Gastelaars was a Manticoran citizen and professional administrator.
In 1890 PD, he served as the senior administrator of the Unicorn Eleven space habitat in the Manticore System's Unicorn Belt. He organized a ski trip to the Athinai Resort on Gryphon for the children of his employees, including his own daughter, Monica. Unfortunately, the Resort was hit by the Attica Avalanche while the children were there. (HHA2.4: THWH)