Stats: Delta 4 history and backlog (updated March 30)

A year after a launch mishap left Orbital ATK’s Cygnus supply ship without a ride to the International Space Station, company officials say the cargo delivery system is on the verge of a comeback, thanks to deals with United Launch Alliance and a decision to redesign its Antares booster with new rocket engines.

The first of up to seven missions planned on United Launch Alliance’s Atlas and Delta rocket fleets this year is scheduled for Saturday from California’s Central Coast, when a Delta 4-Heavy is set for blastoff on a spy satellite delivery flight delayed a month to troubleshoot a hydrogen fuel leak in a booster.

Good weather for launching a rocket is forecast for Cape Canaveral and the Space Coast on Thursday morning when a United Launch Alliance Atlas 5 is scheduled to take flight.