Do you remember what you were doing 18 years ago today? I was sitting in the press auditorium at NASA's Goddard Space Flight Center in Greenbelt, Maryland, watching a large video display showing astronauts aboard the Space Shuttle Discovery working to deploy the Hubble Space Telescope. With more than 20 years of effort and more than $1.5 billion invested in the project, the stakes were high indeed.
Discovery's launch the previous day had gone off without a hitch, but this day things weren't going so well. Crew members Bruce McCandless and Kathryn Sullivan were in the shuttle's airlock, wearing spacesuits and preparing to head outside to give Hubble a helping hand. The telescope's huge solar-cell wings weren't unfurling properly — they were stuck partway out and threatening to tear.
Flight controllers were eventually able to remotely adjust the tension in the deployment mechanism and slowly inch the solar arrays to their full extension, so McCandless and Sullivan avoided an emergency spacewalk. Soon astronomer-astronaut Steven Hawley, at the controls of the shuttle's robotic arm, released his grip on Hubble and sent the telescope on its way as astronomers the world over cheered it on.
Barely two months later, astronomers were plunged into the depths of despair. Early images revealed that Hubble's vision was blurred by spherical aberration, an optical defect that's common in cheap telescopes but inexcusible in one costing billions. Rather than fulfilling astronomers' dreams, Hubble was a nightmare — the butt of jokes on late-night television and a terrible embarrassment for anyone with any connection to astronomy.
Yet, as everyone knows, NASA and its partner, the European Space Agency, refused to give up on Hubble. The agencies' best scientists and engineers came up with a plan to counteract the flawed optics, and in December 1993 astronauts aboard the shuttle Endeavour made Hubble right. Over the next 15 years, by enabling landmark discoveries from our solar system to the edge of the visible universe, the telescope has become widely acknowledged as perhaps the most successful scientific instrument of all time.
On this 18th anniversary of Hubble's deployment, NASA is preparing for the last of its scheduled service calls to the telescope. On shuttle mission STS 125, the only remaining flight not going to the International Space Station, seven astronauts will rendezvous with Hubble to install new scientific instruments, replace worn-out mechanical and electrical parts, add new insulation blankets, and raise the spacecraft's orbit. Launch is officially scheduled for August 28th, but word within the project is that it'll slip at least a little, perhaps to mid-September.
If all goes well during this year's servicing mission, Hubble should be able to remain scientifically productive for another 5 years or more. In fact, because of the improved sensitivity of its new detectors, it should be able to "push the envelope" of cosmic discovery even more aggressively than it has over the last 15 years.
So, happy birthday, Hubble — and many more!
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