Japan launches its fourth <a class="mw-redirect" href="https://en.wikipedia.org/wiki/Spy_satellite" id="mwAYA" rel="mw:WikiLink" title="Spy satellite">spy satellite</a>, stepping up its ability to monitor potential threats such as <a href="https://en.wikipedia.org/wiki/North_Korea" id="mwAYE" rel="mw:WikiLink" title="North Korea">North Korea</a>.