1080 Across the universe with Hubble

Not Yet Imagined: A Study of Hubble Space Telescope Operations
by Christopher Gainor

Washington, DC: National Aeronautics and Space Administration, Office of Communications, NASA History Division, 2020

9781626830615
free eBook (PDF) available here

Reviewed by John Hutchings

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This is a scholarly but very readable tome that describes — in some 450 pages — the story of how the Hubble Telescope has operated in orbit, published to mark its 30th year of operation.

The Hubble Telescope, known widely as HST, is probably the most famous astronomical observatory to the general public, and is a precious resource to the many professionals who have made use of it. Many books have been written about it, and its prodigious publicity machine has made it a household name around the world.

Chris Gainor’s Not Yet Imagined picks up where Robert Smith’s account of the building of the HST left off (The Space Telescope: A Study of NASA, Science, Technology, and Politics), but does reprise enough of the motivation and back-story to allow the reader to appreciate how its later operation unfolded. The nine chapters of this book give excellent and well-illustrated accounts of the stories behind the problems and successes of HST’s thirty years of operation, and a peek into the future.

While the public had much exposure to the story of the mis-figured primary mirror discovered when HST first began its life in orbit, and the subsequent spectacular success that it enjoyed later, the Telescope had many near-death experiences, both technically and politically, and Chris’s book gives a detailed insider’s view of the almost endless drama that lay beneath. Hubble and the Space Shuttle are inextricably linked in the story, in both the launch and the many servicing missions that followed.

HST was designed to be serviced by the shuttle. The advantage, as it happened, was huge. Without that, it would have died very early and never produced the science it was designed for. In fact, the advance of technology allowed HST to be refurbished more than once with instruments literally thousands of times more capable than the initial ones. It also allowed astronauts to replace failed or malfunctioning components, such as the guiding system, solar panels, insulation, power supplies, and more. The disadvantage was the necessary low orbit, which meant the earth blocked out more than half the sky at any one time, as well as problems from the radiation belts, atomic oxygen corrosion, microscopic debris impacts, and orbital decay. Also, the scheduling of observations is complex and inefficient in low orbit.

A large part of the story is of funding. The many servicing missions and the generations of new parts and instruments were costly, and the budget was tight. While Hubble was rescued and improved multiple times over the thirty years, it came at cost (up to some 20 billion in real year dollars, depending on accounting for the shuttle missions and inflation over the decades, but totalling many times the original launch price). It is interesting to note this greatly exceeds the 8-9 billion dollar price tag for the JWST, which has been much criticized for cost overruns. The book relates the budgetary struggles, chapter by chapter, and gives much detail on the many persons and groups involved, their sometimes conflicting points of view, and their rivalries.

It is difficult to build anything as complex as HST to begin with, but added to that is the need to have it all work perfectly when turned on in the harsh environment of space, and build in redundancy and fail-safe provisions to ensure against unforeseen events in operation. The book gives us a good insight into that, and to the many unanticipated problems that nevertheless arose in orbit.

Operating the telescope from the ground involves telemetry of commands upwards and data downwards, on a continuing basis, 24/7. We are given a good account of the technical challenges on the ground, as well as the processes of selecting and refining from the many scientific investigations proposed by the scientific community. In many ways HST defined “robotic” observations that are now common, even in ground-based facilities.

This reviewer was personally involved in the HST program for much of the time, as a member of two instrument teams, as an active scientist, and participant in many of the NASA committees involved (incidentally the only Canadian who was). So, while much of the book relates things that I was witness to, there are two main personal reactions. First, the book, commissioned by NASA, gives very much the NASA-centric view of the story. Second, and as a consequence, a number of opinions, decisions, and others involved are not mentioned. Perhaps just as well — as it is, the reader gets a very good impression of the difficult personal, technical, and political issues involved.

