I contacted them by email after watching a conference from SpaceX (NVIDIA GTC 2015). I got an answer within a few days and we scheduled a phone screen for the following week. A few hours before the phone screen I got contacted by HR to get various information about my GPA and school degrees. After the phone screen I was told I would have a second interview which I got a few days later. After the final interview I was told that I would be contacted by HR. In less than a 24H, HR told my that I was accepted for the intern.
The two interviews start by asking you to sum up your prior work experience. Then they ask you a series of questions. At the end you are given the opportunity to ask them questions.