For the complete documentation index, see llms.txt.VALAR supports industry-standard file formats for importing and exporting spacecraft orbital data, tracking observations, maneuver plans, and conjunction information. Most formats follow CCSDS (Consultative Committee for Space Data Systems) standards, ensuring interoperability with other space agencies, operators, and mission control systems worldwide.
Supported File Formats
VALAR supports eight primary file formats, each designed for specific operational needs:Format Categories
Orbital State Formats
These formats describe spacecraft position and velocity:- OPM: Single orbital state at a specific epoch, optionally with spacecraft properties
- OMM: Mean Keplerian elements at a single epoch, derived from osculating state via DSST
- OEM: Time series of orbital states with interpolation support for continuous trajectories
- OCM: Comprehensive format combining state history, maneuvers, physical properties, and force models
- SP3: Multi-satellite ephemeris with integrated clock corrections, primarily used for GNSS precise orbits
Observation Formats
These formats contain raw or processed measurement data from ground sensors:- TDM: Tracking observations (angles, range, range-rate) from ground stations or optical telescopes
Specialized Formats
- CDM: Conjunction analysis results with collision probability and miss distance
- TLE: Public catalog format using simplified perturbation models (SGP4/SDP4)
Quick Format Selection Guide
I want to…
Share a spacecraft state vector → Use OPM for a single-epoch snapshot Export mean orbital elements → Use OMM for TLE-equivalent mean element representation Provide a pre-computed trajectory → Use OEM for a time series of state vectors Import/export maneuver plans → Use OCM for comprehensive maneuver sequences Upload measurements for orbit determination → Use TDM for observation data from ground sensors Analyze conjunction events → Use CDM for collision assessment information Work with public catalog data → Use TLE format (note: VALAR does not import TLEs directly) Import precise GNSS or LEO satellite orbits → Use SP3 for IGS or similar precise orbit productsFormat Comparison
Temporal Scope
Data Complexity
Common Use Cases by Mission Phase
Format Details
OPM (Orbit Parameter Message)
Purpose: Exchange single-epoch orbital states with optional spacecraft parameters and a single maneuver. Key Features:- Cartesian state vectors or Keplerian elements
- Spacecraft physical properties (mass, area, coefficients)
- Optional covariance matrix
- CCSDS OPM: Standard format using inertial reference frames (EME2000, GCRF)
- SpaceX OPM: Proprietary format from Falcon second stage telemetry using ECEF coordinates
- Sharing orbit determination results
- Providing initial conditions for propagation
- Exchanging state vectors between systems
- Importing launch vehicle separation states (SpaceX OPM)
OMM (Orbit Mean-elements Message)
Purpose: Exchange mean Keplerian orbital elements at a single epoch, suitable for catalog distribution and TLE-equivalent data exchange. Key Features:- Mean Keplerian elements (averaged over short-period perturbations)
- Compatible with SGP4/SDP4 propagation parameters
- DSST-based osculating-to-mean element conversion
- Optional covariance matrix
- Exporting mean orbital state for catalog comparison
- Sharing TLE-equivalent data in structured CCSDS format
- Conjunction screening with stable mean elements
- Interoperability with mean-element-based workflows
OEM (Orbit Ephemeris Message)
Purpose: Share pre-computed spacecraft trajectories as time-ordered position and velocity data. Key Features:- Time series of Cartesian state vectors
- Interpolation methods (Hermite, Lagrange, Linear)
- Optional covariance matrices at each epoch
- Multiple data segments for different time periods
- Conjunction assessment coordination
- Trajectory sharing between control centers
- High-precision ephemeris distribution
- Orbit visualization and analysis
OCM (Orbit Comprehensive Message)
Purpose: Comprehensive mission planning format combining orbital states, maneuvers, spacecraft properties, and force model specifications. Key Features:- Multiple trajectory state blocks
- Multiple maneuver definitions (impulsive and continuous thrust)
- Maneuver sequencing (MAN_PREV_ID, MAN_NEXT_ID)
- Physical properties, covariance time history
- Perturbation parameters, user-defined data
- Import maneuvers from external sources
- Export maneuver plans for coordination with other agencies
VALAR uses OCM specifically for maneuver import/export. Other OCM sections (trajectory, physical properties, covariance) are not currently supported.
