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Planetary News: Hubble Space Telescope (2009)A Rejuvenated Hubble Space Telescope Wows Scientists and Astronautsby Emily LakdawallaSeptember 9, 2009
Today NASA unveiled a collection of spectacular images captured by the Hubble Space Telescope, which was given a new lease on life during Hubble Servicing Mission 4 in May. "Prior to this mission, we were down to three operating channels" on Hubble, senior project scientist Dave Leckrone said at a press briefing held at NASA headquarters this morning. "Today we have thirteen, on six fully operating instruments. I am not able to report any failure or problem on the spacecraft itself." This statement was followed by applause from the audience of reporters, NASA officials, and the seven astronauts of STS-125, the servicing mission. The unveiling was opened with statements from new NASA administrator Charles Bolden and from senator Barbara Mikulski of Maryland. Mikulski asserted that Hubble is a unique facility not just for science but also for America's image abroad. "Very few people realize that what we have done with Hubble is one of the greatest forms of public diplomacy that the United States has. We thank our international partners for the wonderful things they do. [But] when it comes to space, we are the indispensable nation." The most visually stunning images came from the brand-new camera, the Wide Field Camera 3 (WFC3), which replaced the workhorse Wide Field Camera 2 and most of the functionality of the NICMOS infrared imager. The new WFC3 will be used in half of all the Hubble science observations planned for the next year, said Bob O'Connell, chair of the Hubble Space Telescope science oversight committee. O'Connell presented four photos from WFC3. Among them was this visually arresting one of the Butterfly nebula, a planetary nebula located within our galaxy, about 3,800 light years away in the constellation Scorpius. The nebula is a visual signal of the death throes of an aging star, but the butterfly structure itself is only thousands of years old.
Also among the stunning releases from the new WFC3 is this one of a "pillar of creation" in the Carina nebula. This pair of images showcases WFC3's ability to capture wide-field images in infrared wavelengths, something that Hubble has not been able to do before. With its infrared detector, WFC3 largely replaces the older NICMOS instrument, replacing the low- and medium-resolution capability of NICMOS with a much wider field of view and allowing direct comparisons between the visible- and infrared-wavelength appearances of large astronomical objects.
Other amazing photos came from two instruments that were brought back from death by the hardworking astronauts of Hubble Servicing Mission 4, the Advanced Camera for Surveys (ACS) and the Space Telescope Imaging Spectrograph (STIS). As Leckrone explained, "A unique aspect to mission was attempt to repair two instruments: STIS, which failed in 2004, and ACS, which failed in 2007, in both cases because of electronic short circuits. A bold effort was undertaken to attempt to repair both instruments."
The effort was "bold" because neither STIS nor ACS was ever intended to be repaired in orbit. To repair STIS, astronauts had to remove 111 separate screws to allow them to access the failed power converter. At one point, it appeared that a handrail would block astronauts' access to STIS; mission specialist Mike Good had to use brute force to break a bolt to remove the handrail to allow them to continue. The repair of ACS was less dramatic, requiring the installation of a new power supply on the outside of the instrument; its wide-field channel (but not its high-resolution channel) was brought back online. Leckrone said, "We never dared dream of the possibility that both repairs might work. But both are working splendidly." The repair of STIS allows scientists to continue long-duration studies of changing phenomena in the galaxy, Leckrone said, pointing in particular to STIS observations of the volatile behavior of Eta Carinae, a double star that is surrounded by brilliant lobes of gas. "We've been monitoring this since 1997, and then we had to stop in 2004 and we haven't been able to continue the story. Thanks to [the astronauts of Hubble Servicing Mission 4] we're back up and running and now the story continues. Someday in the future, this is going to become a spectacular fireworks show."
ACS was represented in the press briefing by a new image of galaxy cluster Abell 370, located 5 billion light years away. This cluster of galaxies is unusual not for the properties of the individual galaxies within it, but instead for how the mass of the galaxy cluster -- and all the dark matter associated with it -- acts as a gravitational lens to magnify images of galaxies located twice as far away. "This is nature's telescope, taking the power of Hubble and enhancing it with gravitational lensing," Leckrone said.
All of the images planned for public release from Hubble's commisioning phase were of targets well outside our solar system. But nature served up a surprise to astronomers during Hubble's shakedown: the discovery by amateur astronomer Anthony Wesley of a freshly formed impact scar near Jupiter's south pole on July 23. Astronomer and Planetary Society board member Heidi Hammel spoke about the discovery: "We got a report in the middle of the night that something had hit Jupiter. Once we had convinced ourselves that that was correct, all telescopes in the world turned to Jupiter. The question that I grappled with was, well, what about Hubble? Fifteen years ago, exactly, when a shattered comet, Shoemaker-Levy 9, had crashed into Jupiter, Hubble was at the forefront of the observations, and I had been at the helm of the Hubble team. So, could we do it again?" Hammel explained that the Hubble team was involved in "Servicing Mission Orbital Verification (SMOV)," a long-planned, carefully orchestrated process of calibration and testing. "Interrupting orbital verification? Not a good idea. Words like, 'impossible' and 'inconceivable' were bandied about. So I was asked: what was it that Hubble, and only Hubble, can do? And I responded: high-resolution visible imaging and ultraviolet imaging, only Hubble can do that. So we got approval for the time." In fact, they got approval for multiple observations; the last image hit the ground yesterday, and Hammel said she had not seen it yet. They released a small version of the Hubble shot of the impact site in July; today, they unveiled the full-globe image. Hammel said, "This is our highest resolution image of Jupiter since 2007, when the New Horizons mission flew over the cloud tops of Jupiter. And you can see the impact site, but you can also see fantastic structure and detail across the rest of the disk. This illustrates a superb aspect of the revitalized Hubble, and that's its wide-field imaging capability. This is something that all of us are going to be taking advantage of -- the ability to take very large pictures."
What's next for the newly refurbished Hubble? The spacecraft should be good for another five years of operations. Currently Hubble is in "Cycle 17" of observations, which is "a yearlong, pre-selected peer-reviewed observing program," Leckrone said. He mentioned two specific plans for the next year of Hubble operations: "We're all interested in Pluto, we know there is a whole population of Pluto-like objects in the Kuiper belt, so we're going to be doing a large survey to understand the outer solar system. And we will continue looking at the atmospheres of planets around other stars." Science is of course at the forefront in the process by which Hubble observations are planned. But no one on today's panel was immune to the aesthetic quality of Hubble photographs. Hammel related her reaction to seeing the first images of Jupiter from the new camera: "all we could say was 'wow.' You don't lose the wonder; the beauty is there to be appreciated in each new image from Hubble. You don't get jaded. You keep being enthralled with every new image." The Servicing Mission astronauts agreed; speaking on a panel after the scientists, they all said that their first response to new images from Hubble was "wow."
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