Before the events of the film, obviously no. Helium did not have the resources to devote to extra-Barsoomian exploration. After the events of the film, and armed with the knowledge that the Thern were active on Jasoom, Dejah made it a priority to be able to watch and listen for advanced technology. Telescopes and radio arrays were deemed a security necessity.

So yes, she knows about Jasoom and she knows they're going to discover Barsoom is inhabited at some point. It's her hope that Barsoom is ready for them when they come.