SCOTT SIMON, HOST:
August 25, 2003, NASA launched what's known as the Spitzer Telescope into space. Spitzer's orbited the sun for over 16 years, sending scientists images of wonders never seen before from our own and other galaxies. But now Spitzer has officially ended its mission. We're joined now by George Helou. He's one of the many scientists who's worked closely with Spitzer over the decades. He now serves as deputy director of the Spitzer Science Center at the California Institute of Technology. Dr. Helou, thanks so much for being with us.
GEORGE HELOU: Thank you, Scott, for having me. It's a pleasure to be here talking to you about Spitzer.
SIMON: Well, what did Spitzer see and send back to us here on Earth?
HELOU: So Spitzer saw pretty much every aspect of the universe that you can see in the infrared. And that means that it saw pretty much every object we knew about from objects in our solar system, comets and asteroids and planets to exoplanets. That was a big surprise that it was able to study exoplanets. An exoplanet is a phenomenon that is planets around other stars. It saw galaxies near and far. It saw - some of the earliest galaxies we know in the universe were discovered by Spitzer in combination with Hubble.
SIMON: And why is Spitzer shutting down now?
HELOU: It's a complicated mix of factors that fold into these decisions. And this decision was taken, actually, a while ago, like, two or three years ago by NASA. You know, they look at the mix of missions. They look at what is coming up. They look at how difficult it is to operate. It was becoming harder and harder because it's very far away from Earth. So a series of technical and problematic considerations led to the decision to stop operations at this point.
SIMON: When we launch a satellite, though, there's a certain life expectancy?
HELOU: Spitzer was expected to function for 2 1/2 years with liquid helium that is cooled - completely cooled and all of the instruments working. It - what happened was we got 5 1/2 years of cold operations with all the instruments. And we got more than 10 years of warm operations with just one of the instruments going, far exceeding the expectation.
SIMON: How do you think we see the universe differently because of Spitzer?
HELOU: The difference with Spitzer is that you are looking at infrared light. So it is light which our eyes cannot see. And that reveals a whole different aspect of the objects that you're looking at, the physics and galaxies, the physics in star-forming regions. Because of that, when I go out in the evening and look at stars in the sky, knowing what they look like with Spitzer gives me a much greater appreciation of the richness of the phenomena in the universe.
SIMON: You'll miss Spitzer?
HELOU: Yes. I think I will miss Spitzer. But I'm cheered by the prospect of the next generation of telescopes and observatories and how much more powerful and how they would build on the Spitzer insights and answer questions posed by the Spitzer results. There will likely never be anything quite like Spitzer. We never rebuild the same telescope. There will always be this sort of wistful feeling of, what is it we could have discovered with Spitzer that we are not going to discover because we stopped observing?
SIMON: When is the next great telescope being launched?
HELOU: We are expecting the launch of the James Webb Space Telescope. That is NASA-led. That is scheduled for sometime in 2021.
SIMON: George Helou is deputy director of the Spitzer Science Center in Pasadena. Thanks so much for being with us.
HELOU: Thank you, Scott.
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