CONSTELLATION-X will be composed of several telescopes. It will allow unprecedented resolution in X-Ray images, allowing us to observe matter spiralling into Black Holes! For those who believe in such things, it will observe clusters of galaxies as probes for the amount and evolution of "dark energy." CON-X is considered the next priority after the James Webb Space Telescope.
Thanks to the human spaceflight vision, we will develop the ATLAS V launcher. That will give us heavy-lift capability like the old Saturn V. It will allow all of the CON-X spacecraft to be launched at once, decreasing the cost of the mission. Human and robot Space programmes can aid each other.
CON-X is part of NASA'S Beyond Einstein program, which also encompasses JDEM and LISA. Because of the Joint Dark Energy Mission, we must choose which will launch first. In his talk at the AAS HEAD meeting, Chief Scientist Harvey Tananbaum emphasised that CON-X and LISA are approved by NASA (and JDEM is not). He also emphasised that the technology for CON-X is mature.
The CON-X team has settled on a single concept for the mission. "Dark energy" researchers are divided among SNAP, DESTINY or ADEPT concepts. This excludes other worthy concepts, like JEDI, that did not make the cut. Speculation about "dark energy" does not lead to a true Theory, but to a divergence of ideas.
BTW, this author is also part of the NASA programme. We deliver presentations on research that goes Beyond Einstein. If any school or astronomy club wishes a lecture, contact me.