PopSci Q&A: NASA Just Gave You A Telescope. What Will You Look At First?
For the first time, NASA turns over the reins to a functioning spacecraft
If you follow NASA at all, you know the agency has had some funding troubles of late, forcing changes to its manned spaceflight and Mars exploration programs. Among more high-profile woes, the strapped budget almost doomed one of the agency’s cheapest missions, the prolific Galaxy Evolution Explorer. But Chris Martin had another idea.
Yesterday NASA formally loaned the telescope to Caltech, the first time the space agency has turned over the reins to a functioning spaceborne asset. It may not be the last, however — if funding pressures persist, the GALEX experiment could pave the way for many future spacecraft adoptions.
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GALEX, an ultraviolet telescope, was supposed to last two years, and it’s been cruising in low-Earth orbit for nine years now. It was up for decommissioning in 2011, but Martin and members of the telescope’s science consortium were able to stretch that out another few months. Last November, he approached NASA’s Astrophysics Division to ask about taking on responsibility for the scope. This spring, the spacecraft was placed on standby mode and NASA gave the OK to transfer it. On Monday the space agency signed a formal agreement ceding control of the spacecraft.
“NASA sees this as an opportunity to allow the public to continue reaping the benefits from this space asset that NASA developed using federal funding,” said Paul Hertz, NASA’s Astrophysics Division director. “This is an excellent example of a public/private partnership that will help further astronomy in the United States.”
PopSci talked to Martin, the telescope’s principal investigator, about his pioneering idea, what GALEX has already told us about the universe, and his big plans for the telescope’s future.
PopSci: So who owns the telescope now?
Chris Martin: The original idea was to transfer the title, but that led to an issue of liability. In the end we actually solved it, because (builder) Orbital Sciences agreed to assume liability, but in the meantime, NASA figured out a different way of doing it through a Space Act agreement. That’s really a loan, so there is no transfer of liability. That worked out better for the president and board of trustees of Caltech.
PS: Why did you want to keep it running?
CM: It’s a small explorer, so it’s one of NASA’s smallest set of missions, about $100 million in development. Yet it’s been extremely productive scientifically with many interesting discoveries, ranging from stars in our own galaxy, to galaxies in the nearby universe that look like early young galaxies — “teenager” galaxies. There have been hundreds of papers from this telescope. So we felt very bad about shutting it down, and we knew we could operate it at very low cost.
My No. 1 issue was, we hadn’t completed the whole sky survey. With GALEX, there is no limit in the brightness we can look at. The Milky Way is very bright. A year ago, we tried out pointing the satellite at much brighter regions, and found the data is very high quality. So now we have the ability to essentially look in all directions of the sky. There’s about 20 percent of the sky, mostly in the direction of the Milky Way, to complete. That’s my No. 1 goal.
PS: What will this tell us about the cosmos?
CM: This [survey] is in the UV spectrum, centered around 2,000 Angstroms. It’s sensitive to hot massive stars as well as other sources of radiation which are not visible, or infrared, or other bands. It gives you a very different picture of, for example, a galaxy, or the evolutionary life of a star. To survey the remaining 20 percent would take about another 4 to 5 months. We’re still looking for support to do that.
PS: What else are you going to do with it?
CM: We have an international collaboration of 16 institutions, and they are interested in studying the history of galaxy evolution. One of the original purposes of GALEX was to study galaxy evolution in UV, and especially a region of the sky that is well served by other telescopes.
A group of Israeli universities [Weizmann Institute of Science, Tel Aviv University, Technion-Israel Institute of Technology, and the University of Haifa] are interested in studying the dynamic variable UV sky. When a black hole swallows a star, it produces this flash that lasts for many weeks. An object will suddenly become bright in UV, and that can mean that it’s a black hole in a distant galaxy, or it can also mean it’s a star exploding, a supernova. So we have a very exciting possibility of detecting the first moments of a supernova explosion, in a blinding UV flash.
Another partner is Cornell, and they’re interested in surveying the Kepler field. Kepler is looking at stars with transiting exoplanets, and UV provides incredibly important information for understanding the stars themselves, their variability, their star spots, as well as helping look for planets. So we’re finding multiple new science paths for GALEX.
There’s plenty of science remaining to be done, and at very low cost, about $100,000 per month. Compare that to the operations cost of other NASA missions, and it’s rock bottom.
PS: GALEX may not be as famous as spacecraft like Kepler or Hubble, but it’s done some pretty amazing things. What are some of its most important finds?
CM: We found that galaxies were much more actively forming stars 8 billion years ago than they are today. That’s one thing. It used to be thought that galaxies have a standard type, and we now understand that galaxies can change their types or qualities over cosmic time. A galaxy which may have been elliptical may have stopped forming stars, and become like a spiral galaxy, or a galaxy in between the two, over the history of the universe.
Third, we discovered the nearby universe looks more like young galaxies from the early history of the universe than it does the dinosaurs in the backyard.
The final thing is that around many galaxies, there are large gigantic zones of star formation that were not known before. We haven’t explained them yet, but it’s likely that there’s new galaxy-building material coming from the region between galaxies and creating new stars in the very outskirts of galaxies.
PS: Now that you’ve figured out how to get a NASA loan, do you think this will happen with other spacecraft?
CM: GALEX has the unique feature that the operations cost is very low, and the science impact of these ongoing extended operations continues to be very high. $100,000 is a chunk that can be swallowed by many organizations, and a month of observations gives you a huge amount of data. So we think it’s cheap in that respect. But I think other missions will be contemplating this as we go forward.
It’s a new kind of arrangement, so I would expect that it would open doors. it’s already piqued interest in a number of corners. We’re looking for private foundations which might be interested in being a part of this new paradigm space mission.
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