Please define 'not lost'

Now this is funny..... as far as I know, 'lost' and 'don't know
where they are' are equal terms.......

NASA to Search Attics for Missing Moon-Walk Tapes
from the Seattle Times

WASHINGTON - Red-faced because the best pictures of its glory days are
missing, NASA said Tuesday it was launching an official search for
more than
13,000 original tapes of the historic Apollo moon missions.

What's missing are the never-before-broadcast, clear, original videos
- not
the grainy, converted pictures the world watched on television more than
three decades ago.

The tapes aren't lost, says the NASA official in charge of the
search. But
he doesn't know where they are. Most likely they are somewhere at the
sprawling Goddard Space Flight Center in Greenbelt, Md., which
misplaced the
tapes originally. But they also could be stored somewhere else.
http://seattletimes.nwsource.com/html/nationworld/
2003201902_moontapes16.htm
l

http://tinyurl.com/hgjye

look at defanition 1.1

Lost (lôst, lŏst) 
v.
Past tense and past participle of lose.
adj.
Unable to find one's way: a lost child.
No longer in the possession, care, or control of someone or
something: a lost pen.
No longer in existence; vanished or spent: lost youth.
No longer known or practiced: a lost art.
Beyond reach, communication, or influence: The expedition was lost to
the world for two months.
Not used to one's benefit or advantage: a lost opportunity.
Having not been or unlikely to be won; unsuccessful: a lost battle; a
lost cause.
Beyond recovery or redemption; fallen or destroyed: a lost soul.
Completely involved or absorbed; rapt: lost in thought.
Bewildered or confused: I'm lost—can you start over?