Meet CHEOPS (Pronounced KAY-ops), your friendly neighborhood exoplanet investigator aka the spacecraft looking for planets that could harbor life.

Man has long gazed at the stars in the universe above, hoping to uncover its mysteries. Over the centuries, there have been theories proposed to explain exactly how the universe works and questions about life on other planets. 

Thanks to ever-advancing technology, we are getting closer to answering our questions with more refined approaches. Technical innovations like spacecraft and satellites have improved our vision of space tremendously, and with it, our knowledge of how the cosmos works.

One of these technological innovations is the CHEOPS space telescope or the CHaracterising ExOPlanet Satellite (pronounced KAY-ops) built and led by the European Space Agency (ESA).

What is CHEOPS?

CHEOPS is the first mission designed to investigate exoplanets we’ve discovered.

Why is this important?

Well, we know from past observations and calculations that there are as many planets in our galaxy as there are stars. We’ve detected 4,000. 

Is our Earth unique among this crowd? Or could there possibly be other planets that can harbor life?

Do other planetary systems or solar systems like ours exist or is ours one of a kind?

These are questions that have puzzled us for centuries and finding the answers requires us to go beyond merely detecting new planets and recording their existences.

CHEOPS is following up on exoplanet discoveries and seeking to characterize them. The first facts it’s searching for are the exoplanets’ diameters and masses. This info will allow scientists to calculate a planet’s density, which in turn tells them whether its mass is rocky like the Earth’s, mostly gaseous like Jupiter’s, or somewhere in between like Neptune’s.

How does CHEOPS work?

CHEOPS was successfully launched on December 18, 2019, and positioned approximately along the terminator of the Earth where day transitions into night.

Researchers equipped the satellite with a single science instrument: a specialized camera called a photometer to capture starlight.

Starlight reaches the photometer through a 32-centimeter-wide telescope pointing away from the sun for observation and equipped with a sun shield to maintain coolness. 

CHEOPS observes the movement of exoplanets. It’s also capable of calculating its diameters within 10% of accuracy. That data, combined with mass estimates arrived at using other exoplanet-tracking techniques like radial velocity, can reveal many of the characteristics of these planets.

The most common size of an exoplanet is between the sizes of Earth and Neptune – there are super-Earths and sub-Neptunes. The goal is to figure out if these exoplanets can host people. 

If CHEOPS identifies planets capable of hosting life, researchers will follow up by researching their atmospheres using space- and ground-based telescopes.

How does CHEOPS measure an exoplanet’s diameter and mass?

Exoplanets in space


Similar to its predecessors, Kepler and TESS, CHEOPS measures the size of exoplanets with the transit method. 

It consists of watching for dips in the light from other stars as exoplanets pass before them.

However, unlike Kepler and TESS, CHEOPS is focused solely on studying exoplanets that have already been discovered.

How big is CHEOPS?

Is it massive?

Is it like the International Space Station, given that it’s a multi-national effort supplying information to space research agencies all over the planet?

None exactly. 

CHEOPS is actually about the size of a golf cart. It measures 1.5 meters high and has a hexagonal footprint that is 1.6 meters across. When including its propellant, it has a mass of 280 kilograms.

 Bigger isn’t always better. 

Who owns the CHEOPS Space Telescope?

A view of Earth from the moon


CHEOPS is jointly owned by the European Space Agency (ESA) and Switzerland, under the leadership of the University of Bern, in collaboration with the University of Geneva.

It’s gone through extensive testing, the end of which happened during the start of the COVID-19 pandemic. On Wednesday, March 25, 2020, the satellite was deemed ready for science and was handed over to be operated by a group of scientists and engineers from approximately 30 institutions in 11 European countries.

Would you live on another planet?

So, do you believe that there’s life out there beyond Earth? Would you like to live on an exoplanet if it was found to be hospitable for life? Comment your thoughts below and don’t forget to share this post with those you know would be interested!

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