It had originally been scheduled for use in Project Orbit tests, a program of simulated manned orbital flights in the McDonnell vacuum chamber.

Static article No.1, which had been intended for load tests of the paraglider, ejection seat, hatch, and cabin pressurization, was redesignated spacecraft No. 3A and replaced spacecraft No. 3 in the Project Orbit test program. A McDonnell review of the entire static test program in December 1962 had resulted in eliminating static article No. 1 and making static articles Nos. 3 and 4 the primary structural test articles. No. 3 was subjected to launch, reentry, abort, landing, and parachute loads; and No. 4 to seat, hatch, and pressurization loads plus dynamic response tests.