In this week's Science Saturday, we look at science news ranging from Boeing's space mission to the world's oldest fossil forest.

Space exploration

Boeing's Starliner spacecraft has returned to earth from an unsuccessful mission. The unmanned ship – launched last Sunday in the U.S. state of Florida – was on a mission to the International Space Station, when it encountered an unexpected automation error, and failed to reach the correct orbit. The mission's failure is another setback for Boeing, who's been reeling from fatal crashes of its 737 MAX airliner. 

BeiDou Navigation Satellite System 

China has sent two more of its self-made BeiDou navigation satellites into space. The 52nd and 53rd of the BeiDou satellites were launched on a Long March-3B carrier rocket last Monday at the Xichang Satellite Launch Center in southwest China. It marks the completion of the core satellite constellation of the BeiDou-3 system. 

Ocean acidification

Climate change is threatening the world's most formidable marine predators. A recent study, based on a sample of three puffadder sharks, has found the rise of ocean acidity may corrode sharks' teeth and scales, and could further compromise the animals' ability to swim, hunt and feed. The study warns this outcome could cause disruptions in the entire oceanic food chain.

Nature discovery

Scientists have found the world's oldest known fossil forest in a sandstone quarry in the U.S. state of New York. The forest is located in the town of Cairo, dates back to about 385 million years ago, 150 million years before dinosaurs walked the Earth. Researchers say the discovery can offer insights into how trees transformed the planet and the link between forests and climate change.

"Science Saturday" is part of CGTN's science and technology series "Tech It Out." The segment brings you the latest news about innovations and technological breakthroughs in the past two weeks from across the world.