Q&A with Scott Bolton, principal investigator on NASA’s Juno mission

Intermittent flows that appear on steep slopes on Mars are likely formed by flowing sand, and not water as some scientists previously suspected, according to a new study.

NASA’s Opportunity Mars rover, 14 years past its original 90-day design life, has dropped out of contact with Earth after powering down everything but its master clock in a bid to weather a huge dust storm that is blotting out the sun, preventing the solar-powered rover from recharging its batteries, mission managers said Wednesday.

The U.S. military’s next GPS navigation satellite was ready for launch from Cape Canaveral at 9:43 p.m. EDT Friday (0143 GMT Saturday) aboard a SpaceX Falcon 9 rocket. But SpaceX aborted the countdown just two seconds prior to liftoff.