Nasa planet-hunting satellite launches today
Image credit: reuters
UPDATE: An 11th-hour technical glitch has prompted SpaceX to postpone its planned launch of the new telescope. The launch was halted two hours before launch and take off is now expected to happen on Wednesday.
Nasa is launching a new satellite on a SpaceX rocket that will aim to discover more exoplanets that might harbour life.
The Transit Exoplanet Survey Satellite, or TESS, will lift off from Cape Canaveral Air Force Station in Florida later today, starting the clock on a two-year, $337m mission in one of astronomy’s newest fields of exploration.
Once the delivery of the satellite into space has been completed, SpaceX will attempt to land the first stage of the two-stage Falcon 9 on a robotic ship stationed in the Atlantic Ocean.
To date, the company has pulled off such first-stage touchdowns 23 times during Falcon 9 launches, with about half of the boosters coming down on ‘drone ships’ and the other half returning to dry land.
TESS is designed to build on the work of its predecessor, the Kepler space telescope, which discovered the bulk of some 3,700 exoplanets documented by astronomers during the past 20 years and is about to run out of fuel.
Roughly the size of a refrigerator with solar-panel wings and equipped with four special cameras, the satellite will settle into a long, looping orbit around Earth and the Moon in June, at which point it can begin its planet-hunting mission in earnest. This orbit will be the first of its kind for an artificial satellite.
It could end up discovering thousands of such planets, mission officials have said, and Nasa expects that hundreds of them could be Earth-sized or “super-Earth”-sized – no larger than twice as big as our home planet.
Those are believed the most likely to feature rocky surfaces or oceans, and are thus considered the best candidates for life to evolve, as opposed to gas giants like Jupiter or Neptune.
Astronomers said they hope TESS will help catalogue about 100 more rocky exoplanets for further study.
“Putting stuff up in space is not without risk, but at this point there is nothing more we can do. We think we’ve got a spacecraft that is ready to kick ass once it’s up in orbit,” said Stephen Rinehart, the TESS project scientist at Nasa’s Goddard Space Flight Center.
“There are some people on the mission who are very, very, very keen to find Earth-sized planets in the habitable zones of their host stars and that would be absolutely fabulous.
“But the data on all these planets is interesting, because they help us form a picture of how planetary systems form and evolve. It’s going to be a game-changer in our ability to study planets.”
Like Kepler, TESS will use a detection method called transit photometry, which looks for periodic, repetitive dips in the visible light from stars caused by planets passing, or transiting, in front of them.
But unlike Kepler, which fixed its gaze on a range of stars within a tiny fraction of the sky, TESS will scan a broader swath of the heavens to focus on 200,000 pre-selected stars that are closer and thus among the brightest as seen from Earth.
That makes them better suited for sensitive follow-up analysis for the exoplanet candidates TESS locates.
The TESS survey will concentrate on stars called red dwarfs, smaller, cooler and longer-lived than our sun. Red dwarfs also have a high propensity for Earth-sized, presumably rocky planets, making them potentially fertile ground for closer examination.
And because the planets circling them are bigger relative to the size of the star, and orbit at a closer distance, the slight disruptions of visible light from their transits are more pronounced, scientists said.
Measuring blips in starlight can determine the exoplanet’s size and orbital path. Further observations from ground telescopes can supply its mass and ultimately the planet’s density and composition—whether largely solid, liquid or gas.
TESS itself will not detect life beyond Earth. But its most promising discoveries will undergo closer scrutiny by a future generation of larger, more powerful telescopes that will search for telltale signs of water and atmospheric gases that on Earth are indicators of life.