Tricky Repair of Camera Goes Well for Astronauts
Published: May 16, 2009
So what was all the fuss about?
After two days of tense spacewalks drawn out by balky bolts and badly fitting equipment, the astronauts aboard the space shuttleAtlantis on Saturday breezed through the trickiest and most delicate job of their 11-day mission to the Hubble Space Telescope: fixing a camera that had not been designed to be repaired in space.
Working as calmly as if they were in shirt sleeves in the basement rather than wearing the equivalent of boxing gloves and sailing through space at five miles per second, John M. Grunsfeld and Andrew J. Feustel conducted “brain surgery” on the Hubble’s Advanced Camera for Surveys. They unscrewed screws not meant to be unscrewed and yanked circuit boards, finishing in less than three hours a job that had been allotted nearly five hours and two spacewalks.
Even the most optimistic members of the team had warned that repairing the camera was a long shot. Dr. Grunsfeld, already respected for his Hubble fix-it endeavors on two earlier missions, said before the flight that this would be a nail-biter.
When he began to remove screws almost an hour ahead of schedule, gasps and cheers broke out in the cabin of Atlantis.
“I don’t think real brain surgeons say ‘Yahoo’ every time they pull something out,” Dr. Grunsfeld said.
“Maybe they should,” replied Col. Michael T. Good of the Air Force, who was orchestrating events from inside Atlantis.
The day’s success raised the repair team’s confidence that it would succeed on Sunday, when similar surgery will be tried on another ailing instrument, the Space Telescope Imaging Spectrograph.
It was, as Scott D. Altman, the shuttle’s commander, said Saturday morning as the astronauts set out, “a great day for a spacewalk.”
Dr. Grunsfeld was on his second spacewalk of this mission and his seventh over all, every one in the name of the Hubble. Dr. Feustel was making his second spacewalk. On Thursday, the pair overcame a stuck bolt to replace the most ancient of the Hubble’s cameras, the wide-field camera No. 2, with a new version.
Dr. Grunsfeld and Dr. Feustel warmed up for the main event by installing on the Hubble a new spectrograph, the Cosmic Origins Spectrograph.
Spectrographs break down light into its constituent wavelengths, allowing astronomers to discern the composition, temperature and motions of celestial objects. The Hubble’s astronomers hope to use the instrument to trace tendrils of gas that stretch through the universe like a spider web, connecting galaxies.
The new spectrograph went into a slot occupied for the last 16 years by a box of corrective lenses known as the Corrective Optics Space Telescope Axial Replacement system. When it was installed in the space telescope in 1993, it provided special lenses that folded like a shower rod and took the blur out of the Hubble’s flawed vision. But all of the Hubble’s instruments now have their own correction optics, and Costar is headed for theSmithsonian Institution.
The advanced camera was a workhorse until its demise in 2007, with some of the Hubble’s most famous pictures to its credit, including the one in 2004 called Ultra Deep Field, which showed galaxies forming only 800 million years after the Big Bang.
Engineers were planning three hours’ worth of tests overnight to make sure the camera was repaired.
When it conked out in 2007, engineers said it was unlikely that the camera could be fixed. Not only was it not designed to be taken apart by astronauts wearing boxing gloves, and some parts of it were inaccessible, but the astronauts already had their hands full training to repair a spectrograph that had also not been designed to be tinkered with in space. That work will be the highlight of the spacewalk on Sunday.
http://www.nytimes.com/2009/05/17/science/space/17hubble.html?_r=1&ref=science
Exploration at NASA
As the space shuttle approaches retirement and the International Space Station nears completion, NASA is building the next fleet of vehicles to bring astronauts back to the moon, and possibly to Mars and beyond.


UFO No Longer Unidentified

Image above: High-resolution, digital scan of a full frame from the original Apollo 16 film showing the object in question (top center) and its position relative to the moon. Reflections in the window are also visible (left and right). Credit: NASA
Beginning their return from the moon to an April 27, 1972, splashdown, Astronauts John Young, Thomas Mattingly and Charles Duke captured about four seconds of video footage of an object that seemed to look a lot like Hollywood's version of a spacecraft from another world.

The thing was described as "a saucer-shaped object with a dome on top." The images were captured with a 16mm motion picture camera shooting at 12 frames per second from a command/service module window. The object appears momentarily near the moon. As the camera pans, it moves out of the field of view. It reappears as the camera pans back. It appeared in about 50 frames.
Some very bright people recently worked hard to analyze that footage. Their conclusion was that the object wasn't at all what some observers thought it seemed to be. There is no indication the Apollo 16 crew ever thought the film showed anything special.
A group headed by Gregory Byrne of Johnson Space Center's Image Science and Analysis Group completed a report on its investigation earlier this year. They used a video copy of the film initially, then did a high-resolution digital scan of the original film for detailed analysis.

They stabilized images to correct for camera movement, and then aligned multiple frames in a sequence. One thing that showed them was that the object appeared to move slightly with respect to the moon, because of parallax brought about by slight camera motions and the nearness of the object to the camera.
The investigators also combined several frames in a sequence, to give them higher resolution and greater contrast than individual frames. The combinations showed them more clearly a "linear feature" attached to one side of the object. They also looked at archived images from other Apollo missions.
Bottom line: "All of the evidence in this analysis is consistent with the conclusion that the object in the Apollo 16 film was the EVA [spacewalk] floodlight/boom. There is no evidence in the photographic record to suggest otherwise."

Image above: Enhanced Apollo 16 image (left) compared with features of the EVA floodlight/boom from the perspective of a Command/Service Module window (right). Credit: NASA