I went to the Lockheed Martin College and Intern Hiring Event at the Omni Fort Worth Hotel. It was open to anyone with a computer science or engineering(electrical, industrial, software, aero, manufacturing, systems, mechanical) as well as a supply chain management degree. All those with the appropriate degree got interviews. I arrived their at 10:30 am (lines were open at 10 am... in retrospect I probably should have arrived around 9-9:30. the lines g get very long very quickly.) After waiting in line for a few hours and filling out some forms(asked for educational background and what sort of jobs I was interested in so they could select the appropriate interviewer) and handing in my resume I went to the main interview area. It in an open space with over a hundred tables and interviews. I was done with the interview around 3 pm. The interview(~20min) was short but unsurprisingly their the wait was several hours long.

Rigourous, multiple phases and they make sure that you are serious in defense contracting. Also check for your knowledge of certain systems related to the job posting. Do your research on them