You are referring to the original flagship concepts of NASA's Astronomical Search for Origins Program (often shortened to the Origins Program), formulated in the mid-to-late 1990s.

You are referring to the original flagship concepts of NASA's Astronomical Search for Origins Program (often shortened to the Origins Program), formulated in the mid-to-late 1990s. While NASA’s earlier Great Observatories (Hubble, Compton, Chandra, and Spitzer) mapped the multiwavelength universe, this specific "Big Four" was envisioned to hunt for the first stars, trace the building blocks of life, and find Earth-like exoplanets.