Context_1 : Space Exploration Technologies Corp., doing business as SpaceX, is an American aerospace manufacturer and space transport services company headquartered in Hawthorne, California. It was founded in 2002 by entrepreneur Elon Musk with the goal of reducing space transportation costs and enabling the colonization of Mars. SpaceX has since developed the Falcon launch vehicle family and the Dragon spacecraft family, which both currently deliver payloads into Earth orbit. Context_2 : Richard Hornsby & Sons was an engine and machinery manufacturer in Lincolnshire, England from 1828 until 1918. The company was a pioneer in the manufacture of the oil engine developed by Herbert Akroyd Stuart, which was marketed under the "Hornsby-Akroyd" name. The company developed an early track system for vehicles, selling the patent to Holt & Co. (predecessor to Caterpillar Inc.) in America. In 1918, Richard Hornsby & Sons became a subsidiary of the neighbouring engineering firm Rustons of Lincoln, to create "Ruston & Hornsby". Context_3 : Since the founding of SpaceX in 2002, the company has developed four families of rocket engines — Merlin, Kestrel, Draco and SuperDraco — and is currently developing another rocket engine: Raptor. Context_4 : The Kestrel engine is an LOX/RP-1 pressure-fed rocket engine. The Kestrel engine was developed in the 2000s by SpaceX for upper stage use on the Falcon 1 rocket. Context_5 : Biopure Corporation was a biopharmaceutical company that specialized in oxygen therapeutics (blood substitutes) for both human and veterinary use. The company developed, manufactured, and marketed oxygen therapeutics, designed to transport oxygen to the body's tissues. The oxygen technology uses hemoglobin-based oxygen carrying molecules in solution (HBOCs) to increase oxygen transfer to the tissues. The competing companies with Biopure were Allied Pharmaceutical, Northfield Laboratories, Baxter International and Hemosol of Toronto. The company developed two products: Hemopure (HBOC-1) <nowiki>[hemoglogin glutamer-250 (bovine)]</nowiki> for human use, and Oxyglobin (HBOC-301) <nowiki>[hemoglobin glutamer-200 (bovine)]</nowiki> for veterinary use. As of April 2001, Hemopure was approved for commercial sale in South Africa for treatment of acute anemia in general surgery. However, Hemopure has not been able to gain approval in the U.K. or the U.S. because of safety and reliability concerns of the European Commission and the U.S. Food and Drug Administration (FDA) respectively. The company formed an agreement with the U.S. Navy to aid in preclinical testing of Hemopure for out-of-hospital treatment of trauma patients in hemorrhagic shock. Oxyglobin is the only oxygen therapeutic approved for treatment of canine anemia in both Europe and the U.S. and has treated thousands of cases. Unable to obtain FDA approval for Hemopure to date, Biopure ceased operations in 2009 and its assets were purchased by OPK Biotech LLC in September 2009. On July 16, 2009 Biopure announced it had filed for bankruptcy protection under Chapter 11, Title 11, United States Code and entered into an agreement with OPK Biotech LLC for the sale of substantially all of its assets . Context_6 : The Hawker P.1127 and the Hawker Siddeley Kestrel FGA.1 were the experimental and development aircraft that led to the Hawker Siddeley Harrier, the first "vertical and/or short take-off and landing" (V/STOL) jet fighter-bomber. Kestrel development began in 1957, taking advantage of the Bristol Engine Company's choice to invest in the creation of the Pegasus vectored-thrust engine. Testing began in July 1960 and by the end of the year the aircraft had achieved both vertical take-off and horizontal flight. The test program also explored the possibility of use upon aircraft carriers, landing on HMS "Ark Royal" in 1963. The first three aircraft crashed during testing, one at the 1963 Paris Air Show. Context_7 : The Rolls-Royce Peregrine was a 21 l , 885 hp liquid-cooled V-12 aero engine designed and built by the British manufacturer Rolls-Royce in the late 1930s. It was essentially the ultimate development of the company's Kestrel engine, which had seen widespread use in military aircraft of the pre-war period. Context_8 : The Rolls-Royce Eagle XVI was a British experimental 16 cylinder aero engine designed and developed by Rolls-Royce Limited in 1925. The engine was test run but did not fly, the project was cancelled in favour of the Rolls-Royce Kestrel that was being developed concurrently. Context_9 : Dimadis-Kanakis (since 1986 Kanakis E.P.E.) is a historic Greek engine and metal products manufacturer, based in Volos. It was founded in 1920 by Pavlos Dimadis and Ioannis Kanakis, initially focusing on engine repair and rebuilding. In 1926 the company developed and produced its first semi-diesel engines (10-60 hp, mostly for boat power). Soon an extended range of engine models, up to 120 hp, was developed and the company became one of the best known Greek engine makers, mostly remembered for the reliability of its products. Some exports were also made. Context_10 : The Rolls-Royce Buzzard (also referred to as the H engine) was a British piston aero engine of 36.7 L capacity that produced about 800 hp . Designed and built by Rolls-Royce Limited it featured 12 cylinders in a 'V' configuration of 6 in bore and 6.6 in stroke. It was manufactured in the late 1920s, but only 100 were sold. A further development was the Rolls-Royce R Schneider Trophy engine. The Buzzard was developed by scaling-up the Kestrel engine in the ratio of 5:6. fact_1 :  The Kestrel engine was developed in the 2000s by SpaceX for upper stage use on the Falcon 1 rocket. fact_2 : Space Exploration Technologies Corp., doing business as SpaceX, is an American aerospace manufacturer and space transport services company headquartered in Hawthorne, California. Question: What company developed the Kestrel engine?
Output: SpaceX