The SPICA Space Telescope
The SPICA Space Telescope is a proposed joint Japanese-European project to develop an advanced far-infrared space telescope. It will build on the experience gained from Herschel, but will include significant advances in detector and cryogenic technologies to allow it to be more than an order of magnitude more sensitive than Herschel - anything that Herschel can detect, SPICA will be able to obtain a spectrum of.
SPICA is currently a proposal to the Japanese Space Agency JAXA and to the European Space Agency as part of the Cosmic Visions programme. For more information see the JAXA SPICA pages.