The first five aircraft were delivered as Martin MB-2s but the last 15 were given the designation NBS-1 (Night Bombardment - Short Distance) in the new USAAS designation system; the first five were redesignated NBS-1 in 1921. The NBS-1 was such a success that the USAAS wanted 110 more but as mandated by the Congress, the Army was required to ask for bids on the additional aircraft. The lowest bid was by the Curtiss Aeroplane and Motor Company of Garden City, New York, which priced their aircraft US$6,000 (US$69,500 in 2007 dollars) less per plane than Martin so Curiss got the contract for 50 NBS-1s. A second contract for 35 aircraft was awarded to the L.W.F. Engineering Corporation of College Point, New York; four of these aircraft had dual controls for training. The last 20 Curtiss machines had turbo-superchargers while L.W.F.s first NBS-1 was sent to the Aeromarine Plane and Motor Company of Keyport, New Jersey, and used as a pilot model for 20 NBS-1s built by that company.
Beginning in 1919, General Mitchell became more and more vocal on the subject of aviation claiming that aviation was just as important as ground and naval forces. He was sure that airplanes rendered Navy battleships obsolete but there were many people opposed to this idea including Army generals and Navy admirals who saw aviation as a supporting force to ground forces and the fleet. Mitchell proposed a test of airplanes versus ships in 1919 but the tests were not conducted until June and July 1921. The USAAS was invited to join the Navy in tests against four ex-German warships, a submarine, a destroyer, a cruiser and a battleship, anchored about 50 mi (80 km) off Cape Charles, Virginia.
The first test was conducted on the submarine U-117; Naval aircraft sank this ship. The second target was the destroyer G-102. The initial attack was carried out by Royal Aircraft Factory S.E.5As followed by 16 NBS-1s. Flying at 1,500 ft (457 m), each NBS-1 dropped two 300-lb (136 kg) bombs and the destroyer began to sink. Five days later, it was the cruiser Frankfurt's turn. This ship was attacked by NBS-1s carrying 600-lb (272 kg) bombs; the cruiser sank 35-minutes later. The final test was against the battleship Ostfriesland. The ship was attacked in the morning by NBS-1s carrying 1,100-lb (499 kg) bombs followed in the afternoon by NBS-1s with 2,000-lb (907 kg) bombs. Mitchell ordered his pilots to drop their bombs in the water near the ship and after two bombs were dropped, the ship sank. Mitchell had proved that airplanes could sink ships.
The NBS-1s equipped front line squadrons until 1930 when they were replaced by Keystone bombers. Those squadrons, and the years they operated this aircraft, were as follows.
2d Bombardment Group, 2d Wing, Third Corps Area, U.S. Army based at Langley Field, Hampton, Virginia:
11th Bombardment Squadron (1921-1927)
20th Bombardment Squadron (1921-1927)
49th Bombardment Squadron (1921-1928)
96th Bombardment Squadron (1921-1929)
4th Composite Group, Philippine Department, U.S. Army based at Camp Nichols, Luzon, Philippine Islands:
28th Bombardment Squadron (1924-1930)
5th Composite Group, Hawaiian Department, U.S. Army based at Luke Field, Oahu, Territory of Hawaii:
23d Bombardment Squadron (1922-1929)
72d Bombardment Squadron (1923-1929)."