Live coverage: Ariane 5 rocket deploys satellites for Australia, India

Blaming a slew of technical snags and “avoidable errors,” NASA officials said Tuesday that the launch of the James Webb Space Telescope, already years behind schedule, will be delayed to 2020, potentially pushing the mission’s development cost above an $8 billion cap mandated by Congress.

The first in a planned multi-decade series of European land imaging satellites is fastened on top of a solid-fueled Vega launcher at a French Guiana space base for liftoff Monday, kicking off a mission to track everything from global crop growth to urban sprawl.

SpaceX’s launch team loaded liquid propellants into the company’s first upgraded Falcon 9 Block 5 rocket Friday at the Kennedy Space Center in Florida, and the countdown rehearsal culminated in a brief ignition of the launcher’s nine Merlin main engines on the launch pad.