Launch Date: December 23, 2017
Window: 01:26:22 - 01:48:22 UTC
Launch Site: Tanegashima Space Center
Launch Vehicle: H-IIA 202
Payload: GCOM-C1 (1,950kg), SLATS (400kg)
Ascent Duration: 1 Hour & 48 Minutes
Target Orbit: 788 x 806km, 98.68° (GCOM), 450 x 643 km, 98.3° (SLATS)

Japan's H-IIA rocket is set for liftoff from the picturesque Tanegashima Space Center on Saturday, December 23 on a dual-satellite delivery mission targeting two different orbits. Hidden under the vehicle's payload fairing is the 1,950-Kilogram GCOM-C1 Global Change Observation Mission for Climate spacecraft outfitted with a 19-channel imaging instrument to study Earth's carbon cycle and radiation budget over an extended time scale relevant for climate assessments.

After sending GCOM-C1 on its way 800 Kilometers in altitude, H-IIA will be tasked with lowering its orbit to deploy the Super-Low Altitude Test Satellite for a mission orbiting on the edge.

Falcon 9 - Iridium-4

Launch Date: December 23, 2017
Time: 01:27:34 UTC
Launch Site: SLC-4E, Vandenberg
Launch Vehicle: Falcon 9 FT
Payload: 10 Iridium-NEXT (860kg each)
Ascent Duration: 72 Minutes
Target Orbit: 615 x 625 km, 86.66°
First Stage Recovery: No

SpaceX's Falcon 9 rocket is set for a post-sunset liftoff from California with the next ten Iridium-NEXT communications satellites that will push the Iridium replacement effort beyond its halfway point with forty upgraded satellites in orbit after the mission. The fourth Iridium flight of the year will mark the 18th final Falcon 9 to launch in 2017, closing a record-setting year for SpaceX.

Iridium-4 is the first mission for Iridium employing a flight-proven first stage, featuring Falcon 9 Booster 1036 that lifted the Iridium 11-20 satellites into orbit in June 2017.