now, explain why gpl is so important, why is that so important? >> gpl is designs spacecraft that go to the planets and also does earth observations and astrophysics and well. >> stephen: and you are the guys controlling it once it gets on the planet or gets around the planet or something like that? >> that's right. >> stephen: and astronauts they get all the ticker tape parades and i love them and i want to be one, but you guys are the guys who are humping it day and night, year after year to learn things about our solar neighborhood, right? >> that's right. >> stephen: do you ever get angry at those guys? >> no, we are having too much fun. >> stephen: how did you get into doing this? >> actually, i was a graduate student in the, when the space-age began so i was there at the beginning and i have been doing these things now for over 50 years. >> stephen: now, we have a little, a video right here, this is the voyager spacecraft being launched, what year are we talking about here? >> we launched two spacecraft in 1977 and that was a very special ye