1 00:00:00,010 --> 00:00:01,880 [ Music ] 2 00:00:01,900 --> 00:00:08,680 I'm Jan McGarry, I'm a mathematician and I work in the Laser Remote Sensing branch at the Goddard Space Flight Center. 3 00:00:08,700 --> 00:00:12,810 Satellite Laser Ranging is a technique of measuring the distance to the satellites. 4 00:00:12,830 --> 00:00:18,340 The light goes up to the spacecraft, bounces off, comes back, and that's the round-trip time of flight. 5 00:00:18,360 --> 00:00:24,500 And it's used both for very precise orbit determination, as well as once you've got the orbit nailed down 6 00:00:24,520 --> 00:00:30,880 then you can very precisely determine the location of where the center of mass of the Earth is and how it's moving. 7 00:00:30,900 --> 00:00:38,180 And then from the standpoint of the station location, the position of the stations in reference to one another 8 00:00:38,200 --> 00:00:45,400 give you indications of how the tectonic plates are moving with respect to each other. 9 00:00:45,420 --> 00:00:48,280 Goddard is actually the birthplace of Satellite Laser Ranging. 10 00:00:48,300 --> 00:00:54,780 It was developed by Henry Plotkin in the early 1960's when lasers were just first starting. 11 00:00:54,800 --> 00:01:02,480 He also developed the Satellite Laser Ranging ground station, which was the Goddard Laser Ranging Station, or GODLAS for short. 12 00:01:02,500 --> 00:01:06,360 And in fact we're coming up on the fiftieth anniversary of Satellite Laser Ranging here, 13 00:01:06,380 --> 00:01:12,180 because that was done October 31, Halloween, 1964. 14 00:01:12,200 --> 00:01:15,940 During a typical day I spend a lot of my time at meetings. 15 00:01:15,960 --> 00:01:21,480 But at night I'm often at the optical site operating the system, doing software development, 16 00:01:21,500 --> 00:01:26,580 or working on the automation of the Next Generation Satellite Laser Ranging system. 17 00:01:26,600 --> 00:01:31,550 When you do R&D development you run into a lot of dead ends sometimes 18 00:01:31,570 --> 00:01:36,030 and you run into a lot of problems that seem very difficult to solve. 19 00:01:36,050 --> 00:01:39,080 That's one of the reasons why Goddard is such a great place to work. 20 00:01:39,100 --> 00:01:45,920 People don't take no for an answer, when they find a problem they work very hard to solve it and get past it. 21 00:01:45,940 --> 00:01:50,730 [ Music fades ] 22 00:01:50,750 --> 00:01:59,900 [ Satellite beeping ]