Live coverage: Two satellites lift off aboard Ariane 5

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.

Ground crews at the Guiana Space Center in South America have spent the last few months preparing the BepiColombo spacecraft, a tandem mission with European and Japanese science orbiters bound for Mercury, for launch aboard an Ariane 5 rocket.

A European environmental satellite rode a solid-fueled Vega launcher from a tropical spaceport at the edge of the Amazon jungle into polar orbit Monday night, adding a new eye in the sky to check on the health of crops and forests from space.