Ever wondered how tribology works in space? From the moving parts of a satellite to a rover exploring distant planets, tribology plays an incredibly important role in the space industry. As this week is World Space Week, we thought we should talk to someone who knows just how important tribology is up among the stars. We had a chat with Dr. Michael Buttery, principal project scientist at ESR Technology – a dynamic company known for its expertise in addressing diverse engineering challenges, particularly those in the realm of space exploration and technology!
- Could you tell us a little about what ESR does, and your role within the company?
That’s always an interesting, difficult question to answer because what ESR does is so diverse. The company has existed for about 20 years now, and it came about through the restructuring of the UK Atomic Energy Authority. About 20 years ago, the Atomic Energy Authority was encouraged by the government to get rid of some of the parts of the business. It got rid a lot of its engineering consultancy businesses, that were all kind of cast adrift and basically someone made the decision to combine all these different parts together into a company. The commonality amongst all of us is engineering, safety, and risk – which is where the ESR comes from. Within those groups there was the industrial tribology group, a space tribology group, consultancies for the oil and gas industry and aviation industries, particularly like Civil Engineering for aviation – nothing at all to do with each other. All those companies ended up huddling together. And that is ESR!
So, what ESR does is lots of different things that aren’t really that closely related but have all to do with engineering excellence. Specifically, the bit that I work in is the space tribology group which has existed for over 50 years. It’s been around longer than ESR has, ESR is just the current name we go by, but we were part of the Atomic Energy Authority and before that we were part of another company. It just so happens that right now we are part of the company ESR technology.
The short answer of what ESR technology does is where we’re an engineering consultancy group in a wide range of fields, and much of that is mechanical engineering and tribology.
- How did you end up working for ESR, and in STEM fields in general? Was science always a passion of yours?
I went to university to study astrophysics, specifically Galactic astrophysics. My dissertation was what happens when galaxies smash into each other – nothing at all to do with engineering in any way, shape, or form! But I’m a geek, and I like space, and when I finished my master’s degree when I was 21/22 and looking for a job, I found this company that basically builds, tests, and designs mechanical bits for space. For someone like me, who’s a bit of a geek, I thought that was fantastic. I understand a little bit about kind of applications of space – not necessarily kind of the hardware side – but I thought it was interesting, applied for a job as a research scientist, and, and was given the job!
I think although I didn’t know the subjects and I didn’t know engineering, I knew how to do research projects. And I understood the kind of the concepts of playing with variables, how you construct a test program, how you analyse data, how you communicate things, that kind of thing. So, although the subjects that I’d worked in weren’t particularly applicable, it didn’t really matter.
And that was 15 years ago and I’ve basically a bit of picked up some engineering over the last 15 years. Most people come here from mechanical engineering backgrounds, either master’s or PhD level, but given that space tribology is quite different from terrestrial tribology, we’re not too worried about how applicable people’s knowledge about the subject is. Because what we do is so diverse, they’re going to have to learn anyway. Instead, we look for the right people, rather than people who’ve done the right thing.
- Picking up on what you said, how is tribology in space different from terrestrial tribology? Are they fundamentally different from one another?
Short answer is there are lots of small differences between the operating conditions on ground compared with space. But the small differences manifest into quite significant impacts on performance. An example is the presence of moisture. On the ground where, chances are, you’re operating in air; you’ve got moisture present. That moisture is going to interact with your contacting surfaces in a certain way, whilst in in the vacuum of space, you hopefully don’t have moisture present. Which means that your lubricating properties are going to be completely different, your wear properties are going to be completely different.
Take graphite as an example. As a lubricant, it works fantastically well. It’s used in lots of applications on the ground, but it requires moisture to work well. So, in a space application it won’t work at all. You’ve also got things like evaporation rates to contend with, because in the vacuum of space, if you’re using an oil or fluid lubricant it’s going to evaporate at a significantly faster rate than it is on the ground. Which means that the oil that you’d put in your car engine, that’ll stick around for a long, long time on the ground. In a spacecraft, it’s going to evaporate in seconds. You’ve got that to contend with. It’s basically understanding the fact that you’re operating in an entirely different environment, an entirely different condition.
