Recommendations
A recommendation is the action Satcat suggests for a single CDM, weighing the risk that CDM reports against how much confidence its data supports. One is generated for every CDM, so CDMs on the same conjunction event can carry different recommendations depending on the tracking data behind them, the originator, and when they were generated.
Recommendations are designed to facilitate informed operational decision making, but should always be used alongside a detailed analysis of the conjunction data to make a final decision.
Recommendation Types
Satcat makes two kinds of recommendation for each CDM: mitigation and tracking.
Mitigation Recommendations
Mitigation recommendations summarize the primary operational posture for the selected CDM:
- No Action: No mitigation action is recommended given the data in the current CDM.
- Wait for Update: Monitor for an updated CDM before committing to mitigation.
- Plan Mitigation: Consider planning a mitigation action to reduce conjunction risk.
- Coordinate: Coordinate with the other operator before taking mitigation action, typically because the secondary is maneuverable. Coordination can be done in Satcat by uploading Operational ephemeris to Catalog Data, through Satcat's Contact Center, or by using Satcat's Mitigation Intent system.
- Unable to Act: Mitigation planning would otherwise be recommended, but the primary object is not maneuverable.
- No Recommendation: Satcat could not make a recommendation for the selected CDM.
Tracking Recommendations
Tracking recommendations identify whether additional observations should be requested to improve orbit knowledge before TCA. Tasking is requested from Satcat's On-Demand Sensor Tracking system.
- Request Tracking (High Priority): Request high-priority tracking when additional observations may support time-sensitive mitigation planning.
- Request Tracking (Low Priority): Request lower-priority follow-up tracking when observations may improve future CDM updates without indicating urgent tasking.
- No Tracking Action: No separate tracking recommendation is available for the selected CDM.
Sensor tasking availability depends on the organization's Operations service tier and sensor allocation.
How Satcat Evaluates Recommendations
Satcat's recommendation system is based on NASA CARA's Spacecraft Conjunction Assessment and Collision Avoidance Best Practices Handbook. At the highest level, Satcat considers two factors when making recommendations:
- Risk indicates the likelihood that the event will occur based on the data in the CDM. The primary risk metrics used in recommendations are the Probability of Collision (Pc) and the maximum probability of collision (max Pc).
- Actionability indicates whether the data in the CDM supports an operational decision. The primary actionability metrics used in recommendations are the lead time (time from CDM creation to TCA), Pc dilution, and the orbit determination (OD) quality of the state estimates in the CDM.
Satcat recommends mitigation planning only when a CDM is both high risk and actionable. A CDM is not actionable when its data does not support an operational decision, most often because of high lead time: uncertainty grows with the prediction span, so distant CDMs tend to carry both high uncertainty and high Pc. Maneuvering on one can be counterproductive, and a collision avoidance maneuver is never free: it costs fuel, depends on a thruster firing that can fail or underperform, and injects additional uncertainty into the mission.
Each recommendation carries a Reasoning summary of the factors behind it.
Satcat's recommendation system evaluates the following metrics to determine whether mitigation or tracking actions are warranted:
- Risk thresholds: Pc is measured against the organization's Mitigation planning threshold, either one of its configured risk levels or a custom set of values. Crossing it does not by itself produce a mitigation recommendation, and staying below it does not by itself mean safe. Miss distance is only considered when the Pc is robust and below threshold, and is measured against the organization's Mitigation miss distance threshold. If only the miss distance threshold is crossed, Satcat recommends waiting to monitor future CDMs.
- Pc dilution: a diluted Pc can understate risk, so a CDM both above the threshold and diluted may carry higher true risk than its Pc indicates. See Pc dilution.
- Lead time: measured against the Lead time before TCA value on that threshold, in hours. High lead time suppresses a mitigation recommendation and favors a tracking one.
- Max Pc: where the nominal Pc is diluted and below the threshold's Pc value, Satcat tests the max Pc from the primary's covariance. Crossing it produces a tracking recommendation.
- OD quality: poor OD quality on the secondary state favors a tracking recommendation. See OD Quality Ratings.
The threshold is configured in Control Center under Organization Settings, and applies to the whole organization.
Acting on a Recommendation
A recommendation records what Satcat suggests; it does not change the conjunction event. Each one is acted on from the surface that owns the action.
| Recommendation | Action |
|---|---|
| Plan Mitigation | Design a maneuver in Maneuver Designer, then weigh the resulting plans on CDM comparison |
| Coordinate | Reach the other operator through the coordination surfaces before maneuvering |
| Request Tracking | Request tasking for the conjunction event, covered on Sensor Tasking |
| Wait for Update | Nothing until the next CDM arrives |
| No Action, Unable to Act, No Recommendation | Nothing to act on for this CDM |
A mitigation takes effect only once its ephemeris is uploaded with an OPERATIONAL designation. Until then the conjunction event still reflects the data already in place. See Enacting a Mitigation Plan.
Limitations
A recommendation reflects the selected CDM only, and depends on that CDM carrying the inputs above. Where one is missing, Satcat returns No Recommendation rather than inferring one.
Recommendations do not account for mission-specific constraints or operational considerations. Operators remain responsible for mitigation, coordination, and tracking decisions.