On the Cover: We’re at the Cape! The design changes, the do-overs, the tests and retests are all done and LightSail has arrived at Cape Canaveral, Florida, ready for its launch to orbit on an Atlas V rocket. This will be LightSail’s shakedown cruise; we’re checking all its systems in preparation for our primary mission in 2016. This moment has been years in the making and a sometimes wild ride. Thank you for riding with us. Illustration: Josh Spradling
6 Countdown: Jason Davisdescribes the steps that got LightSail ready to fly.
13 Stories in Stone: Barbara Cohenlooks for planets' histories written in their rocks.
20 Protecting Our Planet: Bruce Bettsdetails gains made by NEO Grant winners.
22 We're On Our Way to Europa:Casey Dreier celebrates a new start for a long-desired mission.
2 Snapshots from Space A fresh look at Saturn.
4 Your Place in Space Bill Nyereflects on staying true to our original vision.