Continued increase in performance and resolution for pointing and tracking hardware aboard spacecraft have required precise knowledge of their behaviour in, and response to, the thermal vacuum environment. This paper discusses acquisition of this type of knowledge by both line-of-site and interferametric methods. Results of the applications of both methods are reported, along with discussions of overall resolution and error, as well as possible difficulties which arise when these techniques are used. The line-of-site method is an autocol-limating technique employing digital theodolites. The interferanetric technique is an integration of off-the-shelf modular optical units into a multichannel laser interferameter. Both of the techniques are immune to movement between instruments outside the vacuum chamber, and targets inside.