I responded to a posting on a job site advertising positions that require security clearances. I was contacted by HR for a phone interview with the local management on the project. After a 45 minute phone interview, I had no idea if I had done well. Two weeks later I was contacted for an on-site interview. The same individuals conducted the on-site.

Took one interview for them to give me an offer for an internship. Very relaxed one on one phone call. Strictly behavioral questions. I asked questions about the company and he answered very nicely.