So this is a little like a little mirror that's aiming at you
all the time, regardless which way you're looking at it.
My name is Xiaoli Sun.
I'm a LIDAR instrument scientist.
I also work on other laser instruments.
The instrument is a laser retroreflector array.
It's a small retroreflector mounted
on the shell, on the aluminum shell support shell.
A retroreflector reflects laser light back to where it came from.
The purpose is to number one, to have a
fiducial marker, a precise fiducial marker on the lander
so that we know exactly where that is on the lunar surface.
It serves as a landmark
for future missions If you want to go back and land there.
When you shine a laser on it, it reflects right back at you.
So it doesn't matter which way you're looking at it.
And so that will help us to range
from orbit to the lander as it passes overhead.
Payload Services, NASA and American companies work together.