From Steam, but not on Gog (yet):

Hey everyone! We’ve just issued a huge Tharsis patch with bug fixes, new missions, a completely revamped tutorial, unlockable skull avatars, and more. We’ll post the full patch notes below, but I first wanted to remind everyone that they can always contact us at support@totallychoice.com with any bug reports, support requests, or anything else they’d like to chat with us about. We’re dedicated to making Tharsis the best game it can possibly be, so please don’t be shy about sending your feedback our way!

PATCH NOTES

Bug fixes galore
A completely revamped tutorial. We highly recommend you play through it if you’ve had a hard time understanding Tharsis!
Introduction of unlockable “skull” avatars. We’ll talk more about the unlock criteria as time goes on. For now, we want to see how many of you can figure it out without our assistance…
Smoother difficulty curve in Normal mode
Hard mode is now harder than ever
Five new missions available in Missions mode
Research mechanic now more streamlined and easier to understand

Yeah, someone posted about this on the subreddit for the game asking how people felt about the "big patch" and I was like, wait, what big patch?

I hope it doesn't take too much longer to get over here, since it seems the patch came out on Steam almost three weeks ago...

Not only the Tharsis mission is doomed, the patch on Gog as well. When I update Tharsis through Galaxy, it does nothing. When i download the setup file through Gog, it installs version GOG4 (the 'August' patch). I confirm this is the new version of the game with an easy mode, 5 new missions and the skull objectives.

When I then run Galaxy again and do a rescan folder, Galaxy downloads the old installation file again, replacing GOG4 with the obsolete GOG3 version.

Weird.

I hope you're not trying to patch the Galaxy-installed game with the stand-alone installer, that is usually a bad idea.

I don't know why Galaxy hasn't been updated to provide the latest release of the game. I stopped using Galaxy a long time ago for various reasons, you can add this to the list as well.