Structural decomposition reference for the four-layer platform model
The four structural layers describe what the platform is. They are walked top-down (PCE to SEG to SVC to AST) so every smaller part names a parent and every analytic finding (Layer 5) attaches back to a real structural anchor. This reference covers Layers 1 through 4, the element enumeration process, and the annotation criteria every enumerated element must carry.
Walk the platform from the broadest layer down to the individual assets. Each step names the elements at that layer and links them to the layer above.
LAYER : TAG : LABEL : ORDINAL
All four fields are required, including the LABEL, written in full and exactly as published. Ordinals are scoped to the (LAYER, TAG) pair, so SEG : SP : Space : 00 and SEG : GR : Ground : 00 are not a collision: the tag codes differ.
Every enumerated element carries the same set of annotation fields. Required fields are mandatory; layer-specific fields apply only at the layer noted; optional fields are recommended where they add clarity.
| Field | Required? | Applies to | What to capture |
|---|---|---|---|
| LAYER | Required | All | One of PCE, SEG, SVC, AST. |
| TAG | Required | All | The published tag code within the layer (for example OR, SP, CP, HW). Use the tables below as the source of truth. |
| LABEL | Required | All | The published human-readable label, written in full (for example Orbital, Space, Control Plane, Hardware). Do not abbreviate or paraphrase. |
| ORDINAL | Required | All | Numeric instance counter starting at 00, scoped to the (LAYER, TAG) pair. New instances take the next ordinal; ordinals are never re-used. |
| DESCRIPTION | Required | All | One concise sentence describing this specific instance on your platform. Mission CONOPS language is fine; sales copy is not. |
| SOURCE / ARTIFACT | Required | All | The artifact this element was derived from: architecture diagram name and revision, system-design document section, asset inventory row id, CMDB record id. Without a source, the element is not traceable and must not be enumerated. |
| PARENT | Required | SEG, SVC, AST | The fully-qualified enumerated identifier of the parent element one layer above. Every SEG names its PCE, every SVC names its SEG, every AST names its SVC. No orphans. |
| DISTRIBUTED | Optional | SVC | Boolean, recorded as T (true) or F (false). Set to T when the service spans more than one segment (for example, a control plane that crosses ground and space via the link segment). |
| SUBSYSTEM | Optional | AST | Free-text grouping label that ties multiple assets together logically (for example bus, payload, ground-ops-room). Helps with rollups when the count of assets grows. |
Five environments. Where the platform operates. PCE elements have no parent; they are the top of the tree.
| Code | Label | Description | Parent |
|---|---|---|---|
| PCE-TE | Terrestrial | Land-based operating environment. | (top) |
| PCE-AQ | Aquatic | Surface or sub-surface water environment. | (top) |
| PCE-AE | Aerial | Atmospheric environment, low altitude through near space. | (top) |
| PCE-OR | Orbital | In-orbit environment within the gravitational regime of the parent body. | (top) |
| PCE-DS | Deep Space | Beyond the gravitational regime of the parent body. | (top) |
Ten segments. Operational role within an environment. Every SEG names its PCE parent.
| Code | Label | Description | Parent |
|---|---|---|---|
| SEG-LA | Launch | Launch operations, ending at vehicle separation. | PCE-TE |
| SEG-LI | Link | Communication path between segments. Signal asset is enumerated at L4. | PCE-TE / OR |
| SEG-GR | Ground | Ground stations, mission ops centres, control facilities. | PCE-TE |
| SEG-US | User | End-user equipment, terminals, identities. | PCE-TE |
| SEG-AQ | Aquatic | Maritime operations segment. | PCE-AQ |
| SEG-LO | Low Altitude | Low-altitude aerial operations. | PCE-AE |
| SEG-HI | High Altitude | High-altitude aerial operations. | PCE-AE |
| SEG-NE | Near Space | Near-space, between high altitude and orbital. | PCE-AE |
| SEG-SP | Space | On-orbit space segment, the operational constellation. | PCE-OR |
| SEG-DE | Deep Space | Deep-space mission segment. | PCE-DS |
Three services. Capability the segment delivers. Every SVC names its SEG parent. Mark a service DISTRIBUTED when it spans more than one segment.
