In a darkened room at Nasa’s Goddard Space Centre in Maryland, I found a focused team of men and women, engrossed in their daily task of taking the pulse of the planet’s most celebrated science instrument: the Hubble space telescope. On the wall in front of them a live 3D rendering of Hubble is projected onto the wall – its orientation and position in orbit 550 kilometers above the Earth presented in real time for everyone in the room to see.
Today Hubble was being harnessed to hunt for distant icy dwarf planets, which Nasa’s New Horizons mission might be able to aim for later this year, after its historic flyby of Pluto. Such objects, found in the remote Kuiper Belt, over 4 billion miles from Earth, are typically only half as big as Long Island, NY, and so dark in colour that only Hubble’s exquisite mirror has a chance of detecting them.
When a giant space telescope was first seriously proposed in the 1970s, Nasa insisted that its primary mirror had to be the largest, smoothest piece of glass ever created. The polishing team at Perkin Elmer did such a perfect a job of making it smooth that had their 2.4metre-wide mirror been scaled up to the width of the Atlantic Ocean, no bump on it would be greater than four inches high.
Such unprecedented smoothness took these devoted optical engineers over three years of polishing to achieve; often working around the clock, seven days a week. Such commitment to the job would be at the heart of Hubble’s success in the decades that followed, as their mirror was repeatedly called upon to capture the faintest of light from some of the most illusive and distant objects in the universe.
Indeed, the craftsmanship of Bud Rigby and his polishing team was so ahead of its time that the new digital camera technologies inserted into the telescope by subsequent space shuttle servicing missions would not match its precision until 2009, some thirty years after the mirror had been manufactured.
But in the months that followed Hubble’s launch in 1990, with the discovery that their mirror had been made very slightly too flat at its edges, the perfection of its smoothness – and their dedication to making it so – was quickly forgotten. Twenty-five years on, I found Rigby and his friend and colleague from Perkin Elmer Lou Montagnino reluctant to take part in our film, still sore from the mauling they’d repeatedly received over the decades from the media.
Yet it was only thanks to their tireless work on the project that the flaw in the shape of Hubble’s primary mirror could be corrected so completely. The fact that the telescope remains at the cutting edge of cosmology, a quarter of a century after its construction, is a tribute to their outstanding skill.
Days before my visit to Hubble’s control room I’d sat with Rigby in his home in Connecticut and contemplated just how far back in time his mirror had now allowed us to see. In the top left-hand corner of the aptly named Hubble Ultra Deep Field image (re-released by Nasa a few months before) is a small red smudge of light called UDFj39546284, made from light that’s traveled through space for most of the history of the universe.
“Just stop and think about it”, reflects Rigby. “This is this is light that left billions of years ago and it’s now in our possession. We’ve seen it! The size of the universe is expanded hundreds and hundreds of times in just one sighting. It’s proof in my eyes that we built a telescope that was better than any on the Earth.”