NASA is conducting its most powerful planet-hunting mission to date, with the launch of a new satellite to find "other Earths".

The Transiting Exoplanet Survey Satellite (TESS) will spend at least two years studying more than 200,000 nearby stars looking for "exoplanets" — planets like ours in other our solar system.

The Massachusetts Institute of Technology-led mission is currently scheduled to launch on April 16 from Cape Canaveral in Florida via a Falcon 9 rocket designed by Elon Musk's SpaceX.

It is expected to discover previously unknown worlds, ranging from smaller planets to much larger gas giants, including some that might host life.

TESS will be sent into Earth's orbit to perform observations with minimal interference from the atmosphere where some 500 earth-sized, 'mini-Earths' and “super Earth” planets are expected to be catalogued by the spacecraft.

It will also detect small rock-and-ice planets orbiting a diverse range of stars, including rocky worlds in the habitable zones of their host stars.

The planets will be identified by measuring small drops in light which occur when a planet passes across the face of its parent star.

Known as the "transit method", nearly 4,000 such planets have already been found using the same technique.

TESS Principal Investigator George Ricker, senior research scientist at the MIT's Kavli Institute, said that these planets will be the focus that astronomers will study "for centuries to come".

"And that’s the excitement that we have about this mission, is this is really a mission for the ages,” he said.

"There are a lot of things when you have an instrument that has this large of a field of view looking at the sky in an uninterrupted way, there’s just an incredible amount of science that will come out that we’re not even anticipating from TESS."

Weighing 362 kg and costing $243 million, it is seen as a more powerful successor to Nasa's earlier planet-hunting Kepler space observatory.

During its initial mission, Kepler looked at stars more than a thousand light-years away and has detected more than 2,500 confirmed planets.

Its capacity is dwarfed by TESS, however, which can view a section of sky more than 20 times greater than Keplar.

Ricker said that the "instantaneous field of view of the TESS cameras, combined with their area and detector sensitivity, is unprecedented in a space mission."

Nasa's most recent planetary discoveries include five exoplanets orbiting a sun-like star located within the constellation Aquarius, nearly 620 light years from Earth.

They are considered super-Earths, two to three times larger than our own.

Each scorchingly hot planet comes incredibly close to its star, streaking around in just 13 days at most in its orbit compared with Earth’s 365-day year.

Researchers credit these discoveries on "citizen scientists" — about 10,000 from the around the world — who have pored through publicly available data from K2, a follow-on to Kepler.

Ian Crossfield, assistant professor of physics at MIT, said that he hoped these citizen scientists would be able to analyse data taken by TESS in a similar way.

"We’re looking forward to more discoveries in the near future,” he said. "We hope that the TESS mission ... will also be able to engage the public in this way.