Constellations and RSOs
RSOs can be grouped into constellations, and each is listed with its identifiers, mean orbit, and how current its operational ephemeris is. Ephemeris is uploaded here, and objects that are not yet cataloged are held under temporary identifiers.
Organizing RSOs
Constellations group an organization's RSOs. Selecting a constellation narrows the list to its members; All RSOs covers every RSO in the organization. Both carry a count.
An RSO can belong to more than one constellation. Constellations are organizational groupings only: they do not influence tasking, screening, or alert behavior, and deleting one leaves its RSOs untouched.
The same constellation grouping applies to orbit determination solutions and uploaded ephemeris.
Ephemeris
An ephemeris defines an RSO's predicted trajectory, typically based on a recent orbit determination. Satcat uses ephemeris to compute conjunction risk and generate CDM reports.
Each file carries a Designation and a Context, which together determine how Satcat and other operators may use it. Both are defined in Ephemeris Metadata.
Only OPERATIONAL ephemeris and data derived from it can be used by other operators. Uploading OPERATIONAL ephemeris also generates new CDMs for affected conjunction events, and advances the ephemeris age and forward coverage shown against the RSO.
Learn about Operational Ephemeris
Uploading Ephemeris
Ephemeris can be uploaded here, from within a conjunction event, or through the SDK and API. Each uploaded file is listed with its upload date, associated NORAD ID, usable start and end times, and its designation and context.
An upload needs three things:
- The file and its format. Auto-detect is recommended. View supported file formats
- A NORAD ID. Only RSOs belonging to the organization are eligible.
- A designation and context.
Automating Uploads
Automated uploads keep conjunction assessment on current operator data.
- Upload through the Satcat SDK or REST API
- Authenticate with an API key
RSOs
| Column | Description |
|---|---|
| Identifiers | Common name, NORAD ID, and international designator |
| Mean orbit | Apogee by perigee altitude and inclination, or Decayed |
| Ephemeris age | How long ago the latest operational ephemeris began |
| Forward coverage | How far that ephemeris extends beyond the present |
The list can be searched and filtered by on-orbit status, object type, and ephemeris age.
Parameter values are edited through an RSO's Edit option, covered in RSO Parameters.
Ephemeris Age and Forward Coverage
These two columns describe whether an RSO's operational ephemeris still covers where it is now and where it is going.
| Ephemeris age | Meaning |
|---|---|
| Fresh | Began within the last 24 hours |
| Aging | Began 24 to 48 hours ago |
| Stale | Began more than 48 hours ago |
| Missing | No operational ephemeris at all |
| Forward coverage | Meaning |
|---|---|
| Current | Extends more than 48 hours ahead |
| Expiring | Extends less than 48 hours ahead |
| Expired | Ends before the present, shown as a time in the past |
An RSO reading stale or expired has no operational ephemeris covering the present. Conjunction assessment falls back to catalog data for that object, which is less accurate than operator data, and does not contain planned maneuvers.
Uncorrelated Objects
During launch and early orbit phase (LEOP), objects that have not yet been formally cataloged may be tracked under temporary identifiers in the 799xxxxxx (9-digit) range. These identifiers are used with sensor-acquired or operator-supplied state data that has not been correlated to a cataloged object.
- Temporary IDs must follow the
799prefix convention. - These objects are included in orbit determination and conjunction assessment.
- Once a NORAD ID is assigned, the temporary identifier is unlinked.
Uncorrelated objects appear alongside an organization's other RSOs and support the same parameters.
An uncorrelated object holds the same operational data as a cataloged RSO, so operational ephemeris uploaded against a temporary identifier is used in screening the same way.