A reconnaissance party or recon party was a type of landing party sent with the goal of determining the situation in unfamiliar territory.
In 2267, Spock surmised that the USS Enterprise was occupied with another matter, as it had been an hour and twelve minutes since they were supposed to have sent a check-in signal and no reconnaissance party had come for them, despite Montgomery Scott's usually being quick to respond to such things. (TOS: "Friday's Child")
In 2268, R.M. Merik assured Captain James T. Kirk that his crew would arrive on the surface of 892-IV eventually, first sending a recon party, then subsequent rescue parties. He spoke from experience, as the crew of the SS Beagle ultimately emptied their ship in the same fashion. (TOS: "Bread and Circuses")