Terms and Abbreviations
Table of contents
- Auxiliary Product
- Category
- Data Product
- Data Source
- Data Type
- Definition
- Equipment
- Essential Climate Variable (ECV)
- ECV Requirement
- Financial Transaction
- Instrument (Payload)
- Measurement Scale
- Measurement Unit
- Milestone
- Mission
- Mission Phase
- Name
- Organisation
- Parameter Type
- Parameter Value
- Parametric Constraint
- Platform
- Project
- Project Phase
- Requirement
- Requirement Group
- Requirement Specification
- Segment
- Short Name
- Space Programme
- SubSystem
- System
In the following we will refer to an element as any entity in EORSADB. For example, it can be a Mission, a Payload, a Programme, etc.
Auxiliary Product
An Auxiliary Product is a supporting or ancillary product associated with a Mission. It complements the primary Data Products.
Category
A Category is a means to classify elements with common characteristics. A category may belong to one or more Super Categories to form a hierarchy.
For example, a super category can be “Spectrometer” and one of its sub-categories could be “Cross-nadir shortwave (UV/VIS) sounder”.
Categories also define Permissible Classes that restrict which types of entities can be assigned that category.
Data Product
A Data Product represents geophysical measurements produced by instruments within a Mission. Data Products have a Data Product Level (e.g., L1, L2, L3) indicating the processing level.
Data Products can be linked to:
- The Mission that produces them
- Essential Climate Variables (ECVs) they help characterize
- Equipment (instruments) that measure them
- Auxiliary Products that support them
Data Source
The Data Source defines the origin of the data for a given element.
Data Type
This value defines the type of data. There are 3 possible values:
- Core data: Considered as official ESA data
- Non Core data: Data coming from other sources
- Fictional data: User-created or draft data for simulation purposes
Definition
The textual description of an element.
Equipment
An Equipment is an integrated set of parts and components (also called a Unit). Equipment can be hierarchically nested: an Equipment may contain child Equipments.
Equipment belongs to an Element (Payload or Platform) or to a parent Equipment.
Essential Climate Variable (ECV)
An Essential Climate Variable is a physical, chemical, or biological variable that contributes to the characterization of Earth’s climate. ECVs serve as a type of Requirements Group that organizes requirements specific to Earth Observation.
ECV Requirement
An Essential Climate Variable Requirement is a specific type of Requirement that is evaluated against Data Products to assess compliance with climate observation needs.
Financial Transaction
A Financial Transaction tracks budget and cost data associated with entities. Access to financial data may be restricted by role.
Instrument (Payload)
An Instrument (also referred to as a Payload) is a set of space segment elements that perform the user mission — i.e., the sensors, detectors, or measurement devices carried by a spacecraft.
Payloads can be hierarchically composed: a Payload may contain child Payloads. Payloads also define Spectral Bands they cover and contain Equipment and SubSystems.
Measurement Scale
A Measurement Scale defines how parameter values are quantified, providing the reference scale for numerical data.
Measurement Unit
A Measurement Unit defines the unit of measure (e.g., km, MHz, degrees) used by parameter values and measurement scales.
Milestone
A Milestone is a key event or review gate in a Mission Phase. Milestones track:
- Planned Date: The initially planned date
- Forecasted Date: The current forecast date
- Actual Date: The date the milestone was actually achieved
- Type: The kind of review (e.g., PDR, CDR, QR)
Mission
A Mission is a user-defined objective to be achieved by a space system. A Mission:
- Belongs to a Space Programme
- Contains Segments (Space, Launch, Ground)
- Has Mission Phases (e.g., LEOP, Operations, End-of-Life)
- Produces Data Products
- Has Requirements Specifications
- Has start and end dates
Mission Phase
A Mission Phase represents a stage in the lifecycle of a Mission (e.g., LEOP, Commissioning, Operations, End-of-Life). Each phase has start and end dates and may contain Milestones.
Name
The human-readable name of an element.
Organisation
An Organisation (or Agency) is a supplier or entity involved in space programmes. Organisations can be linked to Missions and may have a defined role in contracts.
Parameter Type
A Parameter Type defines what kind of values can be assigned to elements. The available types are:
| Type | Description |
|---|---|
| Boolean Parameter Type | True or false value |
| Date Parameter Type | A calendar date |
| Date Time Parameter Type | An exact date and time |
| Derived Quantity Kind | A value calculated from other values |
| Enumeration Parameter Type | A value picked from a predefined list (can be multi-select) |
| Simple Quantity Kind | A simple numerical value |
| Specialized Quantity Kind | A specialized numerical value |
| Text Parameter Type | A free-text value (e.g., the responsible Agency) |
| Time Of Day Parameter Type | A time within a day (no specific date) |
| Compound Parameter Type | A non-scalar type composed of multiple component parameter types |
| Array Parameter Type | A one-dimensional or multi-dimensional array of scalar elements |
Parameter Value
A Parameter Value is a concrete value assigned to an element, defined by its Parameter Type. Parameter Values are key data used when evaluating Parametric Constraints. See Parameter Values for the full how-to.
Parametric Constraint
A Parametric Constraint is a boolean expression belonging to a Requirement. It is evaluated against the Parameter Values on Missions and their sub-elements to verify compliance. The Boolean Expression Editor used to author them is described in Parametric Constraints, and an end-to-end example is given in the Worked Example.
Platform
A Platform is the part of a spacecraft that provides the support infrastructure — power, communications, navigation, and attitude control. A Platform belongs to a System and contains Equipment and SubSystems.
Project
A Project is a set of coordinated and controlled activities with defined start and finish dates. Projects:
- Are part of a Space Programme
- Link to Missions they are involved with
- Contain Project Phases
- May reference an Economic Condition
Project Phase
A Project Phase represents a stage within a Project lifecycle.
Requirement
A Requirement is a condition that needs to be verified. It can be an Environmental Observation requirement or a general requirement.
Requirements may have Parametric Constraints — boolean expressions that are evaluated against Mission parameter values.
Requirement Group
A Requirement Group organizes related Requirements. In the context of a Requirement Specification, it usually corresponds to a chapter or section. Requirement Groups can be nested.
Requirement Specification
A Requirement Specification belongs to a Mission and is the highest level of requirement grouping. It typically corresponds to a Mission Requirements Document (MRD) or a standard.
Segment
A Segment represents a major self-contained subset of a Mission. The Segment Type can be:
- Space Segment: The orbital elements (satellites)
- Launch Segment: The launch vehicles and associated elements
- Ground Segment: The ground stations and processing facilities
Each Segment contains Systems.
Short Name
The short name of an element for quick reference. For Requirements, it is usually the requirement number.
Space Programme
A Space Programme (also called a Programme) is a set of related space projects managed in a coordinated way. A Programme contains Missions and Projects.
SubSystem
A SubSystem is a component within an Element (Payload or Platform), representing a functional subdivision.
System
A System is a top-level assemblage within a Segment. Systems:
- Contain Elements (Payloads and Platforms)
- Link to Mission Phases they are active during
- Have Orbit Parameters defining their orbital characteristics
- May have a Two-Line Element (TLE) for satellite tracking
- Have start and end dates