The USAP is run under the auspices of the United States' National Science Foundation (NSF) and as a government agency is funded through taxpayer dollars. The program's yearly budget is estimated at $200M. The NSFs role in Antarctica is to promote and facilitate research. Participants in the USAP are NSF grantees and USAP support staff.
The USAP sole purpose is to support the United States' scientific research operations in Antarctica, as initiated by the NSF. The USAP provides logistics, infrastructure, and training for NSF grantees operating on the ice. Though originating as the US Military's Operation Deep Freeze the modern USAP is a civilian operation. The New York Air National Guard participates only as the primary carrier of personnel from New Zealand to the ice.
The USAP operates three year-round stations in Antarctica. The largest and primary base is at McMurdo Station on Ross Island. Palmer Station is on the Antarctic Peninsula and is the most northerly. Pole Station, a.k.a. Scott-Amundsen Pole Station is exactly where the name suggests.
While the principal participants in the USAP are scientists, engineers, and support workers, artists and writers can receive a trip to Antarctica courtesy of the American taxpayer by applying to and being accepted by the NSFs Antarctic Artists and Writers program run by the Office of Polar Programs.
USAP logistics and operations is handled by RPSC, who provides employment on the ice for USAP support staff.