They will join two NASA astronauts and a Russian cosmonaut on board the station, effectively doubling the amount of time that can be spent on research.
The planets are rocky and 1.75 times the size of Earth, and are being referred to as ‘super-Earths’ or ‘mini-Neptunes’.
Scientists used the Hubble Space Telescope to plot minute changes in the path of light coming from a distant background star as it passed by the relatively close star Stein 2051B.
The astronauts will venture outside to replace a computer that recently failed, leaving the space station to depend on a backup system.
The space plane took off in May 2015 and conducted unspecified experiments for more than 700 days while in orbit, the programme’s fourth mission so far.
The discovery makes Saturn’s ocean-bearing moon Enceladus the only place beyond Earth where scientists have found direct evidence of a possible energy source for life.
It took Space Exploration Technologies Corp, as the California-based company is formally known, 15 years to demonstrate that a rocket typically discarded in the ocean after a single flight could be recovered and reused.
SpaceX CEO Elon Musk declined to identify the customers or say how much they would pay to fly on the weeklong mission, except to say that it is “nobody from Hollywood.”
The company, controlled by billionaire Elon Musk, wants to improve the design of its engines to increase performance and resolve potential safety concerns.
Evidence suggests Pluto harbours a hidden ocean beneath the frozen surface of its central plain containing as much water as all of Earth’s seas.
Scientists believe asteroids and comets crashing into early Earth delivered water and organic compounds that seeded the planet for life.
Jeff Williams, Alexey Ovchinin and Oleg Skripochka made a parachute descent southeast of Zhezkazgan.
Scientists announced the largest single finding of planets to date, using a new analysis technique that applied statistical models to confirm the batch as planets, while ruling out scenarios that could falsely appear to be orbiting planets.
The Earth-sized planets are orbiting their parent star, located in the constellation Aquarius relatively close to Earth at 40 light years away, at a distance that provides the right amount of heat for there to be liquid water on their surface, a condition scientists believe may be critical for fostering life.
The successful autonomous touchdown of the booster at sea marked another milestone for billionaire entrepreneur Elon Musk.