The department that I work in, and what we do in the space tribology group is specifically about answering those questions. It’s about providing support for the space mechanisms industry and saying, “these are the sorts of things you need to think about. This is how it’s different from terrestrial engineering. Maybe you need to use different materials, maybe you need to use a different oil, maybe you need to do this to it instead; things that you wouldn’t normally need to do.” It’s that kind of stuff.
- It seems very obvious to me now that that space is an entirely different environment to Earth, that’s just never occurred to me. That’s really interesting!
I mean, there’s the fact that you’re operating in a zero G environment – or micro-gravity is more accurate to say. This is an influence as well, because it means the way that the lubricant moves is completely different. The fact it’s inaccessible causes, let’s say programmatic problems. If something breaks on the ground, you go and fix it, if you need to re-lubricate something by slopping some more grease on it you probably can. It’s a little bit more difficult to do that when it’s on a space telescope.
That sort of fundamentally changes the way that you approach your test campaign and your validation campaign, because you’ve got to be 10 times surer that it works before you launch it. Because if it doesn’t work, the consequence is so much larger. All that risk management is, is the chance of something happening multiplied by the impact or the cost-impact of it happening. Well, space tribology isn’t any harder than terrestrial tribology. But I would argue that the impact is probably higher because you can’t get to the thing to fix it. Which means it becomes riskier, which means you’ve got to put more effort into solving the problem.
- So, what drew you towards space tribology specifically, other than a general love for space?
What we do is no different from what a lot of other mechanical engineers do. Mechanical Engineering is of course very, very fun and a very interesting thing. But the thing that’s specific about space engineering is that when you’re having a difficult day and things aren’t working, the fact that whatever you’re working on is going into space – a space telescope, or a rover that’s going to go on the surface of Mars, or going off to surveys on icy moons around Jupiter – it helps you get through the difficult days. If you’re wired in that way, there’s quite a lot of job satisfaction in knowing that the things that you’re working on is in space! There’s a lot of people that work on railway bearings – there’s not a lot of people that work on space telescopes.
- I realise you probably can’t talk a lot about what you’ve specifically worked on, but are there certain things you take particular pride in having worked on, or having been able to do at ESR?
From a professional point of view, I think the things I’m happiest about and the most proud of are things like the training courses, and specifically there’s been instances of going over to give lectures to NASA, about how to do space tribology and how to understand things. That gives me a lot of pride. I was over at the states during a shuttle launch, for instance, that was able to coincide with one of those visits!
I think it’s true to say that the company has worked on every single mission that the European Space Agency has been involved in, ever. You name a spacecraft that ESA has been involved in, and in one way, shape or form it’s come through our company, and I’ve been at the company for 15 years!
The things that I’m probably the proudest about that I can talk about are the conferences and training courses. For a small company that’s based in Warrington in the UK, to be invited over to present at the Goddard Space Centre for NASA, that’s one that’s always high on the list.
- Since you’re obviously quite involved in space tribology and engineering, are there any interesting new trends going on in those research areas?
In space tribology and space engineering, in general, people are just as interested about additive manufacturing as they are everywhere else. I think it’s a really interesting idea when people are talking about going back to the idea of Moon bases and habitats.
For me what’s interesting is when you think about what they’re going to make them out of, because they’re not going to launch those materials from the ground; they’d launch 3D printers. And then they’re going to make everything that’s there from lunar regolith. From a tribology point of view, if you’re building a hinge of a door, or the bearings of your lunar rover, you’re going to 3D print those parts from lunar dust.
I imagine you would probably do your production of everything in situ. And what you would do is you would send your additive manufacturing parts, and then you would make stuff from the piles of abundant material that’s laying around, because otherwise it would just be impractical.
What are the mechanical properties of additive manufactured structures made from lunar dust? Coupled with the advances in additive manufacturing, if you put that and lunar dust engineering together, you’ve got a whole world of engineering research that no one has gone anywhere near yet! Because all our current research is based on steels, ceramics, etc.
- That’s amazing! Are there any other areas of research around space engineering and tribology you’ve found personally interesting recently?
