NASA's planet hunting probe completes lunar flyby

NASA's latest planet hunting satellite has successfully completed a lunar flyby - passing about 8,000 kilometres from the Moon - and beamed back a test image revealing more than 200,000 stars.

The flyby provided a gravity assist that helped the Transiting Exoplanet Survey Satellite (TESS) sail toward its final working orbit.

As part of camera commissioning, the science team snapped a two-second test exposure using one of the four TESS cameras. The image, centred on the southern constellation Centaurus, reveals more than 200,000 stars.

The edge of the Coalsack Nebula is in the right upper corner and the bright star Beta Centauri is visible at the lower left edge.

TESS is expected to cover more than 400 times as much sky as shown in this image with its four cameras during its initial two-year search for exoplanets.

A science-quality image, also referred to as a "first light" image, is expected to be released in June.

TESS will undergo one final thruster burn on May 30 to enter its science orbit around Earth. This highly elliptical orbit will maximise the amount of sky the spacecraft can image, allowing it to continuously monitor large swaths of the sky.

TESS is expected to begin science operations in mid-June after reaching this orbit and completing camera calibrations.

Launched from Cape Canaveral Air Force Station in Florida on April 18, TESS is the next step in NASA's search for planets outside our solar system, known as exoplanets.

The mission will observe nearly the entire sky to monitor nearby, bright stars in search of transits - periodic dips in a star's brightness caused by a planet passing in front of the star.

TESS is expected to find thousands of exoplanets. NASA's upcoming James Webb Space Telescope, scheduled for launch in 2020, will provide important follow-up observations of some of the most promising TESS-discovered exoplanets, allowing scientists to study their atmospheres.