Working in the biggest laboratory in the universe
Experimenting in 'microgravity' could result in better high-performance bio-medical and transport components
‘Why do we go to space?” Italian astronaut Paolo Nespoli posed the question to an audience in Dublin earlier this month as part of Science Week. The answers tumbled in: to explore, to learn, because it’s cool.
There are other, tangible benefits, too, according to Nespoli, describing how technologies developed for space applications have also helped to improve the efficiency of transport here on Earth.
Space offers a unique environment of microgravity or “weightlessness”. Yes, that means sometimes your spoon floats off as you are trying to eat dinner, notes Nespoli, who spent six months aboard the International Space Station. But it also means you can carry out experiments in a lack of gravity, and this can help to find out more about the effect gravity has on materials such as metals, and on our bodies on Earth.
Research in space and on the ground is now looking to get a better handle on those effects and how to overcome them. And the findings could lead to spin-off benefits such as lighter metals and plastics and maybe even better health as we age.
So what’s the connection between gravity research and metal alloys in your car, or an implant in your knee? Gravity can affect the microscopic structure of the alloys as they solidify into shape, and that in turn affects how they perform, explains Dr David Browne, a senior lecturer at the school of mechanical and materials engineering in University College Dublin. “Metal is melted and poured into a mould, then it solidifies. And the progress of solidification essentially defines the grain structure in the casting,” he says.
“There is a push from industry to get a better handle on what is going on during alloy solidification so we can potentially control it better. The net effect could be lower-cost, lighter-weight components for transport applications primarily, and also increasingly high-performance components for biomedical applications.”
The issue is that on Earth the process of solidification is quite complicated to analyse, because as the molten alloy is solidifying, the liquid metal moves due to gravity, explains Dr Browne. He’s involved in an international study called CETSOL, which has been comparing how alloys solidify on Earth and in microgravity on the International Space Station.
“The alloys melt at over 600 degrees centigrade so they have to be encapsulated within ceramic crucibles. We don’t want them escaping and floating around,” he says. “And the astronauts switch them on before they go to bed because these very delicate experiments require that the astronauts not be moving around.”
The alloys solidify within a few hours, and when they come back to Earth the researchers chop them up and analyse their structure under the microscope.
“By removing the liquid motion, the process is much simpler and easier to understand,” says Dr Browne.
Researchers at UCD have already built a computer model of the process and one of the next steps will be to X-ray the alloys as they solidify in order to get a more dynamic picture of what is happening. UCD is leading a project to X-ray solidifying alloys aboard a “sounding rocket”, according to Dr Browne.
“The rocket goes about 250km straight up, and once it exits the atmosphere the engines are cut, then it goes into freefall for about five to 10 minutes to create an environment of microgravity,” he says.
But there is a way to go yet before those precious few experimental moments: “The rocket is planned for early 2015 – it’s a long process.”
Already, technology to help make rockets lighter has been having an effect on more everyday items, such as civilian aircraft and even wind turbines.
Reducing the mass of rockets can dial back enormously on expense, saving as much as €25,000 for every kilo lost, explains Dr Conchúr Ó Brádaigh, a senior lecturer in mechanical and biomedical engineering at NUI Galway.
He is also RD director with ÉireComposites Teo, which is working with the European Space Agency on technologies to help replace metal structures on rocket launchers with light but strong “composite” plastic materials.
Éirecomposites has been applying the fruits of the rocket-related research to manufacture parts that remain closer to Earth, such as components of wind turbines and passenger aircraft.
“The next time you are taking an Aer Lingus A320 flight in Europe, have a look at the engine as you are going up on the plane,” says Dr Ó Brádaigh. “It’s quite likely some of the parts are manufactured in Galway.”
Confined to bed - for science
In the “weightlessness” of space, strange things happen to the human body over time: fluids shift around, muscles waste away, bones become weaker, and you see metabolic effects and changes in how the body accumulates fat.
Studies are tracking what happens to astronauts when they are orbiting in conditions of microgravity or weightlessness. But it’s an expensive process to put people up there.
So on Earth, experiments are looking to recreate a lack of gravity by recruiting people on to bedrest studies. On paper it might sound like a sweet deal, but the reality is that volunteers can be confined to bed for weeks at a head-down tilt of six degrees, explains Dr Donal O’Gorman, who directs the centre for preventive medicine at Dublin City University.
Why simulate a lack of gravity on the human body? “It provides a very interesting and reversible model for what is almost like an accelerated rate of ageing,” says Dr O’Gorman.
He and PhD student Helena Kenny are working on an international study to collect and analyse data from 12 volunteers taking part in a three-week bedrest study in France.
Supported by Enterprise Ireland through ESA’s Prodex programme, they are looking at whether the lack-of-gravity model can affect how the body uses energy, what happens to the composition of muscles, and whether interventions such as physical vibration or food supplements could affect the outcome.
O’Gorman says the hope is that the findings will help to shed light on the early physiological changes of ageing and some chronic medical conditions.