The necessity of ground-based data to Euclid’s scientific success provides a potential basis for negotiating agreements between the ground-based projects and the Euclid mission, which could lead to increased U.S. scientific participation in Euclid. The Department of Energy and the National Science Foundation are the predominant sources of support for two of the U.S.-led ground-based projects, the Dark Energy Survey and the Large Synoptic Survey Telescope. The degree to which these agreements might be coordinated with the proposed NASA participation in Euclid is a matter that the Astronomy and Astrophysics Advisory Committee, which is charged with considering interagency issues, could consider.

Obtaining the full scientific benefits of the combined ground- and space-based data will likely require joint processing and analyses of the combined data sets at the pixel level. This deep level of engagement in the data argues for direct collaboration between the ground- and space-based projects. Such joint analyses would require significant data management resources that are not currently budgeted within these projects.