NASA Announces Repair Plans for Aging Hubble Telescope
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GWEN IFILL: The $2 billion Hubble telescope vaulted into space aboard the Shuttle Discovery in 1990, and the spectacular images it’s beamed back to Earth ever since have captured the public imagination: enabling the earthbound to observe the universe as it was 12 billion years ago; peering into black holes at the center of galaxies; and observing the oldest burned-out stars in the Milky Way, colliding galaxies and roiling caverns of dust and gas.
Today’s NASA announcement will extend the Hubble’s life by several years. To discuss the history and future of the space telescope, we are joined by David Leckrone, Hubble senior project scientist.
DAVID LECKRONE, Hubble Senior Project Scientist: Thank you.
GWEN IFILL: So what is it about the Hubble telescope which, as I described, has captured the public’s imagination all these years?
DAVID LECKRONE: Well, I think there are many reasons, but perhaps the simplest is that it’s given the first clear view to humankind of what the universe really looks like.
I think we’re all very curious about where we’ve come from and where we’re going. We’re all attracted to the night sky, and what’s up there, and what’s beyond the next star. I think that at heart we’re all Trekkies, and although we can’t literally fly across the universe in a Starship Enterprise, the Hubble can take us across the universe as a vicarious trip.
And I think ultimately, though, Hubble has just inspired people from all walks of life. And I think it also makes Americans very proud, that this is something positive that we have accomplished as a people.
Deciding to service Hubble
GWEN IFILL: OK, as one Trekkie to another, why was this decision made today to extend this mission?
DAVID LECKRONE: Fundamentally, the Hubble was originally designed to be launched and serviced by the space shuttle, by astronaut crews in space suits going out on spacewalks. And we have done that fully successfully four times in the past. We've had 18 completely successful extravehicular activities, EVAs, on past missions, but those missions were accomplished during a period of time when we didn't realize what the threats to safety within the space shuttle itself were.
And after the Columbia tragedy, that was a very sobering experience, horrifying experience for all people who work for NASA. And the NASA administrator, Sean O'Keefe, at that time elected to cancel the final servicing mission to Hubble out of genuine concern and unanswered questions about the future safety of shuttle flights.
GWEN IFILL: So have those questions now been answered?
DAVID LECKRONE: I think to a very large degree they have. I think Administrator Mike Griffin set a very high standard and defined a decision-making process that had great integrity to it.
He used to work on Hubble 20 years ago. And, of course, he loves Hubble, as we all do, and what it's accomplished for humankind, and so he has stated on many occasions in public that he would like to find a way to service Hubble if it were possible to do it safely.
Hubble sheds light on black holes
GWEN IFILL: So, in all of the years that the Hubble has been in space, what have we learned? For instance, I mentioned in the introduction the existence of black holes. What's significant about that?
DAVID LECKRONE: Well, of course, black holes weren't even proven to exist up until, say, the 1990s, and Hubble played a very major role in getting the first concrete existence proof that supermassive black holes exist at the center of galaxies.
The interesting thing is that scientists, for a number of years prior to that time, had really believed in their heart of hearts that there were supermassive black holes at the centers of galaxies, but they just couldn't prove it with ground-based telescopes. And this is one of many examples where Hubble, upon getting this much clearer view of the universe, and particularly the central regions of galaxies, was able in relatively straightforward way to show that supermassive black holes are there and to actually measure how massive they are.
One of the conclusions of that was that Hubble did what I call the first demographic survey of black holes, examining many different galaxies and showing that the bigger the galaxy, the bigger the black hole; the smaller the galaxy, the smaller the black hole. So nature is telling us something here about how galaxies form and how black holes form and how there's a relationship between those two things.
Difficulties of repairing Hubble
GWEN IFILL: So when the scientists, the astronauts go back up with the next shuttle mission for this Hubble repair job, what exactly are they doing? I read somewhere today that one of the telescopes they have to repair involves taking 100 tiny screws off of the outside of a case in order -- in space. How do they do that?
DAVID LECKRONE: Well, that's very -- that's really a cool thing. The space telescope imaging spectrograph is a very powerful instrument that was placed onboard Hubble in 1997 during our second servicing mission, and it is widely used, very heavily used by astronomers. It's a very versatile instrument.
Basically, it has the capability to take light from sources out in the cosmos -- galaxies or stars or comets or whatever -- spread that light out into its component rainbow of colors, and then, by measuring how bright the different colors are, you can learn a lot about what objects are made of, how hot they are, how fast they're moving. So an extremely important scientific instrument that failed in 2004, the latter part of 2004.
So what we have tried to develop is a technique for perhaps repairing that instrument while it's still within the Hubble space telescope itself. We've never done that before; that is, open the payload bay doors of the Hubble, going inside, removing a panel from the side of an instrument.
And in this case, we have to remove 111 screws to get that panel off. I say "we"; of course, these are astronauts in spacesuits with big, heavy gloves. So they have to remove this panel, having removed all of those screws, and then they have to go in and carefully pull out a failed electronic circuit board, and replace it with a new board, and then close it all back up again.
Future Hubble operations
GWEN IFILL: If all of that works -- and this is a very delicate exercise you're describing -- and you were able to extend the life of the telescope, how much longer will it be able to operate and what more will we be able to see?
DAVID LECKRONE: We are nominally shooting for an additional five years of lifetime, with this mission to be carried out sometime in the springtime of 2008. So we're hopefully going to about 2013. The way these things normally work, perhaps we'll be able to go a bit longer than that.
But in that period of time -- and I should make this especially clear -- after the astronauts leave, after servicing mission four in 2008, Hubble will be at the absolute apex of its capabilities. There never will have been a time in its past history when it has been as powerful a scientific tool as it will be at that point.
This is in large part due to the fact that we're putting two very high technology new scientific instruments onboard Hubble, a new camera that's capable of surveying the universe to very great depth over a very wide range of colors, from the ultraviolet, which is blocked by the Earth's atmosphere, to the near-infrared, which is impeded by the Earth's atmosphere, and all of the range of colors and wavelengths in between.
And a cosmic origin spectrograph that will be the most sensitive device of its type ever placed in orbit. And, therefore, we'll be able to look farther out across the universe and take these rainbow-of-color measurements on objects much farther away than we've been able to do in the past.
GWEN IFILL: Well, we will all be waiting and watching. David Leckrone of NASA, thank you very much for joining us.
DAVID LECKRONE: You're quite welcome. Thank you.