1
00:00:13,713 --> 00:00:17,183
So this is a little like a little mirror
that's aiming at you

2
00:00:17,183 --> 00:00:20,186
all the time, regardless
which way you're looking at it.

3
00:00:20,253 --> 00:00:21,721
My name is Xiaoli Sun.

4
00:00:21,721 --> 00:00:23,857
I'm a LIDAR instrument scientist.

5
00:00:23,857 --> 00:00:26,559
I also work on other laser instruments.

6
00:00:26,559 --> 00:00:29,462
The instrument is a laser retroreflector
array.

7
00:00:29,462 --> 00:00:32,966
It's a small retroreflector mounted

8
00:00:32,966 --> 00:00:36,202
on the shell, on the aluminum
shell support shell.

9
00:00:36,403 --> 00:00:40,840
A retroreflector reflects laser
light back to where it came from.

10
00:00:40,907 --> 00:00:43,676
The purpose is to number one, to have a

11
00:00:43,676 --> 00:00:47,747
fiducial marker,
a precise fiducial marker on the lander

12
00:00:47,747 --> 00:00:53,853
so that we know exactly where that is
on the lunar surface.

13
00:00:53,920 --> 00:00:56,222
It serves as a landmark

14
00:00:56,222 --> 00:01:00,026
for future missions
If you want to go back and land there.

15
00:01:00,093 --> 00:01:04,230
When you shine a laser on it,
it reflects right back at you.

16
00:01:04,230 --> 00:01:06,800
So it doesn't matter
which way you're looking at it.

17
00:01:06,800 --> 00:01:09,636
And so that will help us to range

18
00:01:09,636 --> 00:01:16,876
from orbit to the
lander as it passes overhead.

19
00:01:19,287 --> 00:01:28,291
Payload Services, NASA
and American companies work together.