Each of theseven NASA astronauts set to launch to the Hubble Space Telescope next week hasa favorite view of the universe courtesy of the long-lived observatory, addingsome extra motivation to their vital orbital repair mission.
Veterancommander Scott Altman and his crew are poised to rocket toward Hubble on May11 aboard the space shuttle Atlantis to overhaul the iconic telescope for thefifth and final time. If all goes well, the tricky 11-day mission ? whichincludes five back-to-back spacewalks and some unprecedented repairs ? willextend Hubble?s cosmic scanof the universe through at least 2014.
?I rememberwhen I was a kid going outside and looking up at the stars and going, ?Wow, Iwonder what?s out there,?? Altman said in NASA interview. ?Hubble is a toolthat can take you out there to those distant galaxies, those pictures that comeback ? I think it connects with people on a very visceral level.?
Since itslaunch in 1990, Hubble has collected more than 880,000 observations and takenover 570,000 images of about 29,000 celestial objects in the universe. Altmanand his crew took some time recently to review their all-time favorite imagesfrom Hubble?s ongoing mission to peer into the cosmos:
Of Miceand astronauts
Of the mountainof images beamed to Earth by Hubble, Altman holds the telescope?sview of two colliding juggernauts - nicknamed the ?Mice galaxies? - as hispersonal favorite.
Taken in2002 just after Altman led NASA?s most recent Hubble servicing mission STS-109, theimage shows the two galaxies - each sporting a long tail (hence the nickname) -as they close in on one another some 300 million light-years from Earth in theconstellation Coma Berenices, or Berenice's Hair.
?Justthinking about that being out there amazes me,? Altman said, adding that behindthe two colliding galaxies are some 1,500 other distant galaxies, each with abillion or so stars. ?You start thinking, this is a soda straw slice of thenight sky with a number that?s huger than I can really comprehend of othergalaxies with billions of stars in each one of them. And I?m saying, wow, thisis a big place we live in.?
Hubble usedits then-new Advanced Camera for Surveys, which is now in need of repair, totake the snapshot.
Gaze ofthe Cat?s Eye
Hubble?sstellar views of the Cat?s Eye nebula, a distant planetary nebula first spottedby the telescope in 1994, take center stage for Atlantis pilot Gregory C.Johnson.
?Obviouslywe launched Hubble in 1990, we fixed its optics in ?93 and in 1994 they foundthis nebula outside of our galaxy,? Johnson said. ?The picture is justastounding.?
The Cat?sEye nebula is also known as NGC 6543 and sits about 3,000 light-years fromEarth in the constellation Draco. The nebula?s concentric rings are the resultof eruptions of mass ejected away from its central star every 1,500 years orso.
For U.S.Air Force Col. Michael Good, part of the four-man spacewalking team that willperform the upcoming Hubble repairs, the pinnacle of the telescope?s cosmicvision used to be the Ultra Deep Field.
Compiledover the course of 400 orbits between September 2003 and January 2004, theUltra Deep Field is a portrait of some 10,000 galaxies in a patch of sky in theconstellation Fornax. The image revealed galaxies that emerged just 700 millionyears after the theoretical Big Bang.
?It?sprobably not the most beautiful image out there,? said Good, who added they itwas what the image represented that struck him. ?To literally be looking at thefirst light of the universe, I think that?s a pretty interesting and prettyamazing capability.?
But aslaunch day nears, Good said recently that he has a new top pick for Hubble?sfinest.
?My answernow is going to be the next image. The next image we get from the telescopeafter we leave,? Good told reporters in a recent briefing. ?That?ll be myfavorite.?
Shuttlerobotic arm expert Megan McArthur, who will use Atlantis? robotic appendage topluck Hubble from its orbit so it can be fixed, has said she?s also fond of thetelescope?s views of the Ultra Deep Field and the Cat?s Eye nebula.
But thesheer wealth of data and imagery collected by the telescope?s camera eye overthe last 19 years is muchricher than a single snapshot, she added.
?I thinkthat, in general, almost every picture I see is my favorite,? she toldreporters recently. ?They?re all just awe-inspiring to me. I really can?t pickjust a single one.?
Hubble?sspacewalk repair chief John Grunsfeld, a self-labeled ?Hubble hugger making hisfifth spaceflight and third trip to the telescope, said the image closest tohis heart is a 2002 snapshot of a pair of galaxies caught in the act ofcolliding.
The image depictsthe Tadpole galaxy, known as UGC 10214, which Hubble spotted after it had beenwalloped by a smaller galaxy that gave it a trademark tail that stretches280,000 light-years away from the collision. The image was one of the firstreleased after Hubble?s 2002 service call, which Grunsfeld also flew on.
?That wasone of the first released images after we put the Advanced Camera for Surveysin on our last mission,? said Grunsfeld, who will perform three of the fivespacewalks to upgrade Hubble this month. ?I?m looking forward to the earlyrelease images from this mission.?
The coneof success
Veteran Hubblespacewalker and repairman Michael Massimino has tapped the Cone Nebula as hischoice for the space telescope?s greatest hit. Like the Mice galaxies and theTadpole galaxy, it was among the first images following Hubble?s STS-109servicing flight in 2002, which Massimino participated in with Grunsfeld andAltman.
The ConeNebula, or NGC 2264, sits about 2,500 light-years from Earth in theconstellation Monoceros and earned its nickname from its conical appearance inground-based images. The nebula is vast, stretching across 7 light-years inlength, but the Hubble image released in 2002 revealedonly its upper 2.5 light-years.
?I liked itbecause it was beautiful, but also because we put the camera in correctly,?Massimino said in a recent briefing. ?It all worked and we didn?t breakanything, and that was our final validation that the job we did on STS-109 wasa good one.?
Untilrecently, first-time spaceflyer Andrew Feustel said that visions of the Eskimoand Ant nebulae were his favorite views from Hubble. But that changed lastmonth when NASA unveiled the Cosmic Fountain, a new image from theobservatory?s Wide Field Camera 2 to celebrate the telescope?s 19th birthday.
The imagerevealed three interacting galaxies that resulted in a fountain-like objectdubbed Arp 194. It sits about 600 million light-years from Earth in theconstellation Cepheus.
Feustelsaid he was so impressed by the image, which resembles a cosmic question markor fountain, he immediately set it as the desktop wallpaper for his computer.
?It?spretty spectacular and I think it?s Hubble?s way of asking us what?s next,?Feustel said. ?I?m curious to see what?s next as well.?
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