Developing New Materials With Space Science

Scientists at the European Space Agency are using techniques inspired by their experience with outer space to make new and better products here on Earth. Certain compounds and alloys which are not normally viable can be made in different ways once forces such as gravity are removed from the equation. From BBC News: "The near absence of gravity (microgravity) has a profound influence on the way molten metals come together to form intermetallics and 'standard' alloys. With no 'up' and 'down' in the space environment, a melt doesn't rise and sink as it would at the planet's surface and that means solidification can turn out very differently. 'Gravity induces a lot of segregation of the elements,' explains IMPRESS scientist Dr Guillaume Reinhart. 'For instance, tantalum and niobium are heavy atoms and in doing the solidification process on the ground, they will segregate in different places and produce a very heterogeneous material. If you do this in microgravity, you obtain a very homogenous material because you prevent separation; and you have a much more efficient material, mechanically.'"

Comments

Re:Why use space?

[Anonymous Coward]

Ignoring the deceleration problem at the bottom, with a 5 km shaft (which is not cheap to make) you only get 30 seconds of free fall to work with. And that's in a vacuum! In any shaft on earth, you are going to have air, which means you will hit terminal velocity at some point, which will ruin the effect.

This duration of free fall is comparable to the Vomit Comet, which can produce brief periods of free fall without the ugly smashing part at the bottom of a mine shaft. :)

NASA used to talk about this

[Animats]

Back when the Shuttle was called the "National Space Transportation System" and NASA was claiming that launch costs would come down, NASA used to talk about materials processing in space. That was a long time ago.

The trouble with materials processing in space is that for small things, gravity is dominated by surface tension and other forces like Brownian motion. So biological processing in space never amounted to much. Some early Shuttle flights carried an electrophoresis apparatus designed for zero-G operation to make some kind of diabetes drug. But bioengineering went beyond that approach; today it's easier to engineer some bacterium to crank out whatever you need.

For big objects, there would be some advantages (and many disadvantages) to working in zero G. Handling molten metal in zero G safely would be tough. One molten droplet could puncture anything we currently send into space. With gravity and in air, molten droplets don't travel very far and cool. In space, they can go a long way. Steel mills use floors of dirt or refractory brick in molten metal areas; concrete will blow up when its water content boils. Welding in space has been tried, but on a very small scale, and very nervously.

Lift to orbit is far too expensive to justify flying heavy metal up there for casting and welding. This is one of those ideas that won't be feasible unless and until lift to orbit costs about what long distance air travel costs now.