“If there were ever two missions that were completely opposite in terms of the public attention that was given to them,” astronaut Loren Shriver once said, “it would be my first and second missions.” It was no understatement. His first shuttle flight had been totally cloaked in military secrecy, whereas his second launched NASA’s scientific showpiece: the $1.5 billion Hubble Space Telescope. Today, 24 April 2015, marks 25 years since the telescope was ferried into orbit aboard Shuttle Discovery on STS-31, beginning a journey and an enduring reputation as one of the most successful astronomical observatories ever launches. Over the past quarter-century, Hubble has peered deeper into the Universe than ever before, acquired images of distant galaxies, created breakthroughs in physics and cosmology, witnessed a comet hitting Jupiter, tracked winds on Uranus and Neptune, and—until the middle of May 2015—will continue to hold the record for having taken the most detailed “map” of far-off Pluto. “There was no doubt in my mind,” said Charlie Bolden, STS-31’s pilot and today’s Administrator of NASA, “from the moment I was assigned to the Hubble deployment mission about the historical significance of what we were doing. That was one monster flight!” Yet a mix of misfortune, poor manufacturing, and inadequate program oversight almost turned Hubble from a white knight into a white elephant.
With the advent of the Space Age, it came as little surprise when plans for an orbiting telescope materialized as an important next step in astronomy. Since the Second World War, physicist Lyman Spitzer of Yale University argued that such a telescope would offer enormous advantages over ground telescopes, unimpaired by the distorting effect of Earth’s atmosphere and empowered with the ability to detect high-energy emissions, including X-rays, from distant celestial sources. In 1975 NASA tried to sell the telescope idea to Congress. It was rejected by the House Appropriations Subcommittee, which reasoned that it was too ambitious, too expensive (at $400 million), and did not have the necessary support from the National Academy of Sciences. Co-operation with the newly-formed European Space Agency (ESA) changed all that. The telescope would carry inexpensive solar panels, and its mirror was reduced in size from 10 feet (3 meters) to 8 feet (2.4 meters), effectively halving its cost.
By 1977 Congress had agreed to fund what was then named the “Large Space Telescope.” Prime candidates to build the mirror were Perkin-Elmer, with a bid of $64.2 million, and Eastman Kodak, teamed with the defense contractor Itek, which quoted almost $99.8 million. Despite being more expensive, Kodak-Itek offered two independent tests of the grinding and polishing quality of the finished optics. This “double-checking” provision was something Perkin-Elmer did not offer … and it would not go unnoticed when investigators dug into the causes of the telescope’s embarrassing problems, more than a decade later.
Perkin-Elmer received approval from NASA in 1979. Lockheed would build the spacecraft to house the mirror, and the Europeans would construct the solar panels. A Space Telescope Science Institute (STScI) was founded at Johns Hopkins University in Baltimore, Md., to handle the data, and the telescope was scheduled for a shuttle launch in 1985. By this time, it had been named in honor of Edwin P. Hubble, the American astronomer who not only conducted extensive research into the structure of stars and galaxies, but whose work also led to the surprising discovery that the Universe is expanding.
Optically, Hubble was a Cassegrain reflecting telescope and its twin hyperbolic mirrors were sold on the basis of their good imaging performance … but their shapes made them difficult to fabricate and test. Perkin-Elmer used special polishing machines to grind them, and, in case of problems, NASA directed them to subcontract to Kodak to build a backup mirror using traditional polishing techniques. (The Kodak mirror today sits in the Smithsonian.) In the meantime, Perkin-Elmer’s mirror was completed in 1981, washed in hot, deionized water, and coated with aluminum and a protective layer of magnesium fluoride. NASA, though, remained sceptical that the company was competent enough to fabricate the mirror, and delays quickly pushed Hubble’s launch back from April 1985 to the late summer of 1986. By this time the total project had soared to a little more than $1 billion.
Still, Hubble promised to whet every astronomer’s appetite. Five instruments—a wide-field planetary camera, a high-resolution spectrograph, a high-speed photometer, a faint object camera, and a faint object spectrograph—would provide the telescope with the capability to explore not only the visible region of the electromagnetic spectrum, but also the ultraviolet. Physically, the craft was as monumental in size as it was in performance: it ran to more than 43 feet (13 meters) in length and weighed nearly 24,250 pounds (11,000 kg), virtually filling the cavernous payload bay. Plans to regularly service it in orbit meant that it was dotted with EVA-friendly hand holds, and it would be deployed by means of the shuttle’s Canadian-built Remote Manipulator System (RMS) mechanical arm. That arm would be under the direction of astronaut Steve Hawley. Nicknamed “Attack Astronomer,” he had worked on Hubble ever since September 1985, when he was assigned as a crew member on Mission 61J, the flight to launch the telescope.
In his NASA oral history, Hawley quipped that he was chosen for the role because he was such a good RMS operator, but he was convinced that the need for an astronomer on this most astronomical of missions was crucial, “for the simple reason that we want to make sure … that the needs and requirements of the customer are understood and dealt with appropriately.” Of course, Hawley would not actually be using Hubble, nor would there be any real astronomy for him to perform, but he believed that it helped the scientists by having someone aboard who knew what they wanted to accomplish, knew the constraints, and, in a nutshell, cared about it.
