diff --git a/mission/controller/acs/FusedRotationEstimation.cpp b/mission/controller/acs/FusedRotationEstimation.cpp
index a818536f..bca5f190 100644
--- a/mission/controller/acs/FusedRotationEstimation.cpp
+++ b/mission/controller/acs/FusedRotationEstimation.cpp
@@ -18,6 +18,10 @@ void FusedRotationEstimation::estimateFusedRotationRateSafe(
       std::memcpy(fusedRotRateData->rotRateTotal.value, ZERO_VEC, 3 * sizeof(double));
       fusedRotRateData->setValidity(false, true);
     }
+    // store for calculation of angular acceleration
+    if (gyrDataProcessed->gyrVecTot.isValid()) {
+      std::memcpy(rotRateOldB, gyrDataProcessed->gyrVecTot.value, 3 * sizeof(double));
+    }
     return;
   }
   if (not susDataProcessed->susVecTot.isValid()) {