Question: The Pratt & Whitney J58 was a jet engine that powered a long-range, Mach 3+ strategic reconnaissance aircraft operated by who?
Context: The Avro 730 was a planned Mach 3 reconnaissance aircraft and strategic bomber that was being developed by Avro Aircraft for the Royal Air Force (RAF).  It had been originally envisioned as a very high-speed aircraft to perform aerial reconnaissance missions, conforming with the requirements of Air Ministry Specification OR.330.  Avro subsequently decided to modify the design of the proposed 730 in order to accommodate its arming with nuclear weapons; this change therefore meant that the type would be able to perform the nuclear weapons delivery mission as well, which had been called for under Air Ministry Specification RB.156T which sought a high speed reconnaissance-bomber aircraft. Septuple meter (British: metre) or (chiefly British) septuple time is a meter with each bar (American: measure) divided into 7 notes of equal duration, usually or (or in compound meter, time).  The stress pattern can be 2+2+3, 3+2+2, or occasionally 2+3+2, although a survey of certain forms of mostly American popular music suggests that 2+2+3 is the most common among these three in these styles.  A time signature of , however, does not necessarily mean that the bar is a compound septuple meter with seven beats, each divided into three.  This signature may, for example, be used to indicate a bar of triple meter in which each beat is subdivided into seven parts.  In this case, the meter is sometimes characterized as "triple septuple time".  It is also possible for a time signature to be used for an irregular, or "additive" metrical pattern, such as groupings of 3 + 3 + 3 + 2 + 3 + 2 + 3 + 2 eighth notes.  Septuple meter can also be notated by using regularly "alternating" bars of triple and duple or quadruple meters, for example + , or + + , or through the use of "compound meters", in which two or three numerals take the place of the expected numerator 7, for example, , or . The 4028th Strategic Reconnaissance Squadron was a component of the 4080th Strategic Reconnaissance Wing, Strategic Air Command, that operated Lockheed U-2 spy planes out of Laughlin AFB, Texas, and Davis-Monthan AFB, Arizona, in the late 1950s and early 1960s.  The unit is also sometimes referred to as the 4028th Strategic Reconnaissance Weather Squadron.  It was from this unit that the pilots involved in overflights of Cuba during the Cuban Missile Crisis were drawn.  Detachments of the 4028th were deployed to Japan and South Vietnam. The Martin/General Dynamics RB-57F Canberra is a specialized strategic reconnaissance aircraft developed in the 1960s for the United States Air Force by General Dynamics from the Martin B-57 Canberra tactical bomber, which itself was a license-built version of the English Electric Canberra.  It was operationally assigned to the Air Weather Service for weather reconnaissance involving high-altitude atmospheric sampling and radiation detection in support of nuclear test monitoring, but four of the 21 modified aircraft performed solely as strategic reconnaissance platforms in Japan and Germany. The Republic XF-12 Rainbow was an American four-engine, all-metal prototype reconnaissance aircraft designed by the Republic Aviation Company in the late 1940s.  Like most large aircraft of the era, it used radial engines—in this case, the Pratt & Whitney R-4360 Wasp Major.  The aircraft was designed with maximum aerodynamic efficiency in mind.  The XF-12 was referred to as an aircraft that was "flying on all fours" meaning: four engines, 400 mph cruise, 4,000 mile range, at 40,000 feet.  It is still the fastest piston-engined airplane of this size, exceeding by some 50 mph the Boeing XB-39 of 1944.  Although highly innovative, the postwar XF-12 Rainbow had to compete against more modern jet engine technology, and did not enter production. The Lockheed SR-71 "Blackbird" is a long-range, Mach 3+ strategic reconnaissance aircraft that was operated by the United States Air Force.  It was developed as a black project from the Lockheed A-12 reconnaissance aircraft in the 1960s by Lockheed and its Skunk Works division.  American aerospace engineer Clarence "Kelly" Johnson was responsible for many of the design's innovative concepts.  During aerial reconnaissance missions, the SR-71 operated at high speeds and altitudes to allow it to outrace threats.  If a surface-to-air missile launch was detected, the standard evasive action was simply to accelerate and outfly the missile.  The SR-71 was designed with a reduced radar cross-section. The Tsybin RSR ("Reactivnyi Strategicheskii Razvedchik") was a Soviet design for an advanced, long-range, Mach 3 strategic reconnaissance aircraft. Turbine Fuel, Low Volatility, JP-7, commonly known as JP-7, was referred to as Jet Propellant 7, to MIL-DTL-38219 is a specific jet fuel that was developed for the United States Air Force (USAF), for use in its supersonic military aircraft that required a jet fuel with a high flash point, and high thermal stability.  JP-7 is the fuel that was developed, which was required by the Pratt & Whitney J58 (JT11D-20) turbojet engines, which was used primarily in the now retired Lockheed SR-71 Blackbird.  During flight, the SR-71 could attain speeds in excess of Mach 3+, which was the most efficient cruising speed for the J58 engines.  However, very high skin temperatures are generated at this speed due to friction with the air.  A new jet fuel was needed that was not affected by the heat, so JP-7 jet fuel was developed for this purpose. The Pratt & Whitney J58 (company designation JT11D-20) was a jet engine that powered the Lockheed A-12, and subsequently the YF-12 and the SR-71 aircraft.  The J58 was a single-spool turbojet with an afterburner.  It had a unique bleed from the compressor to the afterburner which gave increased thrust at high speeds.  This feature caused it to be referred to as a turboramjet in some writings.  It delivered 25,000 pound-force (110 kN) of thrust without afterburner (dry) and 34,000 (150 kN) with afterburner (wet). The Martin P4M Mercator was a maritime reconnaissance aircraft built by the Glenn L. Martin Company.  The Mercator was an unsuccessful contender for a United States Navy requirement for a long-range maritime patrol bomber, with the Lockheed P2V Neptune chosen instead.  It saw a limited life as a long-range electronic reconnaissance aircraft.  Its most unusual feature was that it was powered by a combination of piston engines and turbojets, the latter being in the rear of the engine nacelles.
Answer: United States Air Force