Communications with the spacecraft are established through the telecommunications subsystem, which includes uplink and downlink capabilities to support the telemetry and tracking functions. It interfaces with the ESA ground segment and the NASA Deep Space Network.

The subsystem includes:

• Three low-gain antennas
• A redundant set of transponders (including a NASA-supplied 10 W RF amplifier)
• An RF distribution unit and associated RF harnesses

Two low-gain antennas are mounted on deployable booms attached to the upper and lower faces of the spacecraft. They ensure full spherical coverage for uplinking and hemispherical coverage for downlinking. A third antenna mounted on the lower side of the spacecraft is used until the in-orbit deployment of the lower antenna boom.

	Data process
	Electrical power