Search the buses near the western gate

How do you complete "Search the buses near the western gate"?

This is step 1 of 2 in A Wrench in the Works, given by Celeste. It is completed on The Spaceport.

• A Wrench in the Works
• The Spaceport

What are the other objectives in A Wrench in the Works?

A Wrench in the Works has 2 objectives in total: Search the buses near the western gate and Locate the stash of sabotage supplies hidden at the Water Towers.