If you're going to assume heavy equipment on the other end (ours or "someone else's"), it's not ridiculously beyond our current capabilities to simply transmit DNA sequences along with enough digital training material to "grow" and raise a human population from scratch.

Not to mention the reliability and throughout requirements of such a data link to another planet so far away.

has a mammalian fetus ever been developed to maturity outside of a natural womb?

40 light years isn't a big deal if humans lived to be thousands of years old. That's another solution.

Or cryogenically freeze yourself with instructions to be brought back in a few millennia near the new star system. From the observer's point of view you could be there Tuesday week or so.

Why not just make that first payload contain actual humans? Seems a helluva lot simpler.

Yup, for several hundred thousand year's journey. No problem. :-)

I would just hope my emacs session will stay up that long.

Interstellar tramp.

There are moments of pure beauty in the universe.

You could, and probably would. But, how would you send everyone else? That 'traditional' method (carbon based fuels to propel a heavy payload) is extremely expensive, and slow. So if you ever wanted to send more than just 1 payload, you'd quickly reach resource limitations (namely cost, and time).

Why would you need to send more? Humans are natural von Neumann machines.

I hate to always post links to Greg Egan, but he's sort of the XKCD of SciFi - if there's an out there concept, he's usually written a book about it. In this case Incandescence:

https://www.amazon.com/dp/B0070YQOHW

Top review has the best summary: "Egan's story is set in the galactic core, inhabited by a race known as the Aloof, because they seem almost indifferent to any attempts at communication from the Amalgam, the loose network of civilizations that inhabit the rest of the galaxy. However, they do allow thrill-seeking members of the Amalgam to enter their transportation network, digitizing themselves for transmission at the speed of light across the galactic core, instead of the long way around it."

Why humans? People are concerned about the survivability of human species, and it's certainly a noble goal, but at this point it's outside or technological reach. Preserving life, in the other hand, could be doable. We «just» need to take some prokaryotic cells to one of those planets, assuming they have the right environment, and in some million years you have a complete ecosystem...

Assuming also, of course, that there is not life there already.

The whole idea of digitizing humans is silly. It would lead to spooky action at distance. For example what if when humans are digitized you send it to two different machines? Which one would be the real you?

I think the magic speed is actually 10% the speed of light.

What's magic about it?

It's fast enough to get us places in a reasonable amount of time (40-200 years), but reasonably attainable technologically.