While with NASA, the aircraft's tail number was 837; for the Quiet Spike program and Research Testbed it was 836, and 835 was used for the Highly Integrated Digital Electronic Control (HIDEC) program.
Sementara dengan NASA, pesawat nomor ekor adalah 837, untuk program Spike Quiet dan Penelitian TESTBED itu 836, dan 835 yang digunakan untuk program Highly Integrated Digital Electronic Control (HIDEC).