Yeah, probably because it had a tracking device on board
That's what they did the last time to be able to "find" it.
Plus, this whistleblower got fired for exposing the fraud behind this boondoggle earlier:
Penalty was steep for NMD whistle-blower
"Last week saw the release of a report from the General Accounting Office that details how the Pentagon, two major military contractors--TRW and Boeing--and a team of MIT scientists exaggerated the success of the nation's first missile defense test, turning an embarrassing failure into a phony triumph."
http://www.latimes.com/news/printedition/opinion/la-000019022mar15.story