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Our Window to the Stars

Season 1Apr 19, 2020

Decades of planning. One heart-pounding setback. Over a million mesmerizing images of space. This is the story of the Hubble Space Telescope, our window to the stars.

NASA's Curious Universe

Introducing NASA’s Curious Universe

Our universe is a wild and wonderful place. Join NASA astronauts, scientists and engineers on a new adventure each week — all you need is your curiosity. Visit the Amazon rainforest, explore faraway galaxies and dive into our astronaut training pool. First-time space explorers welcome.

About the Episode

Decades of planning. One heart-pounding setback. Over a million mesmerizing images of space. This is the story of the Hubble Space Telescope, our window to the stars.


[NATURAL SOUND: Crickets and frogs make noise late at night by the river]

HOST: We all know what it’s like to wander outside and look up at the night sky. On a clear night, when you can see all of the stars perfectly… it’s so easy to feel small.


HOST: It makes you wonder… what’s out there, beyond what we can see? The Hubble Space Telescope has helped us answer that question over the last 30 years,revealing that reality is often stranger than fiction.

NASA's Curious Universe

HOST: With Hubble, we’ve learned all about the age of galaxies and the rapid expansion of our universe. We’ve seen the births and deaths of stars… and we’ve found answers to questions we’d never even thought to ask before! We’ve learned all of this in incredible detail… By looking back in time.

JENNIFER WISEMAN: Hubble is like a time machine in the sense that we can look farther and farther out into the universe at these fainter and fainter more distant galaxies. And by doing that, we’re really looking back in time because it has taken time for that light to get to us from these stars and galaxies…

HOST: That’s Jennifer Wiseman. She’s the Senior Project Scientist for Hubble, and says that the telescope is achieving more than scientists originally expected.

JENNIFER WISEMAN: Hubble has recently contributed to the determination that the expansion of the universe is in fact accelerating. That was unexpected. Hubble has become the pioneering telescope in analyzing the atmospheres of exoplanets. Hubble has found the likely presence of water and moons around other planets using interesting innovative techniques… that was really not something Hubble was originally designed for. So we’re using Hubble now for the kinds of science we did not originally anticipate…

HOST: And after all this time, the discoveries we get from Hubble every day are still knocking us back, telling us more about the nature of our universe and its origins.

HOST: But Hubble’s journey to the stars was a difficult one. So how did it succeed?


HOST: Welcome to NASA’s Curious Universe. I’m Padi Boyd, and in this episode, we’re exploring a truly iconic NASA mission, the Hubble Space Telescope, our window… to the stars.This is the story of how NASA put a telescope… into space.


HOST: Decades before the Hubble Space Telescope was even a possibility, the idea of looking beyond our own atmosphere was at the forefront of astronomy. Back then, most astronomers believed that the universe consisted of just one galaxy, our own Milky Way.

HOST: Then, Edwin Hubble came along… and changed everything.From a mountain top near Los Angeles, he peered up at the night sky with a ground-based telescope… The Hooker telescope, which, at the time, was the largest one in the world!

HOST: That’s when he spotted something amazing: the fuzzy objects he noticed in our sky were actually other galaxies. And most of the galaxies he spotted looked like they were moving away from each other.

JENNIFER WISEMAN:… Edwin Hubble was one of the pioneers that determined that our universe is in fact expanding galaxies seem to be moving apart from each other, along with that stretching of space. But we couldn’t quite discern the rate of that expansion. It’s a very difficult measurement.

JENNIFER WISEMAN: So the Hubble Space Telescope was able to contribute to a really higher precision measurement of that expansion rate by measuring more carefully the distances of these galaxies, and correlating that with other measurements of their apparent velocities, and giving us an expansion rate that was much more refined than anything ever before…

HOST: Edwin’s discoveries made scientists wonder: if we could see all of that from aground-based telescope, what would happen if we sent one above our murky atmosphere? German scientist Hermann Oberth dreamed of what we might learn:Archival: “If we could look at the heavens with an astronomical telescope in orbit, unhindered by the shielding sea of atmosphere that blankets the earth, think of the discoveries we would make– the clear vision of the universe we would have.”

HOST: Echoing Oberth’s vision, Astronomer Lyman Spitzer outlined details for how to make it all work in an academic paper that would really set the stage for Hubble’s creation. So NASA set out on an adventure… to place a telescope in space.

HOST: This telescope would discover things that would revolutionize the way we think of our place in space…But don’t just take it from me. Here’s what the great Astronomer Carl Sagan had to say about this bold experiment.


