Conjunction Events

A conjunction event represents a time where two objects fall within our screening volume at their time of closest approach (TCA).

When the conjunction screening system generates a CDM whose time of closest approach is within 20 minutes of an existing conjunction event, that CDM is associated with that conjunction event. Otherwise, a new conjunction event is created.

Note that close approaches with very low relative velocities (rare in Low-earth orbit) may see their TCA change by > 20 minutes. In this case, multiple conjunction events may be created for the same close approach.

More CDMs may be associated with a conjunction event as operators continue to submit trajectories associated with the objects.

Conjunction events may contain multiple "active" CDMs, which contain different estimates for the conjunction geometry and conjunction risk based on different state sources for the trajectories (i.e., operator_ephemeris trajectories submitted by operators vs. spacex_optical trajectories produced by Stargaze). Read more about this in the CDMs docs.

Hypothetical Trajectories

Hypothetical trajectory submissions do not generate conjunction events, only CDMs. This prevents confusion by preventing conjunction events from grouping "real" CDMs (generated by definitive trajectories) with CDMs that were only generated for planning/analysis purposes.