You may forget that this was a Federation outpost which the Shenzhou had been sent to investigate. Saru, Georgiou, and Burnham all concluded that there was no way of completing their investigation using the ship's instruments and probes. They even resorted to using Georgiou's "ancient" telescope to see if they could view the problem.Oh yes, in The Vulcan Hello, Mike Burns is straight up obnoxious in her efforts to sweet talk her captain into going out there to examine the mystery firsthand. She is super argumentative with Phillipa and Saru, both of whom value forbearance.
Having failed in every effort to determine the nature of the problem, there really is no other choice than to have someone to physically go out to view the problem.