Finding other forms of life in the Universe means first finding planets on which they might be sitting.

Planets aren't easy to spot because they don't generate light like suns and, even if they reflect a lot of sunlight, their sun would still outshine them.

Fortunately, there are a couple of tricks astronomers use to get around this. One involves looking for the influence the planet's gravitational pull has on the sun it's orbiting. If a planet is big enough and close enough, it will 'tug' on the sun making it look like it's wobbling.

To spot this stellar shimmy, astronomers have to know exactly where a star is in relation to other stars. NASA's Space Interferometer Mission (SIM) PlanetQuest, launching in 2011, will pin-point stars using telescopes mounted on each end of a 10 metre long scaffold.

Problem is, a star dozens of light years away won't look like it's wobbling much, so the position of the stars has to be measured very precisely. To do this, astronomers need to know the distance between the telescopes to within a tenth of a nanometre (the distance changes a little bit when the spacecraft manoeuvres). Now, a nanometre is a millionth of a millimetre, and a tenth of that translates to less than the width of a hydrogen atom.

Lasers are used to measure the distance between the telescopes - and that's where an Australian piece of precision scientific equipment is used. Called a cube corner, it's a kind of retroreflector (as are cats eye lane markers on the road).

Unlike mirrors, which have to be perfectly aligned before a laser will bounce truly, it doesn't matter from which direction a laser - or any light for that matter - enters a cube corner, it bounces straight back from whence it came. That is, it will if the cube corner is built properly.

CSIRO Industrial Physics (CIP) is the only place on Earth that can make cube corners to the level of precision demanded by NASA. The right angles of their cube corners are accurate to within one tenthousandth of a degree, and the wedges, which have to come together at exactly the right spot, are off-target by less than five thousandths of a millimetre.

Dr Ben Platt comes to collect the first double cube corner from Dr Bob Oreb in the optics workshop at CSIRO Industrial Physics.

Dr Ben Platt, from NASA's Jet Propulsion Laboratory (JPL) said: "We've had cube corners made by other organisations around the globe, but CSIRO's was the only one that met the stringent requirements necessary for us to meet a critical milestone of SIM."

The team in the optics workshop at CIP make cube corners by fabricating ultra-smooth discs and wedges of Zerodur, a glass-like substance similar to ceramic hot plates. Once the pieces are really, really clean, the team bring them together in a process called optical contacting. There's no glue involved, it knits together molecule by molecule.

It takes many weeks to get the pieces of Zerodur ready for assembly. The team line them up using special microscopes, a laser-based system, a device which lets them move the pieces by just nanometres, and computerised imaging technology that they designed themselves. Once the pieces are touching, the team has ten minutes before the bond sets.

A double cube corner has already been put through its paces in JPL's simulator. Recently, four members of the CSIRO team went over to discuss the results. Team leader, Dr Bob Oreb, said: "Our cube corners met JPL's performance target by a large margin and five days ahead of their demanding time schedule. Everyone we met was ecstatic and regarded these results as a huge success.

"We are now discussing future work with JPL including triple cube corners and the next stage of SIM - engineering and flight."