The book includes a foreword by NASA astronaut/administrator Charlie Bolden, a preface, a prologue, and a conclusion, all covering some 26 pages, in addition to the core text of 270 pages. I am reminded of the old adage for giving technical talks: say what you are going to say, then say it, then summarize it. In fact most of the chapters stand on their own, having just enough overlap to make them so. In addition to the main text, each chapter has copiously detailed “end-notes” for reference and background. These cover another 60 pages all-told. Several appendices give numerical details of costs, proposals, instrument use, and publications that span the 30 years. Finally, there are 70 more pages of references and a thorough index. Thus the book serves as a scholarly and complete reference work as well as being easily readable by those with more general interest.

The servicing astronaut crews and their exploits are described in vivid detail, and give an excellent insight into the difficulties, training, and ingenuity in their heroic missions. We are introduced to the directors of the Space Telescope Institute and their particular contributions to Hubble’s history, as well as many of the senior NASA managers in the program. We read less of how they reached their decisions, and how they were advised by the many committees and contractors who are still an essential part of running the program. Every instrument that has flown on Hubble is summarized in 1-2 page inserts, although each one if them has a history that could fill a chapter, on the years of design, technical development, crises, testing, calibration and software development before they were delivered as turnkey items for installation. Not to mention the fierce competitions to have them selected in the first place.

This is not a book that delves deeply into the scientific details and images that exist in other publications, and the press-releases from HST. The results of the initial “key projects” are covered, making sure to give due credit to other telescopes and facilities that were also involved. While the story is related of how the Hubble Deep fields were conceived and executed, not much is said of the many science results that emerged.

A chapter covers the early images after the optics were corrected, and notes their impact both with the public and professionals. What is missing is more of the infrared imaging that came later. A key comparison of optical and infrared images of the famous “pillars of creation” is tucked away in a later chapter (p. 337). The book also omits reference to, and illustration of, the many spectrographic results that have also had lasting impact on our understanding of cosmic phenomena. From these we have learned details of the conditions and dynamics around massive black holes, for example. Another story omitted was the early claim of “naked quasars,” which contradicted the findings from ground-based telescopes that showed quasars to be nuclei of often-disturbed galaxies. This was later resolved by more careful processing of the HST images — an interesting lesson in how careful we have to be, even with HST data, for robust results.

The big stories told are of the diagnosis and correction of the flawed main mirror, and the on-again off-again last servicing mission. These fill three chapters of the book, and offer fascinating detail of how decisions were made, who made them, and the astronauts who pushed the boundaries of spacewalking experience to carry them out. But the rest of the story is good reading, from other new instruments, to the complex ground systems, and how scientists around the world have made use of Hubble, and its huge archive of data, which already accounts for more investigations than new observations. It is an epic saga, worthy of the detailed attention and the well-written account by Chris Gainor. It’s a book that will interest many: nice work.

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John Hutchings is an astronomer whose research has ranged from hot stars to black hole binaries and quasars. He has used telescopes around the world and in space, and from X-ray to radio wavelengths. Born in South Africa and a graduate of Cambridge University, he has been based at the Dominion Astrophysical Observatory in Victoria since 1967 and has worked with colleagues and space agencies around the world. He led Canadian participation in a series of key missions, including the International Ultraviolet Explorer, the Hubble Space Telescope, the Far Ultraviolet Spectroscopic Explorer, Astrosat and the Ultraviolet Imaging Telescope, and the James Webb Space Telescope. He is currently working on new space observatories for Canadian participation. He also writes mystery novels based on his travels — stories about ordinary people who get involved in adventures beyond their normal experience, from shady dealings in the wine trade (A Fine Drop, 2011) to difficult situations on coastal British Columbia (Death in Remote Places, 2013) and South America (The Clue from Cusco, 2017). John lives in North Saanich. Editor’s note: John Hutchings has also reviewed books by Bob McDonald, Joel Scott, Peter Vassilopoulos, and R. Peter Broughton for The Ormsby Review.

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