From Space

Objectives are small side missions within the Horde mode missions. They show up every second wave, so the higher the difficulty you set, the more missions you’ll have to complete which increases the chance you’ll find one you’re missing.

If I’m missing any objectives, please let me know!

Objectives:

• Activate the instruments
• Complete the sequence
• Retrieve the data
• Transport the Item
• Activate the console

Important Note: ‘Transport the Item’ was the only objective I was missing, and only showed up for me while playing the map Hatchery and Missile Silo

This achievement didn't pop after completing my last missing objective and only popped after fully completing the mission.