By the time Challenger was lost, in January 1986, Hubble had been further delayed from August to October. In addition to Perkin-Elmer’s problems, Lockheed had also thrown itself over-budget by upwards of 30 percent and was three months behind schedule. This brought the project dangerously close to breaking a Congressional-imposed budget “ceiling.” In perhaps the most cruel of ironies, the agony of Challenger actually worked in Hubble’s favor, for it provided the breathing space to get everything ready. In June 1986, the telescope passed a major thermal vacuum test with flying colors and the enforced delay time was used to add more powerful solar arrays, improve redundancy of on-board systems, and fit better connectors. Nickel-cadmium batteries were prone to failure and were replaced by nickel-hydrogen ones, and by early 1990 the Hubble team was electrified by the realization that their observatory would herald a new era of astronomy.
The international participation added a unique, and sometimes humorous, new angle. Astronauts Kathy Sullivan and Bruce McCandless closely monitored the development of Hubble’s solar arrays, which were being built by British Aerospace in Bristol, England. During one trip to England to work on the arrays, the pair arrived at London’s Heathrow Airport, after an exhausting flight, and drove through the night to Bristol for several tests. Sullivan expected to immediately don clean-room garb and begin work, but the British Aerospace team had other ideas.
“We found ourselves in these rather more formal Welcome the flight crew events,” she told the NASA oral historian, “which I hadn’t expected.” A brief walkthrough of the solar array, suspended in a rig above a water table, followed, after which the astronauts expected to dig into the tools and procedures they might someday need in the event of a contingency EVA on the telescope. However, it was lunch time and the astronauts were instead ushered into a management dining room, where—to their horror—they beheld engineers and technicians drinking pints of ale or glasses of wine. Who in their right minds, they wondered, would possibly consume alcohol, minutes before handling delicate flight hardware?
Answer: The English, naturally.
For her part, Sullivan enjoyed Bristol, although when she later spoke to fellow astronaut Kathy Thornton—who flew the first Hubble repair mission in December 1993—it became clear that in addition to visiting British Aerospace, her crew also got an extended tour of English historic landmarks, including Stonehenge. “Maybe that’s what you get if you’ve successfully fixed their solar array,” Sullivan said, with a hint of humor. “We didn’t get that. We just went over there, worked and came home.” Aside from the humor of the episode, British Aerospace’s treatment of the crew was entirely understandable; for in addition to the technical role, Hubble had major European involvement and the arrival of the shuttle astronauts who would deploy it was accorded the right level of significance.
Nor was that significance lost on the part of NASA Administrator Jim Beggs. He had encouraged his subordinates to regard Hubble on a par with the shuttle itself and even went so far as to label it “the eighth wonder of the world.” With this in mind, it is unsurprising that John Young, the agency’s chief astronaut, was selected to command Mission 61J to deploy the telescope. He had barely begun training with his crew when Challenger was lost, and in April 1987—for reasons explored elsewhere—he was removed from flight status. When the “new” Hubble deployment crew of STS-31 was named in March 1988, with launch set for June of the following year, Young was replaced by Loren Shriver. As the shuttle returned to normal operations after Challenger, it became clear that Hubble was not an “infrastructure-critical” mission and would have to take its place in the line behind the Tracking and Data Relay Satellites (TDRS), Department of Defense assignments and planetary missions tied to specific, and largely immovable, launch windows.
Eventually, the crew found themselves targeted for the March-April 1990 timeframe, and that posed its own challenges. “The year 1990 was close to a solar maximum year,” said Kathy Sullivan, “so the envelope of the atmosphere is physically larger.” This had implications for the precise altitude of Hubble’s orbit. As the launch slipped from 1986, in a time of reduced solar activity, to 1990, closer to the maximum, the Hubble deployment altitude was raised to a little more than 380 miles (610 km). This high altitude meant that a long-duration Orbital Maneuvering System (OMS) firing of more than five minutes was needed for orbital insertion, and the effect upon the shuttle’s performance was that no less than 50 percent of the available OMS propellant for the whole five-day mission would be consumed by the time Discovery achieved orbit!
On top of this was the need for sufficient margin to re-rendezvous with Hubble, if necessary, after deployment, and perhaps repair it, then re-release it, perform another separation maneuver, and still have enough propellant stores for the de-orbit “burn” and return to Earth. (The de-orbit from Hubble’s altitude was expected to require an OMS burn of almost five minutes, some 60 percent longer than other shuttle missions.)
In the weeks before launch, it was evident that STS-31 would have much lower reserves of propellant at the start of its mission than had been typically on other flights. As a result, a significant amount of training time was devoted to how the crew responded to propellant leak alarms; on an “ordinary” mission, the first prudent step would have been to verify if the alert was a false one, but on STS-31 the assumption had to be taken that it was a leak and preparations to either substantially lower their altitude or de-orbit had to be made quickly. All of those steps had to be performed in parallel.
Yet the launch was eagerly anticipated by the astronomical community. “After 45 years of dreaming,” wrote John Noble Wilford in the New York Times on 9 April 1990, “and almost 20 years of planning, development and delays, the Hubble is ready to be taken into orbit.” No one could possibly have foreseen the tortured childhood that this icon of astronomy would have to endure in the months and years to come, and, by the end of 1990, as public and politicians alike came to regard Hubble as a laughing-stock and bait for late-night TV jest, few could have imagined that the telescope would go on to become NASA’s salvation. In its own way, the success story that Hubble became helped to assure NASA the political support it needed to build today’s International Space Station (ISS).
The second part of this article will appear tomorrow.
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The fly-through animation on the Hubble 25th anniversary page is pretty cool. It occurred to me that the speed of the virtual camera was way off-the-scale. A ‘speedometer’, warp-factor, order of magnitude on the graphic would be … fascinating. Congrats to the Hubble team and NASA.
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