Science News Roundup: 'NASA rules,' Musk says as SpaceX wins $2.9 billion contract; Scientists find only 3% of land area unblemished by humans and more

Following is a summary of current science news briefs.

'NASA rules,' Musk says as SpaceX wins $2.9 billion moon lander contract

NASA awarded billionaire entrepreneur Elon Musk's space company SpaceX a $2.9 billion contract to build a spacecraft to bring astronauts to the moon as early as 2024, the agency said on Friday, picking it over Jeff Bezos' Blue Origin and defense contractor Dynetics Inc. Bezos and Musk - the world's first and third richest people respectively, according to Forbes - were competing to lead humankind's return to the moon for the first time sine 1972.

Scientists find only 3% of land areas unblemished by humans

Very little of today’s world resembles Planet Earth from 500 years ago. In fact, only about 3% of land surfaces might be ecologically intact -- still home to their full range of native species and unblemished by human activity, according to new research. The finding -- published Thursday in the journal Frontiers in Forests and Global Change -- is far lower than previous estimates based on satellite images, which suggested around 20% to 40% of land ecosystems were undamaged.

Three astronauts return from International Space Station

Three members of the International Space Station's crew returned safely to Earth on Saturday on a Russian Soyuz craft, Russia's Roscosmos space agency reported. The Soyuz MS-17 spacecraft carrying NASA astronaut Kate Rubins, a microbiologist who in 2016 became the first person to sequence DNA in space, and Russian cosmonauts Sergey Ryzhikov and Sergey Kud-Sverchkov landed in Kazakhstan at 0455 GMT.

'Like Godzilla, but actually real': study shows T. rex numbered 2.5 billion

If one Tyrannosaurus rex - the school bus-sized meat-eating dinosaur that stalked the Cretaceous Period landscape - seems impressive, how about 2.5 billion of them? Researchers on Thursday unveiled the first calculation of the total T. rex population during the estimated 2.4 million years that this fearsome species inhabited western North America during the twilight of the age of dinosaurs.

(With inputs from agencies.)