When the Hubble Space Telescope first launched in 1990, it quickly became clear that something was not right. Images that should have been razor-sharp looked scarcely better than those taken by an amateur telescope on Earth. Once the source of the problem — a microns-thick defect affecting the primary mirror — was identified, aerospace engineers came up with a clever solution: a system of small corrective mirrors akin to a pair of glasses to correct Hubble’s myopia.
Seven astronauts went up in the space shuttle on a repair mission, and after seven days of heroic efforts, the telescope was fixed. Hubble was once again pointed at deep space and began returning the now-iconic images of a cosmos that was, in the words of poet Tracy Smith, “so brutal and alive it seemed to comprehend us back.”
In the decades that followed, Hubble underwent four more astronaut repair and servicing missions. During this time, it unveiled images of incredibly distant stars, revealed supermassive black holes lurking in the centers of most major galaxies, and helped us probe the atmospheres of planets orbiting other stars (exoplanets). Arriving just as the internet was taking off, its stunning images of nebulae and galaxies were shared so widely that they’ve become universally recognizable parts of international culture. It’s now acknowledged as one of the most productive scientific instruments ever built.
The repair of Hubble is a beautiful example of human ingenuity and skill in space. But in retrospect, it was a high point compared to our progress since then. The International Space Station has cost over $150 billion, many times more than either Hubble or its successor, the James Webb Space Telescope — making it the most expensive human-made object in history.
Despite its undeniable contributions to our understanding of life in microgravity, its scientific contributions relative to its immense cost have been questioned. In the meantime, dozens of cheaper robotic spacecraft and rovers have raced across the solar system, bringing back a wealth of data on everything from Big Bang cosmology to the lakes of ancient Mars.
For some, this means we should prioritize robotic missions for the foreseeable future. For others, focusing on the cost of human spaceflight overlooks what they see as the ultimate goal of space travel: making us a multiplanetary species. The steady decrease in launch costs over the past two decades certainly suggests that more ambitious goals will soon become possible if we choose to prioritize them. However, the future of life beyond Earth is not a narrow choice between robotic and human exploration.
To better understand the nature of the current moment, we must shift from a purely humanist perspective to one that recognizes the deep connections between technological civilization and the rest of the biosphere, as well as the history of life up to this point.
Extending life beyond Earth will transform it, just as surely as it did in the distant past when plants first emerged on land. Along the way, we will need to overcome many technical challenges and balance growth and development with fair use of resources and environmental stewardship. But done properly, this process will reframe the search for life elsewhere and give us a deeper understanding of how to protect our own planet.