I always wondered, if we're already able to create these now and have space rockets. Imagine how life on other planets could already be observing us, just from a rocket they've sent out which is sending back data but it just takes a really long time for it to get back to their planet the further the rocket with the telescope is. Is there a possibility that could happen, or are telescopes in space impossible due to something?

There are like two questions in one here. I will try to answer as much as I can (am not too sure to get it right).

There are missions and future projects in space. For instance, the future eLISA mission that may be built for hunting gravitational waves, or AMS that is run from the international space station.

Now to go back to the question, we have no idea how evolved other civilizations could be and if they are already observing us, but we are free to dream. On the other side, we (as humans) are building missions to find them. It is not clear if we will ever meet anyone, but those telescopes built for astrophysics will not be the right tools to find them. They are tuned to other very specific purposed.