Earth Day: 10 Incredible Hubble Telescope Images Of Our Universe (PHOTOS)

My place in Hubble's story began after completing my Ph.D. work at Northwestern University and then going to Princeton to work as a young researcher. I could never have imagined that after being hired by NASA in 1978, I would become Hubble's chief scientist in 1979, a job I would hold for 20 years.

The Hubble story is a teachable moment in perseverance and unparalleled teamwork. Hubble launched aboard Space Shuttle Discovery in April 1990. Astronomers' dreams were finally fulfilled with a large, optically superb telescope orbiting above the Earth's distorting atmosphere to provide uniquely clear and deep views of the cosmos.

During Hubble's initial check out, scientists discovered it was near-sighted. The supposedly perfect primary mirror had been ground into the wrong shape. This imperfection was one-fiftieth the width of a human hair, but it prevented light from the outer regions of the mirror coming into focus at the same point as light from the inner regions. In science terminology, this is called a spherical aberration.

Instead of becoming a national treasure, Hubble was a national embarrassment. To me this compared to being on top of Mount Everest then tumbling down to Death Valley. While the mirror itself could not be fixed, a new camera and other instruments were developed with corrective optics to cancel out the aberration. In a sense, during a 1993 space shuttle mission, we gave Hubble glasses.

To keep Hubble healthy, regular servicing missions were needed to replace failed components, install new hardware and enhance imaging capabilities. Missions were conducted in 1997, 1999, and 2002. In essence, shuttle astronauts were Hubble's physicians and surgeons.

The final servicing mission launched aboard Space Shuttle Atlantis in May 2009. Astronauts conducted unprecedented repairs and replaced instruments using new, untried techniques. It was bittersweet closure for me to see our astronauts safely return from servicing Hubble one last time. Their success retrofitted Hubble with a full suite of scientific instruments, batteries, gyroscopes and other equipment, making the telescope more powerful than ever and equipped it to explore well into the next decade.

Hubble was the result of a herculean effort by thousands of dedicated individuals including scientists, managers, engineers, support staff, NASA center personnel, contractors, international partners and astronauts.

Hubble has enabled our minds and spirits to travel billions of miles and billion of light years to bring the universe close up and personal. A large part of Hubble's success and longevity is due to worldwide public support for the telescope. Hubble is an instantly recognized science icon and its positive impact on the world will continue for decades.

While the book "Hubble: A Journey Through Space and Time" represents a sampling of the telescopes' 20-year contributions, many of Hubble's greatest discoveries are yet to come.

The following images are featured in the new book by Edward J. Weiler, "Hubble: A Journey Through Space and Time," published by Abrams in collaboration with NASA.