Reuters Science News Summary

Following is a summary of current science news briefs. NASA mulls buying new rides to space from Russia amid program delays

NASA said on Friday it was weighing an option to buy two additional astronaut seats aboard a Russian rocket as a contingency plan against further delays in the launch systems being developed by Elon Musk's SpaceX and Boeing Co. A possible purchase "provides flexibility and back-up capability" as the companies build rocket-and-capsule launch systems to return astronauts to the International Space Station (ISS) from U.S. soil for the first time since NASA's Space Shuttle program went dark in 2011. Antarctic ice shelves: Searching for clues on climate change

In a remote island outpost on the edge of the Antarctic, hundreds of miles from the southern tip of Chile, scientists at a research base are scouring the ice for clues about everything from climate change to cures for cancer. Chile's Escudero base on King George Island acts as a research hub for a frozen expanse that extends to the South Pole, with more than 300 international scientists taking turns to brave the bitter Antarctic temperatures. NASA bids adieu to Opportunity, the Mars rover that kept going and going

Opportunity, a remarkably durable NASA rover designed to roll along the surface of Mars for three months, has stopped communicating with Earth after 15 years of service, officials said on Wednesday, ending a mission that astounded the U.S. space agency. Engineers lost contact with the solar-powered vehicle on June 10 during a dust storm that encircled Mars. Since then, NASA officials made numerous attempts to reach the six-wheeled rover, which is about the size of a golf cart.