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The Voyager Sculpture: A Golden Record Of Human Achievements

NASA's Voyager 1 spacecraftA brief article about the nuts and bolts of creating a bronze sculpture to tell stories of human achievement and the beauty of the natural world. From earthbound engineering to cosmic explorers, artist and engineer Alex Kirkpatrick walks us through some of the techniques behind, and the evolution of, his passion project of the last few years.

Inspiration And Aims For The Project

In the 1970s NASA launched four spacecraft that would explore the outer planets and on to the interstellar void beyond. Each of these craft carried messages, etched into Golden Records, explaining who had sent them and where they had come from in case they were ever found by intelligent life.

In September 2013 Voyager 1 became the first human-made object to leave the solar system.

"The spacecraft will be encountered and the record played only if there are advanced space-faring civilizations in interstellar space, but the launching of this 'bottle' into the cosmic 'ocean' says something very hopeful about life on this planet." - Carl Sagan

The original Golden RecordInspired by these first interstellar messages from humanity, showcasing the diversity of life and culture on Earth, I imagined a pair of bronze sculptures - a man and a woman.

I began collecting examples of scientific and technological progress charting the course of human development, from early number systems and geometry to Nobel prize winning research and unsung heroes. This historical archive of equations and diagrams would be engraved into the surface of the sculpture - the ‘skin’ of human existence.

These new ‘golden records’ would show our voyage of discovery from the beginning of time to the unknown future ahead of us, and in reference to classic creation myths but with a scientific spin, I nicknamed them Atom and eV.

As I write this in December 2021 the project is still in progress, but my hope is to exhibit the sculpture at a venue that celebrates the superposition of art and science; the creativity that stems from, and feeds into both, and that also grasps the precarious situation we technological beings find ourselves in.

The Golden Record inspired the inscriptions on Alex's sculpture

The Underlying Message

In 2016 I finally started work after the death of my grandfather, a maths and physics teacher who inspired a love of science in not only myself, but many other people. However the themes of the project had slowly changed as, over the years of researching the discoveries celebrated in this work, an underlying counter-message had become clear.

Alex's 'Gramps' who inspired his love of scienceTo date there are over 500 breakthroughs and achievements inscribed on the sculpture, but I have lost count of the number that were overlooked or misattributed. This feeling was only compounded by my partner reading, and often reading aloud, the book “Invisible Women” by Caroline Criado-Perez. The book reveals systemic biases against women and the sections on medical research and technology in particular hit a little close to home for my own project. I know Accu has written about similar issues of misrepresentation and historical gender bias within the scientific community in their article discussing the importance of celebrating International Women In Engineering Day.

By this time I was already struggling with the technical nature of sculpting intricate human figures and these new doubts about my message of simply celebrating science began to weigh on my mind. So, I realigned the focus of the project, echoing one of the latest theories in cosmology Lambda-CDM, and those earlier nicknames bore unexpected fruit. The foundation of this theory is that visible matter - atoms - make up only ~5% of the universe, and the vast majority is unseen.

Alex's initial model for the plinth the sculpture and absent presence will stand onThis is currently referred to as Dark Matter and Energy (n.b. energy is often measured in electron volts or eV, the early nickname for the bronze woman). Much of the pioneering work was done by Vera Rubin, studying their interactions with gravity on galactic scales and the way forward to a more relevant message now seemed obvious.

The man will stand on a plinth sized for two, its black granite warped by his mass. While beside him, in stark contrast, another invisible presence - detectable only by their footprints and their influence on the fabric of space-time.

This physical impression into the plinth may be subtle but the negative space above, and its implication should be clear; an admonition for our past and a space on equal footing for our future. I still wish for it to be an uplifting Humanist sculpture, a celebration of science and how far we have come, but the finished piece will explore beyond the great names and Nobel prizes.

It will thematically and literally show the holes left by the forgotten people, the issues of representation, or misrepresentation, in science and the myth of the lone scientist. For me, sometimes an absence is more keenly felt, and asserts a more powerful message, than the neat lines of an argument.

My first attempt at his pose was brash and had other technical issues, so I took this opportunity to make some changes. I pulled him back half a step, took away some of his earlier confidence, and left him poised on the edge of motion, reaching for the stars. It is a representation of humankind’s restless, and sometimes fearful, quest for knowledge and discovery.Nautilus - Alex's bronze seashell series

The figure literally reflects the universe that has created it and that it, at the same time, reflects upon and strives to understand. I have often found myself in awe of the universe, the majesty of galaxies photographed by Hubble, the sheer mind bending absurdity that I exist, and think. I hope he shows some of that childlike wonder and leaves you praying the first small step isn't a stumble.

Physical Design And Engineering Considerations

The major engineering challenges in this project broke down into three categories: The Voyager is first sculpted in clay

1. Creating the main bronze sculpture.

2. Grinding and polishing a metal telescope mirror for the face.

3. Supporting the sculpture on the plinth and the internal armature.

Creating the Bronze Sculpture

Creating a sculpture via the lost wax method requires a sequence of transformations from Clay → Rubber → Wax → Ceramic → Bronze.

A similar path has been traced by artisans for thousands of years and you can follow along with my video series.

Maybe bronze seems like an old school alloy for a modern sculpture when there are so many now to choose from, but it has its ‘Goldilocks appeal’. Soft enough to work by hand but hard enough to take a beautiful polish, easy to cast and to weld, and I’ve used it before in my seashell series of sculptures like the Nautilus. 

Finally the bronze pieces are ready for smoothing and weldingVoyager began with a metal armature which provided support for the soft clay. I made this adjustable and used an oil based clay, which won’t dry out and crack, to allow plenty of time for sculpting (...and resculpting). 

