Conjunction Classification

The Conjunction Classification page lets you monitor close approach events between your spacecraft and other space objects. View conjunction data, assess collision risk levels, and manage alerts from different originators. Route: /conjunctions/current or /conjunctions/historical

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Page Layout

The page displays a details panel on the left and a scrollable conjunction list on the right. Two tabs at the top switch between views:

• Current — Active conjunctions with upcoming TCA (Time of Closest Approach)
• Historical — Past conjunction events for review

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Filtering and Sorting

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Spacecraft Filter

Use the spacecraft dropdown in the toolbar to show conjunctions for specific spacecraft only. Select one or more spacecraft, then click Apply. When no spacecraft are selected, all conjunctions are shown.

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Grouping

Group conjunctions by:

• Spacecraft — Groups by your primary spacecraft
• Criticality — Groups by risk level (High, Medium, Low)
• None — Flat list with no grouping

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Sorting

Sort in Ascending (earliest TCA first) or Descending (latest TCA first) order.

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Conjunction List

Each row in the list displays:

• Code — Conjunction identifier
• Risk Shield — Color-coded icon indicating criticality (red, yellow, or green)
• TCA — Date and time of closest approach (hover for full UTC timestamp)
• Miss Distance — Color-coded icon (hover for value in meters)
• PoC — Color-coded icon (hover for Probability of Collision value)
• Spacecraft — Colored satellite icon matching your spacecraft (hover for name)
• Last Updated — Relative time since the conjunction was last updated (hover for full timestamp)

Click any row to view its details in the left panel.

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Risk Levels

Conjunctions are classified into three risk levels based on your configured thresholds (see Settings):

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Details Panel

Selecting a conjunction opens its details on the left. The panel includes:

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Summary

Key parameters at a glance:

• Criticality — Risk level (High, Medium, Low) with color-coded shield
• Miss Distance — Predicted closest approach in meters, with radial, along-track, and cross-track breakdown on hover
• PoC — Probability of Collision in scientific notation
• TCA — Time of Closest Approach with countdown timer

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Trend Analysis

When multiple alerts exist for a conjunction, a chart shows how miss distance or PoC has evolved over time. Each data point is color-coded by its originator (e.g., CSpOC, ESA, Valar).

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Encounter Plane (B-Plane)

For conjunctions with B-plane data, an interactive visualization shows the relative geometry at closest approach:

• Primary object at the center with its covariance ellipse
• Secondary object position relative to the primary
• Uncertainty boundaries at 1σ, 2σ, and 3σ levels

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State Vectors

Expandable sections display orbital state data for both objects, including position and velocity in Cartesian coordinates, position uncertainty in the RTN frame, and the reference frame used.

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Import Alerts

Import alerts from CDM files:

1. Click Import in the toolbar
2. Select the target spacecraft
3. Drag and drop files or click to browse
4. Supported formats: .cdm, .xml, .txt

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Export Alerts

Export a conjunction’s alerts as CDM files:

1. Select a conjunction from the list
2. Click the More menu (⋮) in the details panel header
3. Select Export Alerts

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Delete Conjunction

1. Select the conjunction
2. Click the More menu (⋮) in the details panel header
3. Select Delete and confirm

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Settings

Configure how conjunctions are classified via Settings → STM → Conjunctions.

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PoC Thresholds

Set the Probability of Collision values that define each risk level: Conjunctions below the Medium threshold are classified as Low risk.

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Miss Distance Thresholds

Set the miss distance values that define each risk level. Lower distances indicate higher risk: Conjunctions above the Medium threshold are classified as Low risk.

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PoC Computation Method

Select the algorithm used to calculate Probability of Collision:

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Editing Thresholds

1. Click the Edit icon next to a threshold section
2. Enter new values (scientific notation for PoC, meters for miss distance)
3. Click Save to apply

This page also lets you configure credentials for external data providers (SpaceTrack, EU SST). See Fetch Alerts — Provider Credentials for details.

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Related Pages

• Conjunction Computation — Compute conjunctions using your own state vectors
• Fetch Alerts — Download alerts from external space surveillance providers
• CDM Format — Conjunction Data Message file format reference