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Recommendations

Satcat Recommendations assist operators in making informed decisions based on the data in a given CDM. These recommendations can help quickly interpret complex conjunction metrics and identify whether risk mitigation or tracking actions are warranted.

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Satcat 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.

Overview​

Satcat Recommendations are generated for every individual CDM ingested into the system. Different CDMs for the same conjunction event may have different recommendations based on the data available in that particular CDM. CDMs differ in the data sources used for the primary and secondary tracking data, the originator of the CDM, and the time the CDM was generated. Be sure to consider which CDM to review when evaluating 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 we can be confident enough in the data in the CDM to make operational decisions based on it. 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.

In general, Satcat only recommends mitigation planning when a CDM demonstrates high risk and is actionable. CDMs are considered "not actionable" if the data does not provide sufficient confidence to make operational decisions, even if the risk is high. The most common example of this is high lead time. Because uncertainty grows with the prediction span, CDMs with high lead time tend to have high uncertainty and high Pc values.

Why not recommend mitigation for all high-risk events?

Collision avoidance maneuvers are often high-energy events that involve off-nominal mission operations, thruster firings that can fail or underperform, incur some fuel cost, and always inject some additional uncertainty into the mission. CDMs which are considered "not actionable" often represent a poor understanding of the orbital situation, and in the worst cases, performing COLA maneuvers based on these CDMs can even be counterproductive.

Satcat's Recommendation system helps you interpret both risk and actionability metrics together to minimize the impact of COLA planning on mission operations.

Recommendation Types​

Satcat makes two types of recommendations:

  • Mitigation Recommendations indicate whether operators should consider planning mitigation actions such as collision avoidance maneuvers to reduce the risk of collision.
  • Tracking Recommendations indicate whether operators should consider requesting additional tracking data to improve orbit knowledge and reduce uncertainty before TCA. Operators can make use of Satcat's On-Demand Sensor Tasking system to request additional tracking data for conjunction events.

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 Satcat's Ephemeris Repository, 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:

  • Request tasking (High priority): Request high-priority tracking when additional observations may support time-sensitive mitigation planning.
  • Request tasking (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.
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Sensor tasking availability depends on your Operations service tier and sensor allocation.
Learn more about Sensor Tasking

How Satcat Evaluates Recommendations​

Each Satcat recommendation comes with a Reasoning summary detailing the factors which were considered in synthesizing the recommendation.

Satcat's recommendation system evaluates the following metrics to determine whether mitigation or tracking actions are warranted:

  1. Risk thresholds: Satcat evaluates the Probability of Collision (Pc) value against your group's configurd Mitigation Action Thresholds. Note that not all CDMs with Pc exceeding threshold are recommended for mitigation, because they may not have an actionable risk estimate. Conversely, not all CDMs with Pc below threshold are considered safe because they may be diluted.
  2. Pc dilution: Satcat evaluates whether the Probability of Collision (Pc) value is diluted due to large covariance relative to the conjunction geometry, which can lead to underestimation of collision risk. CDMs whose nominal Pc both exceeds the threshold and is diluted are considered particularly dangerous, because the true risk may be even higher than the nominal Pc value indicates. Learn more about Pc dilution.
  3. Lead time: Satcat evaluates the lead time of the CDM compared to the Mitigation Action Time Before TCA threshold configured for your group. In general, mitigation actions are not recommended for CDMs with high lead time, but tracking actions may be recommended to improve understanding of the orbital situation before TCA.
  4. Max Pc: In cases where the nominal Pc is diluted and below the Mitigation Action Pc Threshold, Satcat checks whether the Max Pc given the primary's covariance exceeds the threshold. In these cases, Satcat recommends requesting additional tracking data to produce a more actionable orbit estimate of the secondary object.
  5. OD quality: Satcat evaluates the orbit determination (OD) quality of the secondary state estimates in the CDM. If the OD quality is poor, Satcat may recommend requesting additional tracking data to produce a more actionable orbit estimate of the secondary object.

Limitations​

Recommendations depend on the quality and completeness of the selected CDM and event metadata. A recommendation may be unavailable or conservative when Satcat cannot evaluate required context such as Pc, covariance, maneuverability, threshold settings, or time-to-TCA.

Satcat Recommendations make it easy to interpret Risk and Actionability metrics together, but they don't take your mission-specific constraints or operational considerations into account. Operators remain responsible for mitigation, coordination, and tracking decisions.