Data Access
The L1 STATE files contain the following data, sampled at one-minute intervals:
* probe position and velocity in GEI, GSE, and GSM coordinates;
* flags to indicate regions of interest and maneuver status;
* RA and declination of spin axis;
* spin period and spin phase;
* spin model parameters for high-precision interpolation of spin phase between one-minute data points.
Version number indicates data source as follows:
* V00: predicted ephemeris and attitude, no spin period or spin phase;
* V01: predicted ephemeris and attitude, spin period and spin phase derived from probe telemetry;
* V02: predicted attitude, definitive ephemeris from magnetometer and Doppler tracking data;
* V03: corrected attitude and spin phase derived from fully calibrated magnetometer data (added science attitude determination using perigee data post-processing).
Produced by Mission Ops, Science Ops and Science Team.Version:2.3.1
The L1 STATE files contain the following data, sampled at one-minute intervals:
* probe position and velocity in GEI, GSE, and GSM coordinates;
* flags to indicate regions of interest and maneuver status;
* RA and declination of spin axis;
* spin period and spin phase;
* spin model parameters for high-precision interpolation of spin phase between one-minute data points.
Version number indicates data source as follows:
* V00: predicted ephemeris and attitude, no spin period or spin phase;
* V01: predicted ephemeris and attitude, spin period and spin phase derived from probe telemetry;
* V02: predicted attitude, definitive ephemeris from magnetometer and Doppler tracking data;
* V03: corrected attitude and spin phase derived from fully calibrated magnetometer data (added science attitude determination using perigee data post-processing).
Produced by Mission Ops, Science Ops and Science Team.| Role | Person | |
|---|---|---|
| 1. | PrincipalInvestigator | spase://SMWG/Person/Vassilis.Angelopoulos |
Overview of THEMIS data, descriptions, and data policy.
Details on THEMIS data policy and giving proper credits in publications.
Ephemeris file format and quantity details including RoI descriptions.
NASA/GSFC CDAWeb ftp access to the data.
In CDF via HTTP from SPDF
Access to ASCII, CDF, and plots via NASA/GSFC CDAWeb
CDF data files for download, organized by date.
THEMIS-A position vector (km) in GEI coordinates.
THEMIS-A velocity vector (km/s) in GEI coordinates.
THEMIS-A maneuver status code (XYYZZZ). Values indicate if/what maneuver is being performed. Spacecraft data will be unreliable during maneuvers.
* Unpowered flight (Coast):
- X=0, Y=00, Z=000
* Sequence Code X:
- 0= No Segmentation
- 1= Segmented Maneuver
* Type Code YY:
- 0= No Maneuver
- 1= Axial-thrust Maneuver
- 2= Side-thrust Maneuver
- 3= Beta-thrust Maneuver
- 4= Attitude Precession
- 5= Spin-Rate Change
* Sequence Number ZZZ:
- 001-999= Maneuver Sequence NumberRegion of interest. Different bits of this parameter give a general indication of the region that the spacecraft is in. The first 18 bits are significant. An active bit indicates the spacecraft is in a given region. Multiple bits may be set simultaneously. The value of the bit is in parentheses in the following table.
+---------------------------------------------------+
| Bit 1(1) | Earth Shadow |
| Bit 2(2) | Lunar Shadow |
| Bit 3(4) | Atmospheric absorbtion zone |
| Bit 4(8) | South Atlantic Anomaly |
| Bit 5(16) | Northern Auroral Zone |
| Bit 6(32) | Southern Auroral Zone |
| Bit 7(64) | Perigee Passage |
| Bit 8(128) | Inner & Outer Radiation Belts |
| Bit 9(256) | Deep Plasma Sphere |
| Bit 10(512) | Foreshock Solar Wind |
| Bit 11(1024) | Solar Wind Beam |
| Bit 12(2048) | High Magnetic Field |
| Bit 13(4096) | Average Plasma Sheet |
| Bit 14(8192) | Bowshock Crossing |
| Bit 15(16384) | Magnetopause Crossing |
| Bit 16(32768) | Ground Based Observatories |
| Bit 17(65536) | 2-Day Conjunctions |
| Bit 18(131072)| 4-Day Conjunctions |
+---------------------------------------------------+THEMIS-A spin axis right ascension in GEI coordinates.
THEMIS-A spin axis declination in GEI coordinates.
THEMIS-A spin axis azimuth, Euler alpha, in Probe Geometric (SPG) coordinates
THEMIS-A spin axis colatitude, Euler beta, in Probe Geometric (SPG) coordinates
THEMIS-A spin period, regularized and boxcar averaged.
THEMIS-A angle rotated since the sun sensor registered the sun pulse, regularized and boxcar averaged.
Time, UTC, in seconds since 01-Jan-1970 00:00:00.
Spin correction time, UTC, in seconds since 01-Jan-1970 00:00:00
Initial spin period for segment.
Spin time, UTC, in seconds since 01-Jan-1970 00:00:00.
Segment end time, UTC, in seconds since 01-Jan-1970 00:00:00
Drift term for spin rate
Spin phase correction from definitive position and field model calculated at 1 minute intervals
Spin axis right ascension correction from definitive position and field model
Spin axis declination correction from definitive position and field model
Maximum absolute phase error between model and non-outlier sun crossing time.
Number of spins contained in this segment.
Number of samples (points) contained in this segment.
Duration, in seconds, of longest gap between sun pulses in this segment. Long gaps (60 sec or more) will generally indicate shadow periods.
Spacecraft position vector (km) in GSE coordinates.
Spacecraft position vector (km) in GSM coordinates.
Spacecraft velocity (km/s) in GSE coordinates.
Spacecraft velocity (km/s) in GSM coordinates.