s the “final” servicing mission approaches, once again we hear the Hubble Space Telescope has no future. Ground-based telescopes, with adaptive optics to counter the atmosphere’s turbulence, soon will leave Hubble in the dust. Using NASA’s new human spacecraft, the Orion crew exploration vehicle, to undertake additional maintenance missions – following after the last shuttle flight to Hubble, currently planned for August – would take resources better invested elsewhere.
We have heard similar arguments since before Hubble was launched, and yet 18 years later, the queue of astronomers waiting to use this unique instrument extends around the proverbial block. If those belittling Hubble were crying wolf – even if by some chance they were right this time – by now no one should be listening. Why do so many in the space community take these voices seriously? Part of the answer involves a related, contradictory bias, often shared by the same people. Hubble is somehow “better” than the human space program, presumably meaning that the latter should be cut in favor of the former.
In fact, the Hubble Space Telescope is an intimate part of the human space program. Hubble’s many discoveries, extending from the solar system almost to the probable edge of the universe, should be considered key examples of the scientific results many claim that human spaceflight has failed to deliver.
If Hubble had been an exclusively automated mission, it would have been an utter failure from the moment it was launched with a near-useless mirror. The hard work of the astronauts and supporting staff who installed the correcting optics that saved the day, and the scientific results they enabled, fail to get fair credit as a product of human spaceflight.
Some Hubble astronomers claim that, after astronauts installed generations of new instruments and made repeated repairs and improvements, the telescope is some “90 times” as powerful as it was just after the corrective optics finally made it a useful instrument. If so, every single point of improvement, and the results so obtained, are products of human spaceflight.
Similar biases are visible elsewhere in the space program. Since the major results in the international space station project are in the fields of engineering, space construction, fluid and solid state physics, and human and non-human biology – and not much in astronomy – the space station appears “scientifically useless” to many scientists. Even though Apollo was hardly optimized for science, the project’s incidental geological surveys remain to this day the benchmark by which the rest of the solar system is measured. The absolute cratering rates that are the single most valuable product of planetary science so far have come out of a human project.
If opponents of human space science have to make their primary case by defining all our astronauts’ discoveries and achievements as “not science,” they need to re-examine their case. Hubble is one of the most productive scientific instruments ever deployed – one of the wonders of our age. The characteristics that make it such a success – permanence and constant improvement – are enabled by astronauts.
None of this proves it is worth the undoubted expense of repairing Hubble again, or of building new human-tended space telescopes. Human spaceflight is expensive and scientists are only human – many want quick partial results soon. They are less interested in investing in the skills – the ability to build and repair giant instruments in microgravity and to send geologists to the planets – that will provide a more full understanding for future generations.
Understanding the solar system, let alone the universe, is a long-term endeavor. It cannot be rushed, or done on the cheap. Yet, if past experience is any guide, two of the smartest and most important decisions NASA made in recent years are among the simplest and least expensive to implement. These are to install a docking ring on the next, and supposedly final, Hubble repair mission later this year that Orion could use; and to install a similar ring on the next generation James Webb Space Telescope.
By enabling the option of repair, NASA is leaving open the possibility that both of these instruments could be productive far into the future.
The final decision on whether to conduct such missions should be made without the anti-human bias so prevalent in space science today.
Both automated and human spaceflight have vital roles in our efforts to understand the solar system. Without the former, we could not have conducted our initial quick-look reconnaissance of the larger bodies orbiting our star in only five short decades. Without the latter, we will never build the large-scale permanent orbital instruments and conduct the detailed geological field work needed to truly understand the many accessible worlds of our solar system, and their places in the universe beyond.
Donald F. Robertson is a freelance space industry journalist based in San Francisco.