Venkat might not be the flashiest scientist we meet at NASA, but the dude knows how to do his job.
Basically, Venkat has a simple leadership style. He doesn't big speeches like Teddy: in fact, he refuses "to make a speech" about Mark because "nice words [...] wouldn't bring him back" (6.5). Venkat is concerned with results, and his mind is already racing to figure out ways to turn this disaster into a net positive.
This aspect of his personality comes out time and time again. Venkat acts as the mediator when Mitch and Teddy get into their frequent arguments, weighing each side of the argument with Spock-like precision. In fact, Spock is a great comparison for the guy: for Venkat, it's all about the logic.
Like Annie Montrose and Mindy Park, Venkat is one of The Martian's less-lauded heroes. This might be because he has a smaller personality than dudes like Mitch and Teddy. Or it might be because Venkat simply prefers to work in the background. Regardless, his laser-sharp focus on rescuing Mark is crucial to the mission's success.