JAXA is going to launch their next X-ray astronomy satellite. Designed specially to meet demands of Institute of Space and Astronautical Science (ISAS) ASTRO-H is sixth from satellites launched so far under the Mission of Opportunity in the Astrophysics Explorers Program, collaboration of NASA and JAXA. ASTRO-H will utilize hard X-ray telescope for imaging and spectroscopic observations of the space to help in the researches on universe structure. JAXA planned to utilize their HIIA rocket in this mission. It is reliable two stage rocket (only one failure comparing to 28 successful launches) with up to four solid fueled boosters and liquid fueled core stage. Due the fact that satellite weight is at 2700 kg it would be possible that JAXA will utilize H-IIA in 02 version with two boosters added and standard payload fairing.
UPDATE: Launch postponed due the poor weather conditions. New launch date is 17th February 2016.