The IEEE.802.15.4a standard has recently attracted much attention as an indoor short-range highspeed wireless communication. One of the most exciting characteristics of the IEEE.802.15.4a standard is that its bandwidth is over 500MHz which can satisfy an extensive range of space applications. Moreover due to its low power spectral density emission and its resistance to multipath, the UWB technology seems adapted for an intra-spacecraft application with hard electromagnetic compatibility constraints and presence of reflective spacecraft internal cavities. This paper presents an overview of the different BER simulations in presence of multipath and narrowband interference due to the spacecraft environment. This paper presents part of the work performed in the first phase of the activity covered by the UWB4SAT project (ESTEC/Contract No. 4000107142/12/NL/AK) with the objective to demonstrate the feasibility of an intraspacecraft UWB communication.