Internet traffic jams may become history if ESA succeeds in developing the technology to see nearby Earth-sized planets. Why? Looking at new ways to detect planets, instead of bulky mirrors and lenses in space, ESA is thinking of building miniaturised optical systems that fit onto a microchip. Such ‘integrated optics’ would also allow Earthly computer networks to use high-speed routing of data streams.

Data moving around the Internet are a bit like cars travelling around Europe. As you drive down roads, you can drive fast. However, when you have to change direction at a junction, you have to slow down a lot. The same thing happens on information highways. Beams of light carry data along fibre-optic cables at very high speeds. When the data arrive at computers, known as servers, the servers redirect the data to their final destinations. Presently, you need to convert the light signals into electricity, and that slows everything down.

Electrons move at a speed of a few kilometres per second through a circuit, whereas light travels at nearly 300 000 kilometres per second. Integrated optics would leave the data as light and simply channel it through the chip, in the right direction. Scientists call this area integrated optics because of the integrated circuit board on which chips are mounted. Instead of miniaturised electronics, however, miniaturised optics are placed on a microchip.

ESA has a strategy to enable more sophisticated searches for extra-solar planets in the future. Two planned developments rely on combining the light from a number of different telescopes. Both could greatly benefit from this technology. They are ESA’s Darwin mission and its Earth-bound precursor, the ESA/ESO Ground-based European Nulling Interferometer Experiment (GENIE).

When you combine light beams, traditionally, you need moving mirrors and lenses to divert the light beams to where you want them. However, if the system moves, it can break. As Malcolm Fridlund, Project Scientist for Darwin and GENIE says, “To change to integrated optics, which is much smaller and has no moving parts, would be highly desirable.”

This is certainly desirable, but also difficult. At present, integrated optics is a science that is far behind integrated circuit technology. For this reason, ESA are funding two studies. For example, Astrium has been asked to take a traditional optics approach and Alcatel is investigating an integrated-optics solution. “We will take the decision on whether GENIE will use integrated optics in just over one year,” says Fridlund.

In the future, Darwin, ESA’s ambitious mission to find Earth-like planets, may also use integrated optics but using longer wavelengths of light than GENIE. This is uncharted ground as far as integrated optics is concerned. However, Fridlund is currently reviewing proposals from industrial companies who would like to take up the challenge. “What I’m reading in those proposals is making me highly optimistic,” says Fridlund, “I don’t know whether mid-infrared integrated optics will have any commercial application yet, but until we develop them, we’ll never know.”

Should the integrated-optics approach work, the rewards would go far beyond a few improvements in searching for planets. Here on Earth, for all home-computer users, for example, it could speed up the Internet by 100-1000 times. The consequences of surfing the Web at such speeds would be amazing.

Note to editors

Darwin Darwin is a flotilla of eight spacecraft that will find Earth-like planets and analyse their atmospheres for the chemical signature of life. Six spacecraft will be space telescopes. The seventh spacecraft will combine the light from these to simulate a mirror much larger than the one of a single telescope and the last spacecraft will communicate with Earth and the flotilla. The mission is being studied at present and is expected to launch sometime after 2014.

Genie GENIE (Ground-based European Nulling Interferometer Experiment) is an ESA/ESO instrument to perform nulling interferometry using ESO’s Very Large Telescope (VLT), a collection of four 8-metre telescopes in Chile. Once up and running, GENIE will provide a training ground for astronomers who will later use Darwin. One of GENIE’s major tasks will be to develop the target list of stars for Darwin to study. GENIE will see failed stars, known as brown dwarfs and, if the instrument performs to expectations, may also see some of the already-discovered giant planets. So far, these worlds have never been seen, only inferred to exist by the effect they have on their parent stars. GENIE is expected to be on-line by 2006.

For more information, please contact:

ESA Communication Department
Media Relations Office
Paris, France
Tel: 33 (0)1 5369 7155
Fax: 33 (0)1 5369 7690

Malcolm Fridlund
ESA – Darwin & GENIE Project Scientist
ESTEC, The Netherlands
Tel: 31 (0)71 565 4768
E-mail: malcolm.fridlund@esa.int

Andres Karlsson
ESA – Darwin Project Manager
ESTEC, The Netherlands
Tel: 31 (0)71 565 3532
E-mail: anders.karlsson@esa.int