Photos: Atlas 5 rocket aims for International Space Station

This gallery of photos shows the rollout Tuesday of United Launch Alliance’s Atlas 5 rocket and Boeing’s Starliner crew capsule to pad 41 at Cape Canaveral, plus additional views of the 172-foot-tall launcher standing next to the crew access tower Wednesday as teams prepared for a countdown rehearsal.

Near the end of a ground-shaking test firing of Northrop Grumman’s solid-propellant Castor 600 rocket motor — the first stage of a new booster being designed to launch spy satellites and other national security payloads — a major part of the rocket’s big nozzle appeared to break apart, littering the test site with shards of debris.

A $66 million NASA-funded science sensor package bolted on to a commercial communications satellite is ready for a ride toward a 22,000-mile-high orbital perch Thursday on a European Ariane 5 rocket, commencing a two-year mission surveying a rarely-studied region of Earth’s upper atmosphere.