Heike made outstanding contributions to the H.E.S.S. experiment on topics bridging various working groups, from instrument, via analysis and reconstruction to the Extragalactic science working group. She was co-leading an effort to solve a large discrepancy at low energies between the two Monte-Carlo simulation chains that are used in H.E.S.S. Understanding this discrepancy ultimately allowed us to analyse and publish the high-impact paper on the Vela Pulsar emission observed with the H.E.S.S.-II telescope. Heike also shaped the H.E.S.S. target-of-opportunity programme in a major way, which is now one of the cornerstones of the H.E.S.S. science operations in the multi-messenger era.