NASA satellite to hunt for planets orbiting other stars

NASA is to launch a new planet-hunting satellite that will use an array of cameras to study the brightest stars in the sky.

The $200m Transiting Exoplanet Survey Satellite (TESS) project, led by researchers at the Massachusetts Institute of Technology (MIT), will monitor the closest stars to the Sun for evidence of planets passing in front of them, following its launch in 2017.

‘TESS will carry out the first space-borne all-sky transit survey, covering 400 times as much sky as any previous mission,’ said principal investigator George Ricker, a senior research scientist at the MIT Kavli Institute for Astrophysics and Space Research (MKI).

‘It will identify thousands of new planets in the solar neighbourhood, with a special focus on planets comparable in size to the Earth.’

TESS’s cameras will enable the researchers to study the masses, sizes, densities, orbits and atmospheres of many small planets, including a sample of rocky worlds in the habitable zones of their host stars.

It will also provide prime targets for further characterisation by the James Webb Space Telescope, as well as other large ground-based and space-based telescopes of the future.

Previous sky surveys with ground-based telescopes have mainly picked out giant exoplanets. NASA’s Kepler spacecraft has recently uncovered the existence of many smaller exoplanets, but the stars Kepler examines are faint and difficult to study.

In contrast, TESS will examine a large number of small planets around the very brightest stars in the sky, identifying them as they pass (transit) in front of the stars.

‘The TESS legacy will be a catalogue of the nearest and brightest main-sequence stars hosting transiting exoplanets, which will forever be the most favourable targets for detailed investigations,’ Ricker said in a statement.

The project relies on several innovations developed by the MIT team over the past seven years, he added. ‘For TESS, we were able to devise a special new ‘Goldilocks’ orbit for the spacecraft — one which is not too close, and not too far, from both the Earth and the moon.’

This means that TESS will regularly come close enough to the Earth for high data-downlink rates once every two weeks, while remaining above the planet’s harmful radiation belts.

This special orbit will remain stable for decades, keeping TESS’s sensitive cameras in a very stable temperature range.

The other TESS team partners are MIT Lincoln Laboratory, NASA’s Goddard Spaceflight Center, Orbital Sciences Corporation, NASA’s Ames Research Center, the Harvard-Smithsonian Center for Astrophysics, The Aerospace Corporation, and the Space Telescope Science Institute.

NASA has also announced a mission to be mounted on the International Space Station (ISS) that will measure the variability of cosmic X-ray sources in order to learn about neutron stars.

The Neutron Star Interior Composition Explorer (NICER) mission aims to explore the exotic states of matter within neutron stars and reveal their interior and surface compositions.