[CARL SAGAN: Space Telescope is, in a way, a little like Galileo’s first telescope. Wherever Galileo pointed his telescope, he made major new discoveries. Look at the Moon, you find mountains and craters, look at Saturn, you find rings, look at the Milky Way, you find it is littered and composed of Stars. Every one of these discoveries, things that people had not known before. I think it’s going to be very similar with the space telescope. It will illuminate celestial objects that we know about, it will discover celestial objects never before guessed, it will provide insights into the most important questions such as stellar evolution, such as the search for planets going around other stars, and the grandest cosmological questions of the origin, nature and fate of the universe. Space telescope is a kind of grand intellectual adventure for all of us which will cast light not just on the cosmos but on ourselves…]

HOST: The telescope was built at Lockheed Martin in California, with NASA’s Marshall Space Flight Center overseeing the telescope’s construction. It was named after Edwin Hubble, who paved the way for grand discovery.

HOST: But actually getting a telescope the size of a school bus into space is difficult, as you might imagine.

HOST: That’s where the Space Shuttle Discovery comes in! NASA’s space shuttles were designed to carry and deploy spacecraft like Hubble. With the Space Shuttle Discovery, NASA would deploy Hubble at the edge of space, in low orbit, and returnsafely to Earth. NASA designed the telescope to fit snuggly inside Shuttle Discovery, which carried and released this precious cargo into space.

[NBC NIGHTLINE’s CHRIS WALLACE: The Shuttle Discovery, poised at Cape Canaveral for launch tomorrow morning. It may be the most ambitious and eagerly awaited mission in the history of the Shuttle program. Onboard, a giant telescope thatwill redefine our view of the universe…]

HOST: When it launched in 1990, NASA’s Hubble Space Telescope was only designed to last 15 years. In 2020, the telescope celebrates its 30th birthday — and Hubble is still as strong as ever.

MICHELLE THALLER: Hubble makes discoveries 24 hours a day. It’s up there orbiting the earth and it goes around the earth about once every 90 minutes.

HOST: That’s Michelle Thaller, an astronomer and science communicator at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Goddard is home to Hubble’s mission control.

MICHELLE THALLER: The Hubble Space Telescope is something that just changed everything. I think people now have this view you know–what does space look like? And they don’t even realize that what they are thinking of is something that Hubble images brought to our culture and to our imagination…

[MUSIC: Everything’s Connected by Lee Rosevere]

HOST: She’s right. When you close your eyes and imagine space, you probably picture stars, beautiful colors and a sheer vastness. The images that pop into your head are probably star-studded and full of the colorful clouds of nebulas. That’s because the pictures taken by the Hubble Space Telescope are the clearest and closest we’ve ever come to looking at our universe. They’ve fundamentally shaped how we think of space.

HOST: And from space, Hubble can see a lot.Here’s one way of looking at it… Imagine going to a piano concert and the musician sits down and can only play three notes around middle C.

[NATURAL SOUND: A pianist plays just a few piano keys]

HOST: That’s the amount of light we can see here on Earth.

[Piano continues]

HOST: Then, there’s a whole spectrum of light our eyes aren’t sensitive to and that’s where Hubble comes in. Hubble can see in multiple wavelengths of light, like infrared and ultraviolet. So Hubble’s view would sound a lot more… like a symphony![MUSIC: Chopin Etudes Op. 10 No. 1]HOST: NASA made a huge push in the years leading up to Hubble’s launch to promote the revolutionary telescope’s efforts. NASA’s expectations promised the public that this project would lead to important discoveries and answers. This was the culmination of decades of work and research, not to mention the financial and emotional investments riding on this mission. On April 24, 1990, the telescope launched.

Archival: 5…4…3…2…1 and liftoff of the Space Shuttle Discovery with the Hubble Space Telescope, our window on the universe.

HOST: Back on Earth, mission control monitored the deployment carefully. The crew understood what was at stake.

Archival: And this is Hubble Telescope Control in Greenbelt, uh… we have been given the go-ahead to begin commanding the release of the forward latches, which hold the solar arrays in place during launch along the side of the telescope.HOST: When the Discovery crew set out to deploy the telescope, they were under a lot of pressure. After all, Hubble was set to be the greatest astronomical advancement since Galileo’s own telescope. But something went wrong.


MICHELLE THALLER: Of course, when Hubble finally got up and everybody was really excited, there was this amazing sense of deflation when they opened up the telescope, light went through it and they realized the images were out of focus and they were out of focus because the curvature of the mirror was wrong… So I mean, this was just an incredible mistake. I mean people had been making very accurate telescope mirrors for a very long time and the fact that… all of a sudden, up in space… What were we going to do now? This incredibly valuable instrument was launched and there was just this tremendous problem.

