Background <p>Multi-layer tensioned membrane structures offer order-of-magnitude mass savings compared to rigid-deployable structures for spacecraft. Example applications include deployable sunshields and RF apertures like reflectarrays or phased arrays. However, these applications have tight shape accuracy requirements and benefit from precise measurement during ground testing to verify their planarity and membrane layer separation. There are currently no techniques for measuring full-field multi-layer membrane deformation in a laboratory environment.</p> Objective <p>We propose a new metrology technique using Digital Image Correlation (DIC) with a combination of UV and visible inks and light sources to fully reconstruct two parallel tensioned membranes. The technique is also used to obtain full-field separation data between the membrane layers.</p> Methods <p>Five sets of validation tests were performed to assess the technique and quantify sources of systematic error and experimental uncertainty. The technique was also applied to an example problem comparing the mechanics of scalloped and square membrane pairs.</p> Results <p>The technique was determined to have an out-of-plane precision of less than 50 µm, equivalent to twice the membrane thickness and only 0.5% of the membrane separation distance. The in-plane resolution was 0.95 mm. We showed that scalloped membranes maintained a more consistent separation across varying loads than square membranes.</p> Conclusions <p>The technique enables full-field multi-layer membrane reconstruction. It is proven for two layers and extendable to more layers by using different inks, light sources, and filters.</p>