Spacecraft mission to intercept a new comet

The European Space Agency (ESA) has just announced that its latest mission, called Comet Interceptor, will visit a comet from the very edge of our Solar System. The international team on this mission is led by researchers from University College London and the University of Edinburgh's School of Physics & Astronomy.

Exploration of comets

ESA has a long history of exploring comets, beginning with their Giotto mission to comet Halley in the 1980s, and most recently with the ground-breaking Rosetta mission, which was the first spacecraft to land on a comet in 2014.

It is hoped that the Comet Interceptor mission will enable scientists to get, for the first time, a glimpse of a pristine fragment left over from the formation of our Solar System before the heat of the Sun erodes its surface. The comet may possibly even be a visiting comet from another star entirely.

Comet flyby

To visit a 'new' comet coming into the inner Solar System, the mission has to do something very unconventional in space exploration – the spacecraft has to be designed and launched before its target is discovered. This makes a comet flyby, already a challenging manoeuvre, an even more difficult mission.

Comet Interceptor does this by hitching a ride into space with the Ariel space telescope, which ESA selected last year to study the atmospheres of planets orbiting around distant stars. This telescope will go to a Lagrange point - a place in space where the gravitational pull of the Earth and the Sun balance to produce a stable parking location. In the meantime, astronomers on Earth will make use of the powerful new Large Synoptic Survey Telescope (LSST), currently under construction in Chile, to scan the sky for an incoming comet in the right orbit. When it is found, ESA will calculate a trajectory for the spacecraft to intercept it, and Comet Interceptor will fly past the comet at high speed, returning images and measurements of the comet’s composition to Earth.

Collection of data

Comet Interceptor is actually three spacecraft in one – as it approaches the comet it will release two smaller probes. These small probes will make a daring close approach to the comet’s icy nucleus, braving a high speed encounter with the dust and gas spewing from the comet, which at the likely speeds involved (up to 80 kilometers per second) is like flying through a hail of bullets. The probes will send back data to the main spacecraft at a safer distance, which will relay the results back to scientists on Earth, along with the measurements made by its own long range instruments. The main spacecraft and one of the smaller probes will be provided by ESA, with the Japanese space agency JAXA providing the other small probe, reusing some of the technology they are using in their current asteroid mission, Hayabusa 2. 

International collaboration

This mission is led by scientists from University College London, Dr Colin Snodgrass from the School of Physics and Astronomy and an international team from Europe, Japan and the USA. 

Dr Snodgrass recently joined the University as part of the ‘City Region Deal’ investment in Data Driven Innovation and is based at the Institute for Astronomy (IfA) at the Royal Observatory Edinburgh.

The announcement of this mission is incredibly exciting, and comes at just the right time as we seek to establish a new research group in comet science in Edinburgh. The mission will be a focus for these activities, which will also provide opportunities to collaborate with other researchers in space-related areas across the university, and with the booming local space industry around the city and across Scotland.

Dr Colin Snodgrass

The IfA is already leading UK contributions to the Large Synoptic Survey Telescope (LSST), which will be necessary to discover an approaching comet with enough warning time for the mission to reach it.

Related links

Comet Interceptor

School of Physics & Astronomy

Institute for Astronomy

Dr Colin Snodgrass' staff profile

European Space Agency