The High Energy Astrophysics Group has proposed for many space missions over the last 30 or more years. Many of them have been selected for development by NASA and flown successfully. Some, however, were not selected. This by no means meant that they did not have worthy scientific goals, state-of-the-art instrumentation, or excellent project teams. Generally they were deemed to be too risky --- either in the instrument development or the funding available -- and sometimes they just lost the competition to a better proposal, as judged by the scientific peer review, the technical, management, and cost review, and/or NASA management.
We present some aspects of those proposed missions in the Web pages with links to the right. CHIP, FARXITE, HEXIS, and GLAST/CMI are Cadmium Zinc Telluride (CZT) detector-based instruments utilizing either focusing optics with multilayers or coded mask imaging. The energy range covered by these missions begins below 10 keV and can range as high as 200 keV.