This contract supported on-going as well as planned research into environments and spacecraft interactions in near space. The major projects are summarized in this report. Models and geophysical data bases were investigated for spacecraft charging, shuttle contamination, electrostatic particle pushing codes, beam-plasma interaction in emitting probes, magnetospheric dynamics. Adiabatic invariance of trapped particles, fluxgate magnetometer simulation and falling sphere accelerometers. In support of the CRRES project, a data management plan has been provided, and a graphics capability was developed for the SPAN network. Software development was involved in all phases, using CYBER, VAX and RIDGE computers.