Assassin's Creed Origins
67 Achievements
1,500
76-92h
Project Comet
Craft an upgrade using Shards of a Star (The Curse of the Pharaohs)
20
3.22%
How to unlock the Project Comet achievement in Assassin's Creed Origins - Definitive Guide
If you boosted to level 45 with this DLC, this should also pop Handy Man.
To unlock this achievement, you'll have to craft one of the final two tiers of upgrades for your gear. This means you'll have to have already upgraded it to max yellow level in the main game, then crafted the next two upgrades with Carbon Crystals in The Hidden Ones DLC. If you've done that (which you absolutely should have while progressing) then you'll have access to two more upgrade tiers. Crafting the first upgrade in a new tier will unlock this achievement.
In addition to the usual bronze, stone, pelts, etc., that you need for upgrades, you'll also need a bunch (20-30 for the good gear) of the Shards of a Star. The only ways to get this epic crafting item are either by killing Pharaoh's Shadows, which spawn randomly all around the main map, or by killing the giant scorpions in the Afterlife. The former have varying levels and basically play like boss fights, making them more of a pain. The scorpions are extremely easy to kill, especially on horseback. In Aaru, the first Afterlife region, there are lots of scorpions you can ride around killing. Kill all the ones you see to make sure you get plenty of Shards of a Star. You won't need to farm any scorpions though, since you have to kill 5 or so Pharaoh's Shadows as part of the story and will likely get more Shards of a Star.
Once you've got enough for an upgrade, craft it and the achievement will unlock.