Last updated April 18, 2018 at 3:09 pm
The newest exoplanet hunter is on the pad and ready for launch.
NASA’s newest exoplanet hunting satellite telescope is scheduled to launch later today from the Cape Canaveral in Florida.
The telescope, known as the Transiting Exoplanet Survey Satellite, or TESS, will be looking for planets outside of our Solar System, helping scientists discover what these planets are made of, and potentially whether any of them might be able to support life.
Its launch comes as its predecessor, the Kepler Space Telescope, winds down. Kepler is running out of fuel, meaning over the next few months it will lose its ability to manoeuvre and point its antenna back towards Earth.
However, TESS won’t be directly taking over from Kepler. Whereas Kepler was tasked with identifying as many exoplanets as possible, TESS will instead be narrowing its focus to the stars closest to Earth.
“The Kepler space telescope found an astounding number of exoplanets, but most of them are many, many light-years away, too dim for us to learn much about them. That’s why TESS is so important: it will find exoplanets around stars in our cosmic backyard,” said Lisa Kaltenegger from the TESS science team.
“TESS will provide a list of our top neighbouring worlds for any follow up observations, as well as any far future travel plans.”
A key part of this mission will be to investigate each candidate planet, finding out more about what it is made of, and conditions on the planet, than Kepler ever could.
Taking a wider view
Unlike Kepler which only searched a region of the galaxy, TESS will image over 85% of the sky over the next two years – around 350 times the area searched by Kepler. It’s expected to monitor at least 200,000 stars.
“TESS is small but it is mighty, because it will search the whole sky, all the bright stars we can see at night, for worlds orbiting them. When looking up at night, we will be able to point at bright stars in the night sky and say — right there, there is a star that hosts another Venus, Mars, or maybe even another Earth,” said Kaltenegger.
TESS will be searching for planets using the same technique used by Kepler. As planets pass in front of their stars, they cause a small drop in the amount of light which astronomers call a transit. This slight dimming of light can be detected by orbiting observatories such as Kepler and TESS. However, TESS will be focussing on stars much closer than Kepler did, only 30-300 light years away. This means the stars will be far brighter in the sky than more distant stars – around 30-100 times more luminous, making it easier to discover and characterise the planets.
Following discovery by TESS, ground and space telescopes will focus in on candidates and reveal more details about the planets. In particular, the scientists will be curious about planets which could be rocky like Earth, their atmospheres, and whether they could support any life.
One-way astronomers can tell whether a planet is rocky is by measuring its density. More dense planets have greater gravitational forces, which even though small, still exert influence on their star. By analysing the amount of ‘wobble’ of the star caused by the planet’s movement, astronomers can calculate the mass of the planet.
The brighter stars will allow this calculation to be made quicker and more accurately than with the Kepler data.
TESS is slated as a two-year initial mission, with extensions possible should scientific reasons stack up. However, initially it was meant to be work in conjunction with the James Webb Space Telescope, the launch of which has been delayed to at least 2020. The JWST was intended to be a powerful tool probing the atmospheres of targets identified by TESS. This delay to JWST may see TESS’s life be extended.
Scientists and engineers are already planning for ways to extend TESS’s mission.
A dream discovery would be to find an Earth-sized planet that has survived the life cycle of its star and is orbiting a white dwarf. Astronomers have never found such a planet.
TESS’s launch window opens today, launching aboard a SpaceX Falcon 9 rocket.
After launch, TESS will be placed into an elliptical orbit around Earth which takes it past the orbit of the Moon. This unique orbit hasn’t been used for spacecraft before, however is expected to be super stable. Should TESS begin to drift from its orbit, the gravitational pull of the Moon will effectively kick it back into line.
This orbital stability means that TESS shouldn’t require much fuel to operate, giving it a potentially extremely long orbital life – with some estimating it could stably remain in orbit for 100 years or more.
All going well, TESS should be online and collecting data by as soon as June this year. And if TESS is anything like Kepler, there will be lots to see when that new data starts streaming in. It all starts today.