This work was based on the need for a relatively small passive detector of maximum temperature reached by an object that can be visually inspected. The device requirements are to be hermetically sealed for contamination control, give a clear indication of maximum temperature achieved (non-reversible) with a ~10 °C resolution, have an essentially unlimited shelf-life and insensitivity to radiation, be passive without any electronics or mechanisms, provide good thermal conductivity, and be low-cost. Prior detectors have an unclear lifetime, contamination outgassing properties, and radiation tolerance. These could be used at much higher temperatures than plastic methods (>>100 °C), though out of scope for the tests performed to date.
A device that permanently records the maximum temperature reached (47-70 °C) was tested, though other temperatures are possible. The low-cost device is hermetically sealed with no possibility of organic contamination, has an essentially unlimited shelf-life, is impervious to radiation damage, can function in any orientation or gravity, is unpowered, and passive. The device is read by visual inspection after opening the seal.
This work provides a metallic, robust, simple, non-reversible thermometer. The device features a commercial off-the-shelf (COTS) ultra-high vacuum flange with COTS eutectic metals and COTS Kapton tape. The design is flexible for space or non-space extreme environments where the temperature can be read optically, and can be used at much higher temperatures.
This work was done by Jason Dworkin of Goddard Space Flight Center. NASA is seeking partners to further develop this technology through joint cooperative research and development. For more information about this technology and to explore opportunities, please contact Scott Leonardi at