As the number of space elements increases, space communications enter a new era, where internetworking gradually replaces traditional telecommunication protocols. Delay Tolerant Networking (DTN) has emerged as the most prominent solution for such challenged networks; however, extensive testing and evaluation of all mechanisms is required prior to the wide deployment of DTN. In this paper, we present our experiences from architecting a state-of-the-art DTN testbed, capable of emulating future space communications and appropriate to evaluate proposed protocols and mechanisms. Several evaluation results have been drawn so far, including reliability (CFDP over LTP), routing (Contact Graph Routing versus other DTN routing protocols) and interoperability issues (communication between DTN and Space Packet nodes).