Beyond Einstein program

The Beyond Einstein program is a NASA project designed to explore the limits of Einstein's theory of General Relativity. The project includes two space observatories, and several observational cosmology probes. The program culminates with the Einstein Vision probes, after completion of the Great Observatories program.

Constellation-X and the Laser Interferometer Space Antenna (LISA) have been promoted by NASA as the Einstein Great Observatories, to differentiate them from the current generation. However, they are not a part of the Great Observatories program.

Einstein Great Observatories

 * Constellation-X (HTXS) (Cancelled. Merged with Advanced Telescope for High Energy Astrophysics): the next generation X-ray space observatory
 * Laser Interferometer Space Antenna LISA (LISA Pathfinder in 2015): a gravitational wave space observatory. The NASA component of this mission was terminated in 2011; within the European Space Agency's Cosmic Vision Program, an evolved LISA has been chosen to proceed with a tentative launch date in 2034.

Einstein Probes
The science of the Dark Energy Probe was folded into the WFIRST mission upon recommendation by a National Research Council committee in 2010.
 * Inflation Probe: designed to examine the cosmic microwave background (CMB) polarization; a follow-up to COBE and WMAP
 * Black-Hole Finder Probe (BHFP): a complement to HTXS
 * Dark Energy Probe: the Joint Dark Energy Mission (JDEM) was studied extensively in three different implementations:
 * Supernova/Acceleration Probe (SNAP) - no longer under study. Superseded by the Wide Field Infrared Survey Telescope
 * Dark Energy Space Telescope (Destiny) - no longer under study. Superseded by the Wide Field Infrared Survey Telescope
 * Advanced Dark Energy Physics Telescope (ADEPT) - no longer under study. Superseded by the Wide Field Infrared Survey Telescope

Einstein Vision missions

 * Big Bang Observer, a follow-up mission to LISA and Inflation Probe, also a gravitational-wave observatory
 * Black-Hole Imager (MAXIM): an X-ray observation of infalling gas at the event horizon of a black hole; a follow-up to HTXS and BHFP