Hi LW-community

I discovered LW a few years ago.
My favorite Star Wars-author (Matthew Stover) posted on Facebook, that he had just read HPMOR and that he recommended it.I read it (multiple times) and loved it. So inquired if there was more to read from EY and ended up here. I love the concept of LW but so far found myself unable to contribute.
Today I want to throw a thought into this pool.

Again, a few years ago I realized, that this is the first time in the history of our planet that life has the ability to spread from Earth into outer space.Earth has eventually proceeded into adolescence and became fertile.

But how long will that fertility persist?

And, what, if Earth was the only planet in the entire universe that hosted life? I don't want to discuss probabilities, I don't even believe that, but it is possible.
Then, our responsibility to make use of that fertility would be enormous, and we should do it quickly, too, before we lose the ability, again. 

Since we can not find a suitable planet and neither have the technology to travel there in time, yet, we will need to send some other life form to act as earth-sperm.

From here on I need support - do you agree with me so far?

My rough idea, supposed to serve as a base for discussion, is this:
Put frozen tardigrades in bullets. Put a giant railgun in space and shoot as many of them away in random directions as possible and hope that in millions of years of time one will find a place to settle. Bullets might contain some tardigrade-food(?), also they should somehow pop open when impacting on anything like a planet, but without killing the tardigrades (maybe contact with water?). Maybe tardigrades can be replaced by a better species. Maybe there is a better transportation system.

I apologize if this post does not meet the LW-standards. I trust this community very much and want to gather feedback and maybe even possibly allies.