Jensen Huang: "Elon is an extraordinary engineer. He is singular in his understanding of engineering and construction and large systems and marshaling resources."

John Carmack: "Elon is definitely an engineer. He is deeply involved with technical decisions at SpaceX and Tesla. He doesn’t write code or do CAD today, but he is perfectly capable of doing so."

Tom Mueller: "Elon is a super smart guy and he learns from talking to people. He’s so sharp, he just picks it up. He is leading the development of the SpaceX engines, particularly Raptor."

Eric Berger: "Elon is the chief engineer in name and reality."

Andrej Karpathy: "Elon has an incredible ability to reason from first principles. It’s very rare."

Robert Zubrin: "Elon Musk is a brilliant engineer with an extraordinary ability to cut through nonsense. When I met him it was apparent to me that although he had a scientific mind and he understood scientific principles, he did not know anything about rockets. Nothing. That was in 2001, by 2007 he knew everything about rockets – he really knew everything, in detail. You have to put some serious study in to know as much about rockets as he knows now. This doesn't come just from hanging out with people."

Yann LeCun: "He’s a very smart guy and I’m in awe of some of his projects."

Garrett Reisman: "He’s obviously skilled at all different functions, but certainly what really drives him and where his passion really is, is his role as Chief Engineer. That’s the part of the job that really plays to his strengths."

Josh Boehm: "Elon is both the Chief Executive Officer and Chief Technology Officer of SpaceX, so of course he does more than just some very technical work. He is integrally involved in the actual design and engineering of the rocket, and at least touches every other aspect of the business. Elon is an engineer at heart, and that’s where and how he works best."

Kevin Watson: "Elon is brilliant. He’s involved in just about everything. He understands everything. If he asks you a question, you learn very quickly not to go give him a gut reaction. He wants answers that get down to the fundamental laws of physics. One thing he understands really well is the physics of the rockets. He understands that like nobody else. The stuff I have seen him do in his head is crazy. He can get in discussions about flying a satellite and whether we can make the right orbit and deliver Dragon at the same time and solve all these equations in real time. It’s amazing to watch the amount of knowledge he has accumulated over the years."