&gt;&gt;&gt; THIS SUMMER WILL MARK THE
50th ANNIVERSARY OF NASA'S
APOLLO MISSION WHEN NEIL
ARMSTRONG BECAME THE FIRST HUMAN
BEING TO EVER SET FOOT ON THE
MOON.
HE PLANTED A FLAG ON THE MOON
SOIL.
HARRY SMITH HAS OUR SUNDAY'S
CLOSER.
&gt;&gt; Reporter: SUNSETS IN NEW
MEXICO RARELY DISAPPOINTS, NO
WONDER THEY CALL THIS THE LAND
OF ENCHANTMENT.
UP IN THE MOUNTAINS, THE BIG
TELESCOPE AT APACHE POINT
OBSERVATORY STARTS TO RING INTO
ACTION.
ONCE IT GETS DARK, WATCH OUT.
A POWERFUL LASER BEAM SHOOTS
INTO THE SKY AIMED AT THE MOON.
THE REASON?
THANKS TO FOLKS THAT WALKED UP
THERE.
&gt;&gt; I WAS STROLLING ON THE MOON
ONE DAY, ALONG WITH PICKING UP
ROCKS AND PLANTING FLAGS AND
HITTING GOLF BALLS, THEY LEFT A
FEW THINGS BEHIND.
&gt;&gt; Reporter: THAT RIGHT THERE
ABOUT THE SIZE OF A LAPTOP IS A
REFLECTOR WHICH A LASER BEAM IS
HITTING TONIGHT.
DR. McMILLAN IS A DOCTOR HERE.
&gt;&gt; WE CAN MEASURE TO THE
DISTANCE OF AN ACCURACY AS GOOD
AS A MILLIMETER.
&gt;&gt; MILLIMETER?
&gt;&gt; YES.
&gt;&gt; Reporter: THAT HELPS US
UNDERSTANDING GRAVITY WHICH
HOLDS A LOT OF STUFF TOGETHER
INCL
INCLUDING EINSTEIN'S THEORY.
&gt;&gt; IT IS HEAVY STUFF, I KNOW.
AMAZING THAT THREE U.S. LIU
MA
LUNAR LANDING MISSIONS LEFT A
REFLECTOR ON THE MOON.
&gt;&gt; SINCE THESE ARE THE ONLY
PIECES THAT'S LEFT ON THE MOON
THAT'S STILL IN USE, THEY DON'T
REQUIRE ANY POWER, THEY MUST
HAVE THOUGHT THAT'S A GOOD
INVESTMENT AT TIMES.
&gt;&gt; Reporter: THE MOON IS FILLING
ITS GRAVITATIONAL OBLIGATION,
THOUGH IT IS SLIPPING AWAY EACH
YEAR ABOUT AN INCH OR A HALF.
&gt;&gt; OKAY, HARRY, IF YOU PRESS
THAT GREEN BUTTON, IT WILL LET
THE LASER LIGHT OUT INTO THE
SKY.
&gt;&gt; IT WENT, CLACK, CLACK THAT
YOU CANNOT NOT HERE IT.
&gt;&gt; Reporter: STILL VERY
