A new European Space Agency science mission, proposed by the UK,
to 3D-map a comet for the first time has reached a major
milestone.
The Comet Interceptor mission was formally adopted by the
European Space Agency (ESA) at a meeting in Madrid today
(Wednesday, 8 June 2022), moving from the design phase to
implementation, with the next step to select a contractor to
build the spacecraft and a robotic probe.
Due for launch in 2029, it will see one main spacecraft and two
robotic probes – the other built by the Japanese Space Agency
(JAXA) – travel to an as-yet unidentified comet and map it in
three dimensions.
Caroline Harper, Head of Space Science at the UK Space Agency,
said:
This is a huge milestone for the Comet Interceptor mission. After
an intensive period working on the mission design feasibility and
definition, we are ready to move forward to the full
implementation stage.
Comet Interceptor will not only further our understanding of the
evolution of comets but help unlock the mysteries of the
Universe.
The mission was first proposed by an international team led by
University College London’s Mullard Space Science Laboratory
(MSSL) in Surrey and the University of Edinburgh.
Professor Geraint Jones, from the UCL Mullard Space Science
Laboratory, said:
We should get our first glimpse of a truly pristine body with
this mission – an invaluable example of the objects that came
together to form the Earth and other planets. The comet’s surface
will be largely unchanged since the time of the Solar System’s
formation several billion years ago, and I can’t wait to see that
uncharted territory sometime in the 2030s.
It’s fantastic to get the green light for the mission after
almost four years of hard work since the European Space Agency’s
invitation to propose came out. The international team of
scientists and engineers, working with colleagues at ESA, kept
mission development on track despite the many complications
raised by Covid-19.
Professor Colin Snodgrass, from the University of Edinburgh,
added:
It is very exciting to be part of a mission that follows a
completely new approach: designing and building the spacecraft
before the target is even discovered. This opens up opportunities
to visit space objects that were completely inaccessible before,
such as comets entering the inner solar system for the very first
time, or possibly even interstellar objects that formed around a
distant star.
The UK Space Agency has so far provided £2.3 million in funding
for two instruments on the mission: The Modular InfraRed
Molecules and Ices Sensor (MIRMIS) instrument is led by the
University of Oxford. MIRMIS will deliver a unique dataset,
providing information such as the comet’s shape, size and
rotation state. The Fluxgate Magnetometer (FGM) sensor led by
Imperial College London will provide high accuracy and high-time
resolution measurements of the comet’s magnetic field size and
direction.
Professor Neil Bowles, University of Oxford, said:
Working with our colleagues in Finland, MIRMIS will observe Comet
Interceptor’s nucleus at infrared wavelengths that are
particularly sensitive to temperature and the composition,
mapping out the material in the nucleus on what is possibly the
object’s first close encounter with the Sun. Combined with the
data from Comet Interceptor’s other instruments and probes, this
will provide a unique snapshot of a potentially very ancient
object.
By exploring comets, we learn about the origins of our Solar
System.
Comets are what is left over when a planetary system forms and in
each ancient object is preserved information about the formation
of the Solar System 4.6 billion years ago.
Comet Interceptor would be the first mission to travel to a comet
which has never previously encountered the inner Solar System.
To do this, it will need to launch and reach a holding position
around one million miles away from Earth. There it will lie in
wait – possibly for years - until astronomers on the ground spot
a suitable comet for it to intercept. The two probes will make
closer passes of the comet’s nucleus and beam their data back to
the main craft.
This new ambush tactic is the first of its kind. The fly-by of
the three spacecraft, including the two probes, which measure
less than a meter across, is likely to take just a few hours but
could illuminate conditions that prevailed more than 4 billion
years ago.
Previous missions have studied comets trapped in short-period
orbits around the Sun, meaning they have been significantly
altered by our star’s light and heat. Breaking from that mould,
Comet Interceptor will target a pristine comet on its first
approach to the Sun.
The scientists are likely to target a comet travelling from the
Oort Cloud — a band of icy debris that lies about halfway between
the Sun and the next nearest star.
This debris was formed during the conception of the Solar System
but was rapidly ejected to its outermost edge. Unlike more
familiar comets, their surface will not have been vaporised by
the Sun’s energy — a process that leads to dust building up on a
comet, obscuring its original state.
Once the probes reach a pristine comet, they will study and
scrutinise the chemical composition of it, with one aim being to
evaluate whether similar objects may have brought water to planet
Earth in the past.
