perigee values (lumped together) and find the mode of that histogram (in km). This ApseMode value is often a good estimate of the height at which the debris event occurred.

• Filename - the root name of the files with data and plots for this cloud.
• Label - a short label that can be used to identify the cloud on plots showing multiple clouds.