Question: X-15 is a film that fictionalized the research rocket that set speed records in what decade?

Context paragraphs:
Rudolf Caracciola: Otto Wilhelm Rudolf Caracciola (30 January 1901 – 28 September 1959), more commonly Rudolf Caracciola (] ), was a racing driver from Remagen, Germany.  He won the European Drivers' Championship, the pre-1950 equivalent of the modern Formula One World Championship, an unsurpassed three times.  He also won the European Hillclimbing Championship three times – twice in sports cars, and once in Grand Prix cars.  Caracciola raced for Mercedes-Benz during their original dominating Silver Arrows period, named after the silver colour of the cars, and set speed records for the firm.  He was affectionately dubbed "Caratsch" by the German public, and was known by the title of "Regenmeister", or "Rainmaster", for his prowess in wet conditions.

Reaction Motors: Reaction Motors, Inc. (RMI) was an early American maker of liquid-fueled rocket engines, located in New Jersey.  RMI engines with 6000 lbf thrust powered the Bell X-1 rocket aircraft that first broke the sound barrier in 1947, and later successors including the X-1A, X1E, and the Douglas D-558-2 Skyrocket.  A 20000 lbf thrust RMI engine also powered the Viking research rocket, the first large liquid-fueled US high-altitude rocket.  RMI was merged with Thiokol in 1958, where it produced the XLR-99 engine that powered the X-15 rocket aircraft.

North American X-15: The North American X-15 was a hypersonic rocket-powered aircraft operated by the United States Air Force and the National Aeronautics and Space Administration as part of the X-plane series of experimental aircraft.  The X-15 set speed and altitude records in the 1960s, reaching the edge of outer space and returning with valuable data used in aircraft and spacecraft design.  The X-15's official world record for the highest speed ever recorded by a manned, powered aircraft, set in October 1967 when William J. Knight flew Mach 6.72 at 102100 ft , a speed of 4520 mph (2020.278 meters per second), has remained unchallenged as of .

Terrier Malemute: The Terrier Malemute is a two-stage American sounding rocket typically used for smaller payloads (less than 180 kg ).  Both the Terrier first stage and the Malemute second stage use solid fuel.  The Terrier burns for approximately 5.2 seconds, and the Malemute burns for approximately 21.5 seconds.  The first stage booster consists of a surplus Navy Terrier MK 12 Mod 1 rocket motor with four 340-square-inch (0.22 m) fin panels arranged in a cruciform configuration.  The Terrier rocket booster has a diameter of 18 inches (460 mm).  The second stage solid rocket is a Thiokol Malemute TU-758 rocket motor, specially designed for high altitude research rocket applications.  Apogee is approximately 400 km (220 nmi) for a 500 lb (230 kg) payload or 700 km (380 nmi) for a 91 lb (41 kg) payload.  For a payload weight of 200 lb (91 kg), the acceleration during the boost phase is 26 "g".

Harley-Davidson Model W: The Harley-Davidson Model W, also known as the "Sport Twin", is a motorcycle made by Harley-Davidson from 1919 to 1923.  Unusually for a Harley-Davidson motorcycle, the Model W had a flat-twin engine and a trailing link fork.  The Model W set speed records on runs from New York City to Chicago and from the Canada–United States border to the Mexico–United States border.  Slow home market sales led to the end of production after four years.

X-15 (film): X-15 is a 1961 dramatic aviation film that presents a fictionalized account of the X-15 research rocket aircraft program, the test pilots who flew the aircraft, and the associated NASA community that supported the program.  "X-15" starred David McLean, Charles Bronson, Mary Tyler Moore (in her first feature film role), Kenneth Tobey and James Gregory.  The film marked the directorial debut of Richard Donner, and was narrated by James Stewart.

Jean Chassagne: Jean Chassagne (26 July 1881 La Croisille-sur-Briance – 13 April 1947) was a pioneer submariner, aviator and French racecar driver active 1906-1930.  Chassagne finished third in the 1913 French Grand Prix; won the 1922 Tourist Trophy and finished second in the 1925 Le Mans Grand Prix d'Endurance - all in Sunbeam motorcars.  He was second in the 1921 Italian Grand Prix with a Ballot, and set speed records and won races at Brooklands and hill climbs internationally.

Hit-and-miss engine: A hit-and-miss engine is a type of four-stroke internal combustion engine that is controlled by a governor to operate a set speed.  It was conceived in the late 19th century and produced by various companies from the 1890s through approximately the 1940s.  The name comes from the speed control on these engines: they are designed to fire ("hit") only when operating at or below a set speed, and to cycle without firing ("miss") when they exceed their set speed.  This is as compared to the "throttle governed" method of speed control.  The sound made when the engine is running without a load is a distinctive "POP whoosh whoosh whoosh whoosh POP" as the engine fires and then coasts until the speed decreases and it fires again to maintain its average speed.

Donald Campbell: Donald Malcolm Campbell {'1': ", '2': ", '3': ", '4': "} (23 March 19214 January 1967) was a British speed record breaker who broke eight absolute world speed records on water and on land in the 1950s and 1960s.  He remains the only person to set both world land and water speed records in the same year (1964).  He died during a speed attempt at the Lake District in northern England.

Patrick Stirling (footballer): Patrick Stirling (5 November 1862 − 1925) was a Scottish footballer who played for Doncaster Rovers and was Mayor of Doncaster.  His father, also called Patrick Stirling, was Locomotive Superintendent of the Great Northern Railway and designer of the 4-2-2 steam locomotive Stirling single that set speed records during the race to the north.

Supporting paragraphs: X-15 (film) North American X-15
Answer: 1960s