UCL researchers are investigating how a UK-led team could design and build one of the core instruments on a flagship NASA mission, the Habitable Worlds Observatory, which will search for signs of life on distant planets.
The mission is expected to launch in the early 2040s and is currently in an early preparatory phase. It will be "the first specifically engineered to identify habitable, Earth-like planets… and examine them for evidence of life", according to NASA.
A consortium led by UCL scientists, funded by the UK Space Agency, are developing a proposal for a high-resolution imager that could be designed and built by a UK-led team. The imager would be used to measure the planets' masses, which is key to interpreting their atmospheric features and whether or not they have life.
Dr Vincent Van Eylen (Mullard Space Science Laboratory at UCL), consortium lead, said: "The planets we have discovered so far are not places that could realistically have life. That is because our current techniques are good at finding planets that are very hot, orbiting close to their host star - inhospitable places that are nothing like Earth.
"The Habitable Worlds Observatory would use an instrument called a coronagraph to block the bright glare of a host star. This would allow us, for the first time, to see distant planets directly, including small, rocky planets that are similar to Earth. Using the coronagraph, we can then directly study which molecules may be present in their atmospheres, such as water, oxygen, or methane, and infer whether the planet has life.
"Our instrument, the high-resolution imager, would allow for estimates of these planets' masses by precisely measuring the movements of their host stars and inferring the gravitational tug of the planets from wobbles in these movements."
Co-investigator Professor Alan Smith (Mullard Space Science Laboratory at UCL) said: "The high-resolution imager is conceived as having a relatively wide field of view and capturing light from the infrared to the ultraviolet. As well as helping us to understand habitable planets, it would be a general-purpose instrument, producing beautiful images and giving us insights into many of the current questions in astrophysics."
The UCL-led consortium includes scientists and engineers from Durham University, the University of Portsmouth, RAL Space (the UK's national space laboratory), and the UK Astronomy Technology Centre.
This consortium is one of two groups funded by the UK Space Agency to investigate the feasibility of a UK-led high-resolution imager, with the other group led by the University of Leicester.
Dr Caroline Harper, Head of Space Science, UK Space Agency said: "The Habitable Worlds Observatory is one of the most ambitious scientific endeavours of our time. It is the first mission that will be designed specifically to answer the profound question of whether we are alone in the universe.
"The UK is interested in leading an instrument for HWO, and a high-resolution imager is one possibility for this, building on our world-class expertise in space instrumentation and exoplanet science. We are proud to support UCL and its partners as they explore this exciting opportunity to help NASA search for life on Earth-like worlds."
In addition to the US-led coronagraph and the high-resolution imager proposed in this study, the observatory will include a multi-object spectrograph and potentially another instrument not yet decided.
Most of the 6,000 or so confirmed exoplanets (planets outside our solar system) we know about were discovered by looking at the light from their host star - for instance, by measuring the dip in brightness that occurs when a planet passes in front of its star. This technique works well for planets close to their host star. But it misses smaller planets and those orbiting above or below their star's plane.
Exoplanets have been imaged directly only in rare cases. These include large and bright Jupiter-sized planets far from their star.
The UCL-led consortium builds on expertise drawn from leading roles on European Space Agency missions such as Euclid (where a UCL-led team designed and built the main camera, one of the largest ever launched into space), and Plato, a planet finding mission due to launch next year.
