Sullivan was the first American woman to walk in space.

Star Bound №10: Handprints on Hubble

Bruce McCandless III
7 min readJun 3, 2022


Reading Astronaut Kathy Sullivan’s Stainless Steel Memoir

Most astronaut books are about, well, astronauts. Where they came from. What their parents were like. Who they married, why they divorced, and how much they like airplanes.

By contrast, Kathy Sullivan’s new book Handprints on Hubble: An Astronaut’s Story of Invention is as purposeful as she is. It’s the story of her career at NASA, of course, but it focuses consistently on the projects she was assigned to, worked on, and came to love. To subvert an old advertising phrase, it’s more about the steak than the sizzle.

Sullivan joined NASA in 1978 as part of the largest astronaut class to date, Group 8, the “Thirty-Five Fucking New Guys.” She made history as the first American woman to do an EVA — an extravehicular activity, otherwise known as a spacewalk — when she performed the feat on Shuttle mission STS-41-G in 1984. As exciting as that accomplishment was, the bulk of Handprints relates to her work on the Hubble Space Telescope, the world’s most successful orbiting astronomical observatory. Originally the plan for prolonging Hubble’s lifespan involved periodically retrieving and returning it to earth on NASA’s new “space truck,” the Shuttle, for upkeep and repairs. But somewhere along the line, as it became clear that the Shuttle was not going to be quite as frequent or as cheap a flier as envisioned, a decision was made that Hubble would need to be fully maintainable in space — i.e., while it was in orbit.

This was a revolutionary concept, and the practical problems were formidable. Think of it this way. You and your fellow taxpayers have just paid over a billion dollars to create an innovative, highly-sensitive piece of machinery that scientists all over the world hope will give humankind an unprecedented understanding of our place in the universe. If anything goes wrong, the machine will have to be fixed where it’s found — and you’re part of the team of people trying to figure out how this will happen, given that Hubble will be three hundred miles above the earth, in an environment that will kill any living thing that isn’t wearing a pressure suit, and any tool you use will go floating away into the cosmos the moment you set it down.

Add to these challenges the problems inherent in working on anything that’s been designed so that lots of important parts fit in a very small space. As Sullivan has said elsewhere, working on Hubble’s Main Power Unit is a little like trying to change the spark plugs in your car while wearing two snowmobile suits, a pair of mittens, and a bucket over your head.

For the next several years, , including those bad blue days following the Challenger disaster in 1986, Sullivan and fellow astronaut Bruce McCandless II spent countless hours with engineers and technicians from NASA and aerospace contractor Lockheed Martin, planning and practicing how to make maintainability happen. A NASA engineer and native Mississippian named Jean Olivier had dreamed up an architecture for the telescope in which systems were housed in modular units around the cylindrical body of the satellite. A great start: but how, exactly, to get at and into these units?

Ensuring Hubble would be fixable in orbit was literally a nuts-and-bolts project, involving unheralded but brilliant engineers and technicians like Olivier, Michael Withey, Ron Sheffield, Frank Costa, and dozens of others. (In fact, one of the first steps in the process was to figure out which bolts to use. In the end, the team settled on a double-height 7/16-inch bolt with a hexagonal head.) McCandless developed a space tool tethering system, still known as the “McTether,” that simplified and eased the ways in which astronauts could transport and use tools in space. In order to work on the telescope — to turn a wrench, for example — an astronaut would need to be able to anchor his or her feet in order to apply torque. Sullivan and McCandless worked to improve a proposed astronaut anchoring platform — it became the “Adjustable Portable Foot Restraint” — and Sullivan came up with a semi-rigid tethering system for astronaut Sherpa duties, including lugging the Adjustable Portable Foot Restraint from the Shuttle to a satellite work station. Descendants of these pieces of hardware are still used by astronauts on EVAs to this day.

The Hubble deployment mission, STS-31, left earth on April 24, 1990. Deployment was problematic. Astronaut Steve Hawley had trouble plucking Hubble from Discovery’s payload bay with the spacecraft’s robotic arm and lifting it “above” the shuttle, where ground control could activate it. Then, once this act of positioning was achieved, one of the satellite’s two solar arrays failed to deploy. The arrays are sheets of solar cells that collect energy to power the satellite’s operations. A major innovation in Hubble’s design was to attach the cells to a flexible “sheet” that could be rolled and unrolled around a central drum, like a window blind.

