SCIENCE

The United States plans to test a spacecraft engine powered by nuclear fission by 2027 as part of a long-term NASA effort to demonstrate more efficient methods of propelling astronauts to Mars in the future, the space agency's chief said on Tuesday.

Astronaut Sultan Al Neyadi's mission to the International Space Station has been scheduled on Feb. 26.

About two billion tonnes of carbon dioxide are being removed from the atmosphere every year, according to a report published on Thursday, but nearly all of it is accomplished through forests, despite growing investments in new technologies.

The U.S. Department of Energy on Tuesday will announce that scientists at a national lab have made a breakthrough on fusion, the process that powers the sun and stars that one day could provide a cheap source of electricity, three sources with knowledge of the matter said.