[bashinator]

Mars is smaller than Earth, so planet-wide radio interferometry would be a smaller "aperture" than possible on Earth. If you're talking about extending the telescope to include both Earth and Mars, I imagine that doing the interferometry over changing speeds and distances would be challenging to say the least.

[aurailious]

The speeds and distances of the planets are well known at this point and easily predicted. By the time of establishing a permanent presence on Mars the requirements of communications would already put in place the information needed if the DSN isn't already capable of it now. The compute needed would be greater, but so would the availability of it in the future too.