I talked before about the fact that a lot of materials – and a lot of the lubricants in particular – operate only in a vacuum environment, where they don’t have the presence of moisture. Well, it’s not only the case that they don’t work in the presence of moisture like graphite, but can actually be even worse than that, in that when they are operating in the presence of moisture it destroys them! This causes the problem of how do you test it?
If you’re building a gearbox that’s going to go on a solar array drive mechanism that’s going to go on a spacecraft that’s got to work for 15 years – how do you show it works? There are a lot of loops you’ve got to jump through. It basically means you’ve got to construct vacuum chambers; you’ve got to make sure you control your environment very, very carefully. If you can identify mechanical solutions that are robust against environments and will work equally as well on the ground as they do on space, it makes the demonstration of that much easier. So, graphite; fantastic in one environment, but terrible in the other. There’s lots of lubricants that are fantastic in space, but terrible on the ground. If you can find one that’s equal amongst both, then then it makes the de-risking of that solution much easier.
And I suppose the third thing that I would focus on for future is this concept of, what we call new space against old space. To give a bit of context, old space is the idea that space is the thing you’re trying to do. It’s about building a satellite, a telecommunication satellite, a rover.
New space is the concept that the industry uses space, but space itself isn’t the commodity. So maybe you are launching 300 satellites, because you want to provide 5G Internet coverage to some remote environments, and you just happen to do it via space. Or maybe you are wanting to have a tourism business and your tourism businesses is to travel into space. Space isn’t the thing you’re doing. It’s just the means by which you achieve it.
Virgin Galactic and SpaceX are new space, NASA is old space. And the transition between the two is quite different. Because if you’re building a satellite to go survey the icy moons of Jupiter, you’ve got to be pretty sure that thing works. And you’ve got to be pretty certain to demonstrate that it works.
If you’re building 300 satellites to go and provide 5G coverage to some remote rainforest, if a couple of those satellites or launches fail, you don’t really care, because you’ve got so many of them. This is why SpaceX don’t care when their rockets explode, because they’re launching hundreds of the things. And that fundamentally changes quite a lot of the approaches.
So, what it means is things like developmental times massively come down. Because you don’t have three years to work out a solution anymore. Because if you’ve got a competitor, three years is suddenly a much shorter timescale. It means that you can take riskier solutions, because if 1% of your launches fail, that’s a more acceptable loss. If 1% of launches of launching a space telescope fail, probably isn’t an acceptable loss because you’re only building one telescope. And if that’s the one that blows up, you’re in trouble. But if you’re building constellations of hundreds upon hundreds of tiny little satellites, then that’s okay.
- The idea of new space vs old space must be a very recent development in space engineering then?
It’s only appeared really the last five or 10 years, but there has been quite a few industries like Virgin Galactic and SpaceX and a few others, where the way they are approaching it is very different. This is why when a SpaceX rocket explodes, they don’t care, because there’s another one behind it, they become acceptable losses. Obviously, you still want to prevent it if you can, but it means that you’re going back to the thing about risk being likelihood multiplied by impact.
Impact is completely different for 300 5G satellites than it is for a space telescope. Which changes your whole philosophy to how you approach the engineering solution. It’s something that space industry science has to grapple with as well, because for the last 50 years, it’s always worked in one way. And now it’s having to change it and approach in a different way.
- You recently made upgrades to a PCS Instruments MTM, to allow it to create a vacuum environment. Why did ESR choose the MTM for sort of the research you’ve been doing?
Basically, we had both ends that the MTM could achieve. So, the MTM does three things. It does rolling, and we had we had a rolling tribometer that operates in vacuum. It does sliding, and we have a sliding tribometer that operates in vacuum, and what we wanted was something where you could vary it, because you get results at one end of the scale you get results at the other end the scale, but we wanted to know what happens in between. And when we’ve needed an MTM, we’ve gone to various universities and have made use of them.
But none of them run a vacuum. And of course, to simulate the environment that we’re simulating – and it is important to simulate – is vacuum. Imagine three points of a triangle, you’ve got vacuum at the top, sliding in one corner, and rolling in the other corner. We only had access to machines or our own machines that do two out of those three. But what we didn’t have was one that did all three, which what the MTM can do!
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