Live coverage: Atlas 5 countdown and launch journal

NASA has awarded SpaceX a $109 million contract to launch the Interstellar Mapping and Acceleration Probe, a NOAA space weather observatory, a robotic scout to map water on the moon, and two other ridealong payloads on a single Falcon 9 rocket from Cape Canaveral in 2024.

Arianespace’s launch team loaded an Ariane 5 rocket full of super-cold liquid hydrogen and liquid oxygen propellants Tuesday for a fiery sunset blastoff from French Guiana at 2139 GMT (4:39 p.m. EST) with two European-built television broadcast satellites for Brazil and Indonesia.

NASA announced Thursday it will fund four concept studies for potential robotic missions to Venus, Jupiter’s moon Io and Neptune’s moon Triton ahead of a decision next year to approve up to two of the projects for launch in the mid-to-late 2020s.