Just about everyone has heard of NASA’s Hubble Space Telescope — not too surprising considering that it has been with us for the past 35 years. For the majority of people alive today, the HST has been operating in Earth’s orbit for most, if not all, of their lives.
My own memories of its launch and initial problems are especially clear because I was involved in astronomy and space science education, and already writing this monthly Skywatch column. In the decades since, I’ve watched the HST transform our collective consciousness and consider its launch a significant event in the history of our species.
Until the launch of the James Webb Space Telescope in December 2021, the HST was the world’s largest space-based telescope — a giant telephoto camera pointing away from Earth, and out into the great beyond.
The staggering and unprecedented beauty of its pictures, and other gathered data have transformed the way most humans envision our place in this immense and unexplored universe we inhabit.
On April 24, 1990, hopes were high as the Space Shuttle Discovery blasted off from Florida’s Kennedy Space Center. Tucked away inside its cargo bay, a shiny bus-sized telescope was all checked out and ready for its coming mission. That was the plan anyway.
To deliver the Hubble Space Telescope to its 345 mile high orbit, Discovery had to fly farther out into space than any previous shuttle. With minimal flight issues, the Shuttle successfully deployed HST to its intended orbit, where it remains to this day.
That was an important step in realizing a radical idea initially outlined in 1946 by astronomer Lyman Spitzer. Spitzer had argued that from outside Earth’s atmosphere (which blurs images and makes stars twinkle), a telescope’s resolution would be limited only by its optics, meaning that pictures could be as clear as the cameras were theoretically capable of. He also noted that a telescope in space could see in infrared and ultraviolet light that Earth’s air blocks from ground-based observatories.
Hubble Space Telescope however, was named for the American astronomer Edwin Hubble, who in 1929 showed that galaxies farther from us seem to be moving away more rapidly than those nearer. The evidence strongly suggested that we live in an expanding universe. Hubble also helped establish that many of the objects classified as “nebulae” were actually entire, previously unknown galaxies outside of our own Milky Way galaxy.
The Hubble Space Telescope is one of the greatest discovery machines of all time, pushing the limits of our knowledge and perception, and inspiring awe. The Hubble’s public face has been its jaw-dropping pictures of a variety objects and features throughout the cosmos, while a steady stream of tens of thousands of peer-reviewed papers have been published in scientific journals. HST data revolutionized our view of the universe.
At least some of this was anticipated. A few years before its launch, I attended a presentation by the Space Telescope Science Institute where high-resolution pictures of Jupiter and Saturn from the Voyager fly-bys were shown to illustrate the amazing performance designers expected from the orbiting observatory. That seemed almost unreal to me and others there, but we all knew we would soon find out.
Or so we thought. Soon after its successful launch and in-orbit tests began, signs emerged that there was trouble with Hubble. Few space enthusiasts will ever forget those first ridiculously blurry images. This was bad.
I remember feeling sad as I watched David Letterman joke about the debacle. I cringed, even as I chuckled as he told viewers how to make their “very own Hubble Space Telescope” by covering one end of a cardboard tube with toilet paper. Just hold that up to your eye and look through it, he said. It was appropriately brutal humor.
Soon after, an investigation determined that the 7.9 foot diameter primary mirror — the heart of the HST — was perfectly configured, but to the wrong specifications. The slightest imperfections in any telescope’s primary mirror, which gathers and focuses light, negatively affect image quality.
As awful and unexpected as the finding was, it came with some great news: the spherical aberration of the mirror could be fixed with corrective optics. In a sense, all the HST needed was prescription glasses. Fortunately, the Hubble Telescope had been designed to operate within reach of the Space Shuttle for future servicing, so the corrective optics were installed in 1993 during the first and most important of five repair missions. It didn’t take long for the new crisply focused Hubble images to become worldwide sensations.
The Pillars of Creation. The left image was taken by the Hubble Telescope using visible light in 2014. The right image shows the James Webb Space Telescope’s near-infrared view. (Courtesy of NASA)
In 1995, a picture dubbed “Pillars of Creation” was released. Getting lost in this image was a revelation, and I felt privileged by the opportunity. At once, the astonishing complexity visible in that cloud of gas and dust surprised astronomers and the public. The scale and depth it conveyed made it a cultural icon. The early Internet surely benefitted from the widespread sharing of this picture, which was also featured in magazines and printed on T-shirts. It riveted the public imagination.
A total of five Space Shuttle service missions were flown by brave astronauts, each leaving the telescope in better shape than before. Technology was rapidly advancing, so the original old-style tape recorder was replaced in 1997 with a solid state recorder. In 1999 a new computer gave HST six times the storage and 20 times the speed. Subsequent missions replaced solar arrays, providing 30 percent more power, and so on.
Then came the Space Shuttle Columbia disaster in 2003. NASA Administrator Sean O’Keefe had little choice but to cancel a final servicing mission to the Hubble. A few argued that it would be worth the risk since the HST was expected to fail in short order without it.
In 2004, NASA released an image revealing 10,000 galaxies in an “empty” patch of sky the size of a grain of sand held at arm’s length. The Hubble Ultra-Deep Field, as it is known, was assembled using data collected in the previous year. This was our deepest glimpse into the distant universe ever. With its profound impact on those who took a close enough look, it is surely one of the most important exposures ever taken.
School children across the country and scientists around the world lobbied in support of one last HST servicing mission. In 2005, NASA administrator Michael Griffin gave his approval for one more flight in 2009.
That final upgrade improved the telescope’s sensitivity across expanded wavelengths, paving the way to new Hubble Ultra-Deep Field and “Pillars of Creation” images, better observations of asteroids, comets, planets and moons of our solar system, the stars and nebulae in our own galaxy and others — and pretty much everything else.
In 2011, the Space Shuttle fleet was retired. With it went our ability to upgrade or fix the HST. Currently, the Hubble Space Telescope is operating with just one of the three gyroscopes it originally relied on for precision targeting, the equivalent of hitting a dime with a laser beam from 200 miles away. It is otherwise in remarkably good shape.
NASA’s sophisticated James Webb Space Telescope has a mirror 2.7 times larger than Hubble’s, and its cameras “see” in the infrared rather than visible light. Webb’s sensitivity to heat radiating from Earth required that it be parked about 1 million miles away — too far for repair if anything goes wrong.
JWST is more advanced, but not a direct Hubble replacement. The HST is old, but functioning and producing valuable science. Despite some overlap between the Hubble and Webb, they mostly compliment each other, and their data is routinely combined.
NASA hopes to operate Hubble into the next decade, but eventually will need to guide the silvery cylinder to a safe re-entry and fiery demise. That will be the end of a legend.
Find rise and set times for the sun and moon, and follow ever-changing celestial highlights in the Skywatch section of the Weather Almanac in The Republican and Sunday Republican.
Patrick Rowan has written Skywatch for The Republican since 1987 and has been a Weather Almanac contributor since the mid 1990s. A native of Long Island, Rowan graduated from Northampton High School, studied astronomy at the University of Massachusetts-Amherst in the 1970s and was a research assistant for the Five College Radio Astronomy Observatory. From 1981 to 1994, Rowan worked at the Springfield Science Museum’s Seymour Planetarium, most of that time as planetarium manager. Rowan lives in the Florence section of Northampton with his wife, Clara, and their cats, Eli and Milo.
