The aperture size of transmitter and receiving antenna are sized to keep the maximum beam intensity at or below 245 W/m2. This is only one quarter of the intensity of sunlight at midday, which is around 1,000 W/m2.
So it could be testing the feasability of the next sattelite that will be a weapon with a different aperture size.
Alternatively they are using google and their webmail client, no windows mail needed.