TCTE TIM Data Products Release Notes

TCTE TIM Version 4 (06 March 2020):

Final release supported by the TCTE mission. TSI data is available between 2013-12-16 and 2019-05-16 (same as V.3).

  • Calibration adjustment: updated dark model, servo gain, and degradation model.
  • Minor algorithm updates.

TCTE TIM Version 3 (10 April 2019):

TCTE completed its science mission and was permanently turned off on July 1, 2019. TSI data is available between 2013-12-16 and 2019-05-16.

  • Utilizes TLEs (two-line elements) to determine spacecraft position and velocity for distance and Doppler corrections. That change from using the GPS in prior versions is implemented across the entire mission timeframe and fills in times when the spacecraft’s GPS was not functioning.
  • Calibration adjustments: updated dark model, thermistor (Steinhart-Hart parameters), and servo gain.
  • Numerous internal processing improvements from work on SORCE-TIM and TSIS-TIM

TCTE TIM Version 2 (12 March 2015):

At the beginning of 2015, TCTE resumed daily observations and version 2 incorporates them. Improved calibration and correction models were implemented in several areas:

  • Cone temperature is now modeled as a fixed offset higher than observed core temperature rather than a constant value
  • The servo-gain phase is now modeled as a function of temperature
  • Heater node resistance and cavity reflectance calibration values were updated
  • The dark irradiance correction now incorporates a temperature-sensitive model based on irradiances observed in flight

TCTE TIM Version 1 (16 July 2014):

  • V.1 is the first public release of TCTE TIM data. The V.1 estimated absolute accuracies are 0.1% and will be improved in future versions as additional corrections are applied. All ground-based calibrations are included. Dark corrections are currently approximated and will be refined to include temperature dependencies. Degradation corrections due to solar exposure are not yet applied, but are expected to be small since the TIM has proven very stable on the SORCE mission. The on-orbit measurements for future dark and degradation corrections are being acquired and will be applied in V.2 (updated 13 Jan. 2015).