A new microsatellite named Twinkle is to be launched into near-Earth orbit, from where it will study the atmospheres of at least 100 exoplanets within the Milky Way.

A joint venture between University College London (UCL) and Guildford-based space tech firm Surrey Satellite Technology Limited (SSTL), the satellite will be launched within the next four years, according to a presentation made to the Royal Astronomical Society today.

"Twinkle is a very ambitious mission," said lead scientist, Prof Giovanna Tinetti of UCL.

"Nearly two thousand exoplanets have been discovered to date, but we know very little about these alien worlds.

We can measure their mass, density and distance from their star.

From that, we can deduce that that some are freezing cold, some are so hot that they have molten surfaces, some are vast balls of gas, like Jupiter, or small and rocky, like Earth.

But beyond that, we just don’t know. Twinkle will be the first mission dedicated to analysing exoplanets' atmospheres, and will give us a completely new picture of what these worlds are really like."

Twinkle will provide more information on exoplanetary atmospheres by analysing the spectral 'fingerprint' of starlight that has passed through them.

Twinkle mission scientists will use techniques pioneered by Tinetti herself for the analysis of data returned by the Hubble and Spitzer space telescopes, which should reveal, among other things, whether the atmospheres contain water vapour - a sign of a planet's suitability for hosting life - and/or methane - an indicator that life may already be present.

For exoplanets that orbit larger/brighter stars (and for which more starlight data is therefore available), Twinkle will also be able to produce maps of clouds and temperatures.

Understanding the composition of an exoplanet's atmosphere can also tell us more about the planet's history - revealing, for instance, if it was formed in its current orbit, or has migrated from closer to or further away from its parent star.

This in turn can help scientists build up a more accurate and comprehensive picture of mechanisms for planetary and solar system formation.

The mission will cost a total of around £50 million, which will come from a mixture of private and public funding sources.

"The UK has already made an outstanding contribution to exoplanet detection with the WASP survey programme. Twinkle is a unique chance for the UK to build on this and take the world lead in understanding exoplanet science," said Prof Jonathan Tennyson, senior advisor for the Twinkle mission.

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To find out more, visit the official Twinkle website.


Elizabeth Pearson
Ezzy PearsonScience journalist

Ezzy Pearson is the Features Editor of BBC Sky at Night Magazine. Her first book about the history of robotic planetary landers is out now from The History Press.