As clever as the concept was, it didn’t work as planned. As time wore on and the problem persisted, Sullivan and crewmate McCandless were instructed to suit up for an EVA to manually deploy the errant array. They started the process of breathing pure oxygen to purge the nitrogen from their bloodstream, standard procedure for any spacewalker entering the vacuum of space. After several attempts at troubleshooting, however, engineers on the ground finally figured out that a faulty tension monitoring module was preventing the roll-out of the balky solar array. Once this was fixed, Sullivan and McCandless received orders to stand down. Ironically, the Hubble was deployed while they were still in the payload bay, pressure suited and waiting to begin their repair mission. They missed the activation of the satellite they’d both worked so hard to bring to life.

Hubble’s deployment seemed to represent a triumph for NASA, but the good feelings were short-lived. The telescope’s main mirror had been manufactured incorrectly, and was sending back scientifically valuable but decidedly sub-optimal images from space. It wasn’t that the mirror was flawed. It was perfectly ground — but ground to slightly wrong specifications. Once the defect was made public, the American press howled with derision. Hubble quickly went from being a symbol of success to the embodiment of technological (and financial) folly.

But here’s where NASA’s “maintainability” work proved its worth. Hubble could be fixed. In 1993 a Shuttle crew led by Story Musgrave installed additional small mirrors to correct the main mirror’s faulty vision. As a result of this and several other servicing missions — Hubble was, indeed, fully maintainable in space — over the years, the apparatus continues to function even today. It flies 340 miles above the earth’s surface and orbits the planet fifteen times a day. It has captured stunning snapshots of galaxies previously undreamt of, and allowed us new insights into the nature of the universe and how we got here — and, maybe more importantly, where we’re going.

Among the discoveries and confirmations Hubble has facilitated are the surprising — and somewhat alarming — fact that the universe is not only expanding, but in fact expanding at increased velocity; that the universe is around 13.7 billion years old; that black holes do in fact exist, as astronomers and physicists had previously postulated, and may in fact be at the heart of most if not all galaxies; that Pluto has a fifth moon; and that orbiting the sun even beyond Pluto is a giant, potato-shaped rock called Arrokoth.

Hubble allowed astronomers to watch Comet Shoemaker-Levy 9’s kamikaze crash into Jupiter and has detected what seems to be a massive saltwater ocean under the ice of Jupiter’s moon, Ganymede. It has also found what star-watchers believe to be the most distant galaxy ever observed, the mysterious GN-z11, located some 32 billion light years away in the constellation Ursa Major. One source reports that over 18,000 scientific papers have included data from Hubble. Almost as important as the science is the beauty. Data counts, but so do diamonds. The images Hubble has sent back to earth astonish even jaded sky watchers, much less those of us who wouldn’t know dark matter from Darth Vader. We goggle at sights like the odd, hourglass-shaped Southern Crab Nebula, several thousand light years away; and the shimmering pillars of the Star Queen Nebula, extended like fingers on the hand of God; the teeming galactic petri dish of the Hubble Ultra Deep Field, every one of its points of light a million possible and impossible worlds. The size, shape, and sheer spectral weirdness of the images Hubble relays to us boggle the imagination, and make prophets and dreamers of us all.

While Sullivan has called space flight a “magical, crazy, indescribable experience,” Handprints on Hubble leaves little room for reverie. Sullivan is notably reticent about her personal life and feelings. That’s her prerogative, of course, and has no bearing on the science and engineering discussed in the book. Frankly, some other astronaut accounts have offered a little too much personality.

Still, it would be nice to know more about Sullivan as a person, outside the space suit and the neutral buoyancy tank at JSC. What does she read? Who does she love? This quibble aside, Handprints is a valuable, absorbing account of men and women — women and men? — inventing the sorts of real-life solutions to scientific challenges that have allowed us to significantly advance our understanding of the cosmos. If you’re interested in the American space program, and space astronomy in particular, do whatever you have to do to get your handprints on Sullivan’s book.



Bruce McCandless III

I'm an Austin-based writer trying to figure out space, science, and Texas politics. For more, see: