Q&A with Eric Smith, JWST program director

A work stoppage at the Ariane 5 rocket’s launch base in South America prevented rollout of the booster to the launch pad Monday, pushing back the liftoff of two communications satellites for Brazil and South Korea until at least Wednesday.

Forecasters predict a 90% chance of good weather for liftoff of a United Launch Alliance Atlas 5 rocket from Cape Canaveral just after sunset Tuesday with a classified payload for the National Reconnaissance Office, the U.S. government’s spy satellite agency.

A powerful Ariane 5 rocket rolled out of its vertical assembly hangar to a tropical launch pad on the shores of South America on Monday, and these photos show the booster on the eve of liftoff.