End of Beyond Einstein?
LISA was a plan to send 3 spacecraft in formation to detect hypothetical gravity waves. IXO evolved from CON-X, a Space-based X-Ray observatory. These were considered first priorities in the Beyond Einstein program, yet in 2007 were pushed out of line in favour of a Joint Dark Energy Mission (JDEM). In August 2010 JDEM was itself replaced by WFIRST, which would seek extrasolar planets and look for DE on the way. November brought news that the entire astrophysics budget would be eaten by cost overruns on the James Webb Space Telescope.
The WFIRST Progress Report lists as its third goal, "Supernovae as a probe of the expansion history." No explicit mention of "dark energy," which many doubt even exists. The DE advocates are reduced to sub-committee advisors in this Powerpoint plan. WFIRST is described by Steinn as "a hack of a powerpoint presentation no one else had seen." There is reason to doubt that JDEM, WFIRST or anything similar will ever fly.
Is this the end of Beyond Einstein? No by a long shot! These missions would be expensive and not launch until years in the future. The case for existence of gravitational waves is questionable--the LIGO experiment has not detected any. The evidence for "dark energy" is even shakier; the redshifts of Type Ia supernovae can be explained by GM=tc^3 and a changing speed of light. The real advances may have been accomplished with little more than pen and paper.
The local conditions of Special Relativity, which do not allow for gravity, can be linked with the curved Space/Time of General Relativity. The solution can explain much about the Universe--its size, expansion rate and whether that expansion will stop or reverse. A bit of math can explain the non-linear increase of supernova redshifts, the cosmic horizon problem, the "flatness" problem, even the 4.507034% proportion of baryons. Long before the expensive Space missions would have launched, we may already be Beyond Einstein.