There is a low gain antenna (LGA) placed inside the HGA, similar to the LGA placement on Galileo. The LGA is used to provide omnidirectional coverage. It will be used for low transmission rates within close astronomical range. This LGA exists for redundancy, in case the HGA fails. Therefore the LGA is modeled after Galileo's LGA since it is functioning as the main communication for Galileo [7]. The frequency at which the LGA will communicate is 2.2 GHz with a power output of 100 W. The diameter of the LGA is calculated to be around 0.2 m. However the data rate is reduced to 10 bps in order for the diameter and power requirements to be satisfied.
The transmit antenna gain expected from the LGA is approximately 10 dB. Also the HGA is expected to transmit 10 bps if the receive antenna diameter is 70 m. The margin is also expected to be around 1 dB.
The LGA will be made from the same materials as used on the HGA.