NOAA Office of Satellite and Product Operations

NOAA 12 ADACS Subsystem Summary

Component Status:

ESAEarth Sensor AssemblyGreen
GYRO 1Gyroscopic Rate Measuring Device #1 -Yaw (X)Green
GYRO 3Gyroscopic Rate Measuring Device #3 -Pitch (Z)Green
GYRO 4Gyroscopic Rate Measuring Device #4 -Skew (S)Yellow
IMUInertial Measurement UnitGreen
PTC 1APitch Torque Coil 1AGreen
PTC 1BPitch Torque Coil 1BGreen
PTC 2APitch Torque Coil 2AGreen
PTC 2BPitch Torque Coil 2BGreen
RWA SSkew Reaction Wheel AssemblyGreen
RWA XX-axis Reaction Wheel AssemblyGreen
RWA YY-axis Reaction Wheel AssemblyGreen
RWA ZZ-axis Reaction Wheel AssemblyGreen
RYTC 1ARoll-Yaw Torque Coil 1AGreen
RYTC 1BRoll-Yaw Torque Coil 1bGreen
RYTC 2ARoll-Yaw Torque Coil 2AGreen
RYTC 2BRoll-Yaw Torque Coil 2BGreen
SSASun Sensor AssemblyGreen

Subsystem History:

Date Time Component Description
08/06/200718:49:00 Automatic thruster unloading enabled.
08/31/200620:22:00 Return to nominal attitude control mode (from YGC).
08/31/200620:21:00IMUDisable ground IMU override.
08/31/200620:20:00GYRO 4When commanding spacecraft back to nominal mode, skew gyro was swapped OUT and X-Yaw gyro swapped back in.
08/31/200620:20:00IMUSet IMU override.
08/30/200602:46:00GYRO 4Autonomous switch to YGC mode also resulted in X-gyro (Yaw) being autonomously swapped out for the skew gyro.
08/30/200602:45:00SSASun sensor became shaded by the solar array during a yaw update which caused an excessive update value that caused an autonomous switch to YGC attitude control mode.
06/01/200612:00:00RWA XX-reaction wheel (yaw) recently began crossing below 0 RPM into negative speeds. When the speed/direction crosses through 0 RPM, the wheel sometimes sticks which can potentially impact yaw updates.
04/06/200408:15:00 N12 flight GEODAT providing incorrect eclipse predictions inconsistent with ground GEODAT predictions.
04/02/200414:05:00 Command spacecraft attitude control mode back to NOMINAL from YGC.
04/01/200420:50:00 Excessive yaw update following software patch to re-enable yaw updates. Recovered after 4 orbits.
04/01/200420:45:00 After patching flight software to re-enable Yaw updates a yaw update immediately occured with a bad value causing a 2 degree yaw error.
10/02/200317:05:00GYRO 1Commanded yaw control back to orthogonal gyro-1(X) from skew gyro-4 (S). Restored yaw bais to previously known good value.
09/12/200308:35:21GYRO 1Gyro-1 (orthogonal/yaw) autonomously DEselected because of switch to YGC mode
09/12/200308:35:20GYRO 4Gyro-4 (skew) autonomously selected because of switch to YGC mode
09/12/200308:35:19 Spacecraft autonomously swapped to YGC Attitude Control Mode.
10/02/200216:30:00 Select primary roll/yaw coil
10/02/200216:29:00 ADACS to nominal mode
10/01/200215:13:00 Turn IMU override off. Allow autonomous gyro switching.
10/01/200215:12:00 Force override to select orthogonal gyros (XYZ).
09/30/200220:21:00 Enable roll/yaw coil switching. Clear yaw gyro hardware bias.
09/28/200213:11:00 Loads control CPU ephemeris for day 268
09/28/200200:00:00 Expired Ephemeris caused attitude anomaly
07/22/199800:00:00 Correction to roll error loaded to spacecraft
04/14/199800:00:00 ADACS commanded to Nominal mode
10/18/199700:00:00 Several abrupt shifts in roll gyro rate output indicating shifts in spacecraft yaw position.
08/22/199700:00:00 ADACS mode switch to Yaw Gyro Compassing due to low sun angle
02/13/199700:00:00 Negative roll error of 0.339 degrees observed in AVHRR processed image .
02/14/199500:00:00 Yaw correction was loaded to correct yaw error in AVHRR.
10/21/199200:00:00GYRO 4Skew Gyro mean rate output changed erractically and continues unstable. Exercised self-tests to recover stablility.
03/26/199200:00:00 Yaw error of 0.4 degrees has been observed in AVHRR processed images during ADACS nominal control mode.
05/14/199115:26:00PTC 2BOn Orbit
05/14/199115:26:00PTC 1BOn Orbit
05/14/199115:26:00PTC 1AOn Orbit
05/14/199115:26:00IMUOn Orbit
05/14/199115:26:00GYRO 3On Orbit
05/14/199115:26:00PTC 2AOn Orbit
05/14/199115:26:00RYTC 2BOn Orbit
05/14/199115:26:00GYRO 1On Orbit
05/14/199115:26:00GYRO 2On Orbit
05/14/199115:26:00RWA SOn Orbit
05/14/199115:26:00RWA XOn Orbit
05/14/199115:26:00RWA YOn Orbit
05/14/199115:26:00RWA ZOn Orbit
05/14/199115:26:00RYTC 1AOn Orbit
05/14/199115:26:00RYTC 2AOn Orbit
05/14/199115:26:00SSAOn Orbit
05/14/199115:26:00GYRO 4On Orbit
05/14/199115:26:00ESAOn Orbit
05/14/199115:26:00RYTC 1BOn Orbit