TDM (Tracking Data Message)
Purpose: Exchange ground-based tracking observations for orbit determination. Key Features:- Multiple measurement types (angles, range, range-rate (Doppler), frequency)
- Angle types: AZEL (radar), RADEC (optical), XEYN, XSYE
- Signal path specification (one-way, two-way)
- Multi-segment support for multiple tracking stations
- Metadata for corrections and biases
- Uploading measurements for orbit determination
- Sharing observation data from ground sensors
- Multi-station tracking campaigns
- Validating predicted trajectories against observations
CDM (Conjunction Data Message)
Purpose: Exchange conjunction assessment results for collision risk evaluation. Key Features:- Time of Closest Approach (TCA)
- Miss distance and relative velocity
- Collision probability
- State vectors and covariances for both objects
- Screening volume information
- Receiving conjunction warnings from Space-Track or other screening services
- Coordinating collision avoidance maneuvers
- Analyzing conjunction geometry
- Risk assessment for operational spacecraft
TLE (Two-Line Element)
Purpose: Compact format for distributing mean orbital elements from public satellite catalogs. Key Features:- Fixed 69-character line format
- Mean orbital elements (not osculating)
- BSTAR drag term for atmospheric decay
- Requires SGP4/SDP4 propagation models
- Distributed by Space-Track, CelesTrak
- TLE accuracy degrades rapidly (days to weeks depending on orbit)
- TEME reference frame (non-standard)
- Mean elements, not instantaneous orbital state
- VALAR does not support direct TLE import
- Use external SGP4/SDP4 library to propagate TLE
- Convert resulting state from TEME to GCRF or ITRF
- Import the state vector into VALAR as OPM format
SP3 (Standard Product 3)
Purpose: Distribute precise satellite orbits and clock corrections, primarily for GNSS constellations and LEO satellites. Key Features:- Multi-satellite support (up to 85 satellites per file)
- Integrated clock corrections at each epoch
- Multiple GNSS systems (GPS, GLONASS, Galileo, BeiDou, QZSS)
- LEO satellite support
- Optional velocity and correlation records
- Accuracy information via exponents and standard deviations
- Importing IGS precise orbit products
- Working with GNSS satellite ephemerides
- Precise Point Positioning (PPP) applications
- Orbit comparison and validation against IGS products
SP3 is an IGS (International GNSS Service) standard, not a CCSDS format. It is widely used in the geodetic and GNSS communities.
File Format Standards
CCSDS Standards
Most formats follow CCSDS (Consultative Committee for Space Data Systems) recommendations:- CCSDS 502.0-B-3: Orbit Data Messages (OPM, OEM, OCM, OMM)
- CCSDS 503.0-B-2: Tracking Data Message (TDM)
- CCSDS 508.0-B-1: Conjunction Data Message (CDM)
Other Standards
- IGS SP3-c: Standard Product 3 format for precise GNSS orbits and clocks
- Space agencies (NASA, ESA, JAXA, etc.)
- Commercial satellite operators
- Ground station networks
- Mission control centers
- Orbit determination systems
KVN vs XML Format
CCSDS formats support two representations: KVN (Keyword-Value Notation)- Human-readable ASCII text format
- Easier to parse and debug
- Smaller file sizes
- Preferred for operational use
- VALAR uses KVN format
- Structured hierarchical format
- Machine-readable with schema validation
- Better for complex nested data
- Common in enterprise systems
Reference Frames and Time Systems
All CCSDS formats specify reference frames and time systems explicitly:Common Reference Frames
Common Time Systems
See Reference Frames documentation for detailed information about coordinate systems and transformations.
Best Practices
File Import/Export
- Validate before sharing: Ensure files conform to CCSDS standards
- Include comments: Document assumptions, corrections, and data sources
- Specify units explicitly: Don’t rely on default unit assumptions
- Use appropriate precision: Match numerical precision to accuracy requirements
- Test round-trip: Verify data integrity through import/export cycles
Format Selection
- Match format to purpose: Don’t use OCM when OPM suffices
- Consider file size: OEM files can be large for long time spans
- Document extensions: If using non-standard fields, provide ICD documentation
- Standardize internally: Use consistent formats within your organization
- Maintain compatibility: Verify receiving systems support your format choices
Reference Frame Selection
- Use GCRF for propagation: Modern inertial frame, well-defined
- Use ITRF for ground operations: Earth-fixed frame for station coordinates
- Document LOF definitions: LVLH, RTN naming varies between organizations
- Convert early: Transform non-standard frames (TEME) to standard frames quickly
Time System Selection
- Prefer UTC for operations: Most universally understood
- Use TAI for precision work: Avoids leap second discontinuities
- Document time system clearly: Ambiguity causes significant errors
- Maintain consistency: Don’t mix time systems within a file
Getting Help
For detailed information about each format:- Browse individual format documentation pages
- Consult CCSDS specifications (linked in each format page)
- Review example files provided in documentation
- Contact VALAR support for import/export questions