Once satisfied with the clay I made moulds from silicone rubber and plaster around the sculpture. The rubber retains the surface of the clay underneath, while the plaster holds the overall shape. You can also use this stage to divide the sculpture into more manageable chunks.

The moulds are then used to produce wax copies of the initial clay sculpture.It is a similar process to creating hollow chocolate eggs.

Controlling the thickness of these wax pieces is crucial for proper solidification during the bronze casting. Too thick and you run the risk of porosity and shrinkage defects. Too thin and the bronze may solidify before filling the entire piece.

Each wax piece then has further additions of sprues and vents to contain and guide the flow of molten metal. At this point the waxes are dipped in ceramic investment, which is dried before the wax is melted out, leaving a hollow space for the bronze to fill. 

This left me with a bunch of bronze pieces which need welding together to form the original sculpture. Then I needed to smooth and blend the welds before working on the surface finish.

My aim aesthetically was for a polished surface, in line with the original golden records, with the option of gold plating as the finishing touch.


The Telescope Mirror

This took many attempts, a huge amount of time, and became the focal point of the entire project. The result is a rough telescope mirror of the kind used in Newtonian telescopes. I chose the mirrored face to symbolise all of humanity, the tools we use to explore the cosmos, and our place in the universe itself. Should you ever have the chance to look into it (and I would love for this to be possible) you will stand face-to-face with yourself.

To get the crisp, clean finish I wanted, I ended up creating a machine from other projects I’d worked on that was capable of grinding and polishing a spherical mirror. This is fairly standard practice in the amateur telescope industry with a range of machine designs for grinding glass discs. However, performing the same process on a bronze head made the effort much more interesting.

The following video shows the successful process.

The Plinth and Internal Armature

Repositioning the sculptureSculptures, or bronze ones at least, are a little like icebergs; there’s a fair amount going on under the surface. Voyager is cast from silicon bronze, a modern alloy used extensively in art casting and mildly corrosive environments.

At last we have a large metal sculpture but it needs to be placed somewhere people can view it without the fear of it falling over. This is especially true if the sculpture is engraved with fine details that you need to be able to stand close enough to read. 

For day-to-day engineering, I used to buy bolts from eBay, wait a few days for them to arrive and then get back to work. Embarrassingly I did the same on this project and received a pack of A2 grade bolts instead of the necessary A4 (Marine Grade).

It may seem fairly inconsequential but I realised at that moment I was gambling with a project I have put years of my life into. Engineering that level of trust is part of the reason I sourced the major fixings from Accu, I needed to know exactly what I was buying and how it would function, with the assurance that it conformed to the spec required.

Some of the bolts used in the sculpture may well be there for thousands of years and the others are directly responsible for people’s safety.

The cradle inside the leg helps spread the load of the sculptureAs touched on earlier, the wax thickness is critical to the solidification of the bronze during casting. This plays a role in how the sculpture can be fixed in place because you can’t just cast a solid leg in bronze with that thickness.

To get around this, I opted for an internal stainless steel pin running through the standing leg and into the hip region. Here I fabricated a cradle to spread the load from the sculpture into the pin, using a few of Accu’s A4 Marine Grade Flanged Bolts to secure the connection. This alloy was selected for its strength, corrosion resistance and to match the pin and cradle.

At the base of the leg, this stainless steel pin is located into a socket within the plinth. The sculpture’s center of mass is slightly forward, he is about to take a step after all, so the socket body is aligned to take this modest load.

To complete the socket, and allow easy dismounting, I needed a set of High Tensile Bolts to fix the free half, and provide lateral support in concert with a secondary fixing in his other leg.

A socket within the plinth helps balance the structureThe pin and second fixing are electrically isolated from the plinth using Delrin sleeves to reduce galvanic corrosion. Once again, I selected Accu for the necessary Bolts and they arrived the next day. 

As an individual I often struggle sourcing parts from companies who are used to catering to old/ traditional businesses within the industry. This usually entails searching awkward spreadsheets, looking for stock numbers, downloading large PDFs, and requesting quotes.

Let’s be honest, 2021, alongside its other perks, has no place for a company with a confusing website and consequently poor user experience. I’m sure you’ve also felt this frustration at some point and that little ‘x’ to close the tab is just so easy to click.

I really appreciate the effort Accu has put in to make their website clear and provide such excellent customer service, despite the fact I’m only ordering a relatively small quantity of bolts for this project, it really makes a world of difference in reducing stress and wasted time.

They already have one of the team ready to advise on suitable fixings at Voyager's next destination to keep its feet on the ground.

Current Progress and Future Plans

The Voyager from a top down angleThat brings us to now; he’s upright but waiting on some welding, with a fair amount of finishing work to do. I also need to finalise the design for the plinth to be machined.

Once all that is finished I will shift more of my attention to telling the stories behind the inscribed discoveries and securing exhibition space.

My brothers have been planning an augmented/ virtual reality app which can scan the sculpture and provide information about each discovery. We think it might be a little more user friendly than the current few hundred page PDF.

As an amusing aside, before the people at Accu even knew what I was up to here’s a post I made on instagram. It ended with “So we've made it this far, look again at that bolt, it's a really nice one isn't it? Almost worthy of a post of its own…” It seems quite prophetic now!

Alex's Instagram photo praising the quality of Accu's boltsThanks for reading the article - to see how the project turns out you can find me at the links below. If you know anyone who’s interested in science, art, space and equality please share it with them.

Maybe someday a person who worked on the original spacecraft will receive this message, inspired by theirs, and feel a little more pride about how far we’ve come and perhaps how much better our future could be.

Special thanks to Alex Kirkpatrick for writing this guest article for Accu. You can follow the Voyager Sculpture project here:
Alex Kirkpatrick