Key Concepts
Hubble Space Telescope, space telescope, mirror flaw, spherical aberration, servicing missions, Wide Field Planetary Camera, Corrective Optics Space Telescope Axial Replacement (COSTAR), Hubble Deep Field, Hubble Extreme Deep Field, NASA, Space Shuttle, public perception, scientific discovery, team collaboration, redemption.
Hubble's Genesis and Ambitious Goals
The Hubble Space Telescope, conceived as a machine to tour the universe from Earth, represents a pinnacle of human ambition and scientific advancement. Named after Edwin Hubble, the orbiting observatory is the largest of its kind, exceeding 13 meters in length and weighing over 12 tons. Its 2.4-meter mirror, positioned above Earth's atmosphere, promised unprecedented clarity and detail from the farthest reaches of space. The goal was to see 100 times more detail and fainter objects than ever before. Lyman Spitzer proposed the idea in the 1940s, and NASA began planning in the 1960s.
Technical Challenges and Engineering Marvels
Placing a telescope in space presented immense technical challenges. Maintaining stability was paramount; the "jitter spec" required pointing accuracy of 0.007 arc seconds. Ed explains this accuracy by comparing it to pointing a laser from the Washington Monument to a dime on the Empire State Building in New York City and keeping it pointed at Roosevelt's head. Perkin Elmer, contracted for much of the technical work, initially deemed the specifications impossible. The mirrors needed unprecedented smoothness, accurate to millionths of an inch. The analogy used is grinding the Earth's surface smooth, where the largest mountain would be only 4 inches high.
Development Setbacks and Communication Breakdown
The mirror polishing process, controlled by computers, was slow and meticulous. Perkin Elmer underestimated the time required, leading to funding cuts and schedule pressure. NASA rejected final testing against the engineer's wishes. Lou recalls getting calls in the middle of the night to check on the progress. Charlie Pellerin, responsible for Hubble's delivery at NASA, was told to "beat up the contractors." A breakdown in communication occurred, with Perkin Elmer withholding information they thought would upset NASA.
The Challenger Disaster and Launch of Hubble
In January 1986, the Space Shuttle Challenger exploded, killing the crew and halting shuttle launches. This disaster cast uncertainty over Hubble's future. Despite the setback, the team persevered, and after almost three years, the Space Shuttle Discovery launched with Hubble in its payload bay. The launch was described as having "your future personally riding on this thing."
Initial Deployment Issues
During deployment, one of Hubble's solar arrays became stuck. Story Musgrave, capsule communicator at Mission Control, described the situation as "exceedingly difficult." With dwindling battery power, mission control had to act fast. A sensor indicated excessive tension in the panel, so NASA decided to disable the tension monitoring system, a risky gamble. The gamble paid off, and the solar array deployed.
Discovery of the Mirror Flaw and Public Backlash
After Hubble was in orbit, the first images revealed a devastating truth: the mirror had a serious defect called spherical aberration. Light rays hitting the edges of the mirror focused differently than those hitting the center, resulting in blurry images. John Trauger described the images as having a sharp core but also an unexpected "skirt." The telescope was rendered almost useless. The news was announced to the world on June 27, 1990. Bud lamented that they didn't get a chance to make the final measurements. Charlie Pellerin took responsibility for the "leadership failure." Hubble became a symbol of failure, and Senator Barbara Mikulski, who secured NASA's funding, expressed her outrage.
Finding a Solution and Planning the Rescue Mission
Astronomer Chris Burrows played a critical role in diagnosing the mirror flaw. The mirror was a perfect curve, but off by a millionth of an inch at the edge. The team brainstormed numerous solutions, including putting a corrector over the whole front of the telescope or having astronauts coat the primary mirror. The chosen solution involved installing a new Wide Field Planetary Camera (WFPC2) with corrective optics and a Corrective Optics Space Telescope Axial Replacement (COSTAR) to correct the images for the other instruments. The WFPC2 had four small mirrors with the opposite prescription curve to cancel out the aberration. John described COSTAR as a "sophisticated box about the size of a phone booth" that would mechanically deploy a periscope-like device.
The First Servicing Mission and Redemption
The rescue mission became more than just fixing a telescope; it was about the future of NASA and the Space Shuttle program. Story Musgrave was chosen as the payload commander. The Space Shuttle Endeavour launched on December 2, 1993, carrying the new camera and COSTAR. The astronauts faced challenges during the spacewalks, including the delicate pick-off mirror in the WFPC2. After the repairs, the first images from the fixed Hubble were a resounding success. Jeff described the moment the first sharp image appeared on the screen as "nailed it." Champagne corks popped, and NASA held a press conference to announce the good news.
Scientific Breakthroughs and Iconic Images
With Hubble fixed, astronomers queued up for observing time. One of Hubble's first big successes was capturing the impact of Comet Shoemaker-Levy 9 on Jupiter. Heidi described Hubble having a "ringside seat" and the images as "spectacular." Jeff Hester captured the iconic "Pillars of Creation" image of the Eagle Nebula. Ed Weiler described the image as having "colorful pillars, clearly a gaseous nebula." The image was published on front pages worldwide and touched people in a profound way. Hubble continued to produce stunning images of galaxies, exploding stars, and nebulae. Stephen noted that Hubble's first year transformed our view of the Cosmos.
The Hubble Deep Field and Subsequent Servicing Missions
Hubble captured the Hubble Deep Field image by pointing at what seemed like an empty patch of sky for ten consecutive days. The image revealed thousands of previously unseen galaxies. Over the next two decades, three more shuttle missions upgraded Hubble with new equipment and cameras. John Grunsfeld participated in multiple servicing missions.
The Columbia Disaster and a Second Chance
In 2003, the Space Shuttle Columbia disintegrated upon re-entry, leading NASA to cancel the final servicing mission to Hubble. John felt stunned, as the mission was crucial to extending Hubble's life. However, in 2005, NASA's new administrator, Mike Griffin, announced that a servicing mission would be added.
The Final Servicing Mission and Hubble's Legacy
In 2009, John Grunsfeld and his crew embarked on the final servicing mission to Hubble. They installed a new camera and performed other upgrades. During the spacewalks, they encountered a stuck bolt on the old camera. Drew Feustel managed to break the bolt loose, saving the mission. The crew released Hubble one last time.
The Hubble Extreme Deep Field and Enduring Impact
With the new camera installed, Hubble captured the Hubble Extreme Deep Field image, revealing another 5000 previously unseen galaxies, some over 13 billion light-years away. Charlie Pellerin described the image as "astounding." Stephen noted that the image is proof of the vastness of the cosmos. Bud reflected on the fact that the light from these galaxies left billions of years ago and is now in our possession. After more than 25 years, Hubble remains the most beloved scientific instrument in history. Jeff concluded that Hubble's images will be remembered and revered for a long time to come. Ed described Hubble as the "great American comeback story."
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