The Grumman Rigel was a Navy cruise missile designed to fly 400 to 500 nm at Mach 2. In May 1950, the Navy planned to get the Regulus operational in 1953, Rigel operational in 1955, and the "ultimate cruise missile," the Triton, operational in 1960. Plans called for a Marquardt ramjet to power Rigel, whose all-up weight was 19,000 pounds with booster. However, because there were no facilities large enough to test the 48-inch ramjet, the testers used a 28-inch version. This powered a six-tenth's scale test model which first flew in March 1950. But the program encountered what proved to be insoluble problems. By October 1952, 11 of the flight tests had failed. Therefore, the Navy canceled Rigel in August 1953.