The 100th rocket in America’s Evolved Expendable Launch Vehicle program, the current fleet of boosters used by the nation to get its critical assets into space, was rolled to the pad Friday morning for a vital mission on Saturday.

A threatening layer of clouds stayed away from SpaceX’s launch pad at Vandenberg Air Force Base in California on Tuesday, allowing for clear viewing of a spectacular Falcon 9 launch carrying commercial and scientific satellites into polar orbit.

Japan’s regional satellite navigation network, conceived to improve GPS coverage over Japanese territory, received its fourth member Monday with an on-target H-2A rocket launch.