| Code | Label | Description | Parent |
|---|---|---|---|
| SVC-CP | Control Plane | Command, control, configuration, and management of the platform. | SEG-* |
| SVC-DP | Data Plane | Mission product, payload data, and the data flows it produces. | SEG-* |
| SVC-HY | Hybrid | Service that spans both control and data plane responsibilities. | SEG-* |
Six asset classes. Concrete elements that implement a service. Every AST names its SVC parent and may carry an optional SUBSYSTEM grouping.
| Code | Label | Description | Parent |
|---|---|---|---|
| AST-HW | Hardware | Physical components, boards, buses, mechanical assemblies. | SVC-* |
| AST-FW | Firmware | Code burned to non-volatile memory; operates close to hardware. | SVC-* |
| AST-SW | Software | Operating systems, runtimes, applications, flight-software images. | SVC-* |
| AST-DA | Data | Mission data, telemetry, configuration, credentials. | SVC-* |
| AST-SI | Signal | RF or EM signal as an enumerated asset, distinct from the link segment that carries it. | SVC-* |
| AST-HY | Hybrid | Asset that spans more than one of the five primary asset classes. | SVC-* |
One coherent decomposition across the four structural layers. Every element carries an annotation set; only the identifier and parent are shown for table compactness.
| Identifier | Parent | Description (with source) |
|---|---|---|
| PCE : TE : Terrestrial : 00 | (top) | Terrestrial environment for ground operations and launch. Source: mission CONOPS doc-arch-001 sec. 2.1. |
| PCE : OR : Orbital : 00 | (top) | Low Earth Orbit environment for the operational constellation. Source: mission CONOPS doc-arch-001 sec. 2.2. |
| Identifier | Parent | Description (with source) |
|---|---|---|
| SEG : LA : Launch : 00 | PCE : TE : Terrestrial : 00 | Launch operations through vehicle separation. Source: launch ICD lic-101. |
| SEG : GR : Ground : 00 | PCE : TE : Terrestrial : 00 | Primary mission operations centre and tracking stations. Source: ground architecture doc-grd-002. |
| SEG : LI : Link : 00 | PCE : OR : Orbital : 00 | RF uplink/downlink between ground and constellation. Source: RF link budget doc-rf-003. |
| SEG : SP : Space : 00 | PCE : OR : Orbital : 00 | Operational LEO constellation, all on-orbit assets. Source: mission CONOPS doc-arch-001 sec. 3. |
| SEG : US : User : 00 | PCE : TE : Terrestrial : 00 | End-user mission terminals. Source: user terminal spec doc-usr-004. |
| Identifier | Parent | Description (with source) | Distributed? |
|---|---|---|---|
| SVC : CP : Control Plane : 00 | SEG : GR : Ground : 00 | Ground-side TT&C control plane. Source: ops procedure ops-cp-010. | F |
| SVC : CP : Control Plane : 01 | SEG : SP : Space : 00 | On-board command and configuration plane that ground commands traverse via the link. Source: flight-software spec doc-fsw-006. | T |
| SVC : DP : Data Plane : 00 | SEG : SP : Space : 00 | Mission payload data plane on each spacecraft. Source: payload ICD doc-pyld-007. | F |
| Identifier | Parent | Description (with source) | Subsystem |
|---|---|---|---|
| AST : HW : Hardware : 00 | SVC : CP : Control Plane : 00 | Mission ops console hardware. Source: CMDB asset id ast-hw-201. | ops-room |
| AST : SW : Software : 00 | SVC : CP : Control Plane : 00 | Ground command and telemetry software suite. Source: sw-bom v4.2. | ops-room |
| AST : SW : Software : 01 | SVC : CP : Control Plane : 01 | On-board flight-software image. Source: flight-software baseline fsw-3.7. | bus |
| AST : HW : Hardware : 01 | SVC : DP : Data Plane : 00 | Spacecraft bus hardware. Source: CMDB asset id ast-hw-301. | bus |
| AST : SI : Signal : 00 | SVC : CP : Control Plane : 01 | Uplink RF signal as an enumerated asset (the carrier of ground commands to space). Source: RF link budget doc-rf-003. | link |
| AST : DA : Data : 00 | SVC : DP : Data Plane : 00 | Primary mission data store on each spacecraft. Source: payload ICD doc-pyld-007. | payload |