HOST: The first pictures that NASA saw down here were fuzzy and distorted. And it was all because of an incredibly small, almost undetectable aberration in the lens… a tiny error from when the mirror was constructed. Hubble’s vision… was blurry.HOST: But the telescope was still technically doing its job, at least as far as astronomers like Michelle were concerned.

MICHELLE THALLER: The spectrograph still worked just fine! [Laughs] The images were out of focus. But all of the data, you know, the really detailed data about the universe was still coming in through these spectroscopic instruments. So for people specifically doing my science, Hubble started working beautifully. We were making incredible discoveries…But of course, we wanted to get those clear images, to see the universe without the distortions of the atmosphere, to see it beautifully, beautifully clear.

HOST: From the beginning, Hubble was designed to work hand in hand with the Space Shuttle program.

HOST: NASA had anticipated that Hubble would need to be modified, and expected tosend astronauts to do so in the coming years…

JENNIFER WISEMAN:…What was not anticipated was that the first images coming from the Hubble Space Telescope were quite disappointing. There was obviously a problem…

Archival of DOUG BROOME: The conclusion we’ve come to is that there’s a significant spherical aberration appears to be present in the optics…

JENNIFER WISEMAN: The mirror on Hubble had been ground beautifully, but to a slightly incorrect formula and this had not been caught in testing.

MICHELLE THALLER: This incredible idea was raised: why don’t we fix it? And then this is one of the grand adventures of NASA.

HOST: NASA set out on a daring rescue mission… to save the Hubble SpaceTelescope.

JENNIFER WISEMAN: They came up with a very insightful solution. Basically putting,in some sense it’s been described as putting glasses on Hubble.HOST: These “glasses” were actually an instrument, which was designed to correct Hubble’s flaw. A team of astronauts were prepared to service the telescope… in space.

[ARCHIVAL SM1: Hello Houston! We are ready. We are Inspired. Let’s go fix this thing!]

[Sounds like a good plan, endeavor, good morning!]

MICHELLE THALLER: They made an instrument that actually corrected the light before it went into cameras, took out the curvature…Archival: Okay… I’m in one inch, you’re in one inch, and I have it, and you have it…yesI have it. Okay, I’m going to let go…

MICHELLE THALLER: all of the sudden everything snapped into beautiful, beautiful focus.


MICHELLE THALLER: Everything was gorgeous. So it is one of the most amazing happy endings in the history of science, in the history of technology. HOST: Hubble’s servicing missions didn’t stop with its initial rescue.HOST: Over the years, Hubble has been serviced multiple times. John Grunsfeld is one of the astronauts who helped keep Hubble in top shape.

JOHN GRUNSFELD: For me as an astronomer, going out in a space suit and working on Hubble was the ultimate experience. There’s nothing cooler. Hubble is such an icono f science and to me, it was the holy grail of being an astronaut.

HOST: John worked on three repair missions to the telescope, earning the nickname “Hubble’s Keeper” from publications like The New York Times.

JOHN GRUNSFELD: I was expecting, you know, the wonders of space and the beauty of the Earth, but what surprised me the most was that I kind of discovered my humanity. Being in a tight crew, working together as a team, with hundreds of thousands of folks on the ground…there’s really nothing that humans can’t achieve if we work together as a team and if we have good challenges, things that are worth doing. We can do almostanything.HOST: We know so much about our universe now because of people like John, people who were watchful stewards of the telescope and who dedicated themselves to its success.

JENNIFER WISEMAN: We thought Hubble might last 10 or 15 years if we were lucky.But thanks to the series of astronaut servicing missions over the years, the telescope has been refreshed over and over again with repaired instruments and new batteries and gyroscopes and things like that, refreshed, new instruments as well. And that has made the telescope basically brand new, more or less every time we’ve done a servicing mission, and that’s kept it at the forefront of scientific discovery…

To get a look at the outstanding imagery from the Hubble Space Telescope, You can also follow the telescope on social media @NASAHubble.

This is NASA’s Curious Universe. The Curious Universe team includes Elizabeth Tammiand Micheala Sosby. Our Executive Producer is Katie Atkinson.Special thanks to the Hubble Space Telescope team.If you’re enjoying Curious Universe, consider leaving a review on your podcast app or tweeting about the show @NASA.And… in the next episode, astronaut Nick Hague takes us to an underwater training ground.

[Water sounds]