January 18, 2005

Nanotech on Titan

Titan.jpg

One of the things that the early nanotech boosters used to trumpet, besides trivial applications like regrowing limbs and downloading consciousness, was the colonisation of space and the terraforming of planets. No wonder most sane investors gave nanotechnology a wide berth for a long while.

Nanotechnology actually has some use in space applications, and ‘tools for nanotech’ company FEI had a part to play in the recent successful landing of the Huygens probe on Titan, some 750 million miles away. Some readers will remember that Cientifica started life as a spin out from the European Space Agency in 1997, and in the early 90’s when Huygens was being put together, Tim Harper spent most of his time looking for failures in the electronic components that went into the probe using a variety of AFMs, FIBs, and electron microscopes.

It is worth remembering, that on a 7 year, 750 million mile voyage, it only takes one failure to disable the entire probe. Of course the way of hedging against this is to make sure that the components used are up to the job. While there has been a swing to ‘off the shelf’ companies in recent years, much of what went into Huygens was exhaustively tested to make sure that it would survive the journey. Testing ranged from exposing components to the sort of environment they would meet in space, from radiation to extremes of temperature, to simply measuring the various internal layers to make sire that what was delivered was indeed what was specified for the job.

It was around the time that the components for Huygens were beginning to be evaluated that the European Space Agency bought its first Focussed Ion Beam Milling system (FIB), which was in fact only the second instrument of its type to be delivered in Europe. Until this point, the localisation of a failure in a component was a two day process. First the failure site, which may be due to a particle in the wrong place, a deviation from tolerances in a layer of material or a whole host of other defects had to be located. The component then had to be potted in resin, and overnight job, before being sawn in half, ground and finally polished to expose the site of interest. Of course during the final polishing stage the phone may ring, or the technician doing the polishing may be a little heavy handed and the whole process would have to be repeated (providing of course that there was a second example of the failure).

The arrival of the FIB changed all of that. Suddenly locating a failure became as simple as loading a sample, digging a hole with an ion beam to expose the areas of interest, polishing the face with a much finer beam, then either imaging in the FIB, or in those days more likely, transferring the sample to an electron microscope for analysis and measurement of the defect.

So, while many may trumpet the future possibilities of nanotechnology in planetary exploration, the fact that we managed to get to Titan was partly as a result of the application of ‘tools for nanotech’ thirteen years ago. Since Tim’s initial purchase, various FIB instruments have been helping ESA speed up the process of component evaluation and failure analysis. While Huygens did suffer one failure, the loss of one of the data channlels, this was due to a software error rather than a hardware failure.

Posted by Cientifica at January 18, 2005 09:54 AM | TrackBack
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