The German Aerospace Center (DLR) has greatly improved the website on the REXUS project. Now you can find there more detailled technical information as well as two videos of launch and recovery of a previous REXUS mission!
“The launch vehicle is composed of an Improved Orion motor with exhaust nozzle extension, a tailcan, three stabilizing fins and a motor adapter with an integrated separation system. See Figure 1. The total mass of the rocket is around 515 kg comprising a propellant mass of 290 kg, motor and vehicle hardware of around 125 kg and a payload mass of around 100 kg. The total rocket vehicle has a length of approximately 5.6 m depending on the size of the experiments and the diameter is 356 mm. The standard configuration of this payload comprises the recovery module, the service system, an ejectable nosecone and two experiment modules. The mass of each experiment module structure and bulkhead is approximately 5 kg. The total available mass for the student experiments is normally about 30 kg.” (DLR)