On the hunt for alien life: NASA’s planet-hunting TESS satellite begins its mission

Victoria Woollaston April 16, 2018

After a failed launch attempt on Monday, NASA’s planet-hunting TESS satellite has finally been flung into orbit onboard a SpaceX Falcon 9 rocket.

On the hunt for alien life: NASA's planet-hunting TESS satellite begins its mission

The mission, which will spend the next two years surveying the sky for planets outside our solar system, was due to take off from Cape Canaveral, Florida on 16 April at 18:32 EDT (23:32 BST). However, a tweet from SpaceX’s official Twitter handle said engineers were “standing down to conduct additional GNC analysis”. There were also reports NASA wanted to make further tests to the satellite itself before launch.

Thankfully, the second attempt was successful. NASA’s Transiting Exoplanet Survey Satellite was sent to space on 18 April from the Space Launch Complex 40 at Cape Canaveral Air Force Station in Florida at 18:51 EDT (23:51 BST).

“Liftoff of the SpaceX Falcon 9 rocket carrying TESS, a planet-hunting spacecraft that will search for new worlds beyond our solar system,” NASA Launch Commentator Josh Finch said. “We are thrilled TESS is on its way to help us discover worlds we have yet to imagine, worlds that could possibly be habitable, or harbor life,” added Thomas Zurbuchen, associate administrator of NASA’s Science Mission Directorate in Washington.

TESS is an acronym for the Transiting Exoplanet Survey Satellite and the mission is set to catalogue thousands of planets outside of our solar system, known as exoplanets. The main objective will be to find the so-called Earth 2.0 – an exoplanet capable of supporting life.

What is the Transiting Exoplanet Survey Satellite?

Over the next two years, TESS will survey the sky, breaking it into 26 sections, each 24 degrees by 96 degrees across, specficially looking for exoplanets that periodically block part of the light from their host stars. These events are called transits, hence TESS’ name. Powerful cameras on TESS will monitor each section for at least 27 days at a time, looking at the brightest stars.

The reason astronomers use the transit method when searching for exoplanets is because it looks for dips in the visible light of stars. This suggests a planet has crossed in front of the star, along our line of sight. If these dips repeat periodicially, it suggests there is a planet, or planets, orbiting a star. This is how the planets in the TRAPPIST-1 system were spotted.

Depending on how much light there is, NASA can determine the size of the star as well as its planet(s) and the length of orbits. All of these elements can give an indication of the planet’s proximity to the star, which in turn can help experts determine the conditions on that planet and the chance of it supporting life.

After the TESS launch has compiled a list of candidate exoplanets, ground-based surveys, using telescopes here on Earth, will use this data to look at each planet’s composition to see if they’re rocky, like Earth, or gas giants like Jupiter. TESS could even find exoplanets of a kind we’ve never seen before.

During its mission, TESS will study and document 200,000 of the brightest stars near the sun to search for any transiting exoplanets. Of these, some 300 are expected to be Earth-sized and super-Earth-sized exoplanets, which are worlds no larger than twice the size of Earth.

The stars being studied by TESS are between 30 to 100 times brighter than those surveyed by the Kepler and K2 missions and TESS will cover a sky area 400 times larger than that monitored by Kepler.

Today’s date is the earliest the TESS launch can happen, but if the weather isn’t optimal, the mission launch window will run until June 2018.