Hitomi was an Astrophysics science satellite in LEO with four X-ray telescopes, for imaging and spectroscopy of soft and hard X-rays. A paper based on some of the data collected during it's short operational life was just published in Nature.
This JAXA Press Release links to this JAXA PDF.
edit: Here is the June 8, 2016 updated JAXA PDF, much longer and more thorough. There is also a brief synopsis in Nature, but I'm not sure if it is reliable - the title, "Software error doomed Japanese Hitomi spacecraft" is misleading to say the least.
Just as in aviation and transportation, an understanding and reporting of events and issues leading to loss of spacecraft is invaluable to the entire community to help avoid losses in the future. Space is hard.
For example, I give several links to the two near-loss and recoveries of SOHO in 1998 here, including the thorough Roberts 2002 report. There were many lessons learned there.
Can someone help summarize the JAXA report here to an easier to understand, if less precise explanation? It seems to be a combination of things, instructions, maneuvers, design, stresses... Could it be said that a realistic worst-case scenario was simply not properly anticipated?