Science News Roundup: SpaceX capsule carrying NASA astronauts slated for August 2 return; Mexican cave artifacts show earlier arrival of humans in North America and more

Scientists said on Wednesday they had found 1,930 limestone tools, including small flakes and fine blades that may have been used for cutting meat and small points that may have been used as spear tips, indicating human presence at the Chiquihuite Cave in a mountainous region of Mexico's Zacatecas state.

Following is a summary of current science news briefs.

SpaceX capsule carrying NASA astronauts slated for August 2 return

The NASA astronauts who traveled to the International Space Station in SpaceX's first crewed flight in May are expected to return to Earth on Aug. 2 after spending two months in orbit, a NASA spokesman said on Friday. U.S. astronauts Bob Behnken and Doug Hurley will gear up for the final benchmark test of SpaceX's so-called Demo-2 mission: a coordinated splashdown somewhere in the Atlantic Ocean that will cap NASA's first crewed mission from U.S. soil in nearly a decade.

Mexican cave artifacts show earlier arrival of humans in North America

Stone tools unearthed in a cave in central Mexico and other evidence from 42 far-flung archeological sites indicate people arrived in North America - a milestone in human history - earlier than previously known, upwards of 30,000 years ago. Scientists said on Wednesday they had found 1,930 limestone tools, including small flakes and fine blades that may have been used for cutting meat and small points that may have been used as spear tips, indicating human presence at the Chiquihuite Cave in a mountainous region of Mexico's Zacatecas state.

China launches independent, unmanned Mars mission

China launched an unmanned probe to Mars on Thursday in its first independent mission to visit another planet, a bid for global leadership in space and display of its technological prowess and ambition. At 12:41 p.m. (0441 GMT), China's largest carrier rocket, the Long March 5 Y-4, blasted off with the probe from Wenchang Space Launch Centre on the southern island province of Hainan.

(With inputs from agencies.)