Solar Turbines
A Caterpillar subsidiary that designs and manufactures industrial gas turbines and integrated turbomachinery systems.
Last updated October 14, 2026
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Overview
Solar Turbines is an American industrial gas-turbine manufacturer headquartered in San Diego, California, and wholly owned by Caterpillar Inc. Its equipment is used for electrical power generation, mechanical drives, natural-gas compression, oil and gas production and processing, pipeline transmission, marine propulsion, and other industrial applications. The company operates primarily in business-to-business markets, supplying turbine packages, compressors, generators, mechanical-drive systems, controls, service agreements, parts, upgrades, and emissions-related technologies rather than consumer products. The business traces its roots to the Prudden-San Diego Airplane Company, established in 1927. After the company became Solar Aircraft Company in 1929, its initial attempt to sell an all-metal trimotor aircraft was undermined by the Great Depression. Solar subsequently built a stronger business producing specialized aircraft components, particularly stainless-steel and other high-temperature parts. Wartime demand expanded the workforce substantially, and the company became involved in components for military aircraft and early jet engines. Solar’s aerospace work led management to invest in compact gas-turbine technology. Beginning in the 1940s, the company developed turbines for auxiliary power, emergency shipboard electricity, portable equipment, and other military uses. Designs such as the Mars, Titan, and Saturn established technical capabilities that could be transferred to commercial industrial markets. The Saturn, introduced around 1960, became especially important as a packaged industrial turbine for generator sets, compressor drives, and pump applications. Solar’s products found a significant market in the natural-gas industry, where turbine-driven compressors could operate along transmission systems and at production facilities. International Harvester acquired Solar Aircraft Company around 1960 and reorganized it as the Solar Division in 1963. During the 1960s and 1970s the division broadened its industrial range, introducing larger turbine families such as the Centaur and a later, substantially larger Mars line. In 1973 it left the aerospace sector to focus on industrial turbines. International Harvester separated the radial-engine activities into a Radial Engine Group in 1975; that operation became the Turbomach Division in 1980. Caterpillar acquired the assets of the Solar and Turbomach divisions on May 31, 1981, and organized them as Solar Turbines Incorporated. The acquisition gave Caterpillar a specialized industrial-turbomachinery business that complemented its broader construction, energy, and power-equipment activities. Caterpillar later sold the Turbomach Division to Sundstrand Corporation in 1985, while Solar Turbines continued developing axial-flow industrial engines and packaged systems. Solar announced the Titan 130 in 1997, extending the Titan name into a much larger industrial class than the original small turbine. Environmental performance became an important part of the company’s product strategy. Solar introduced its SoLoNOx lean-burn combustion system in 1992 to reduce nitrogen-oxide emissions from industrial turbines. The technology could be specified on newer equipment and retrofitted to installed units. The company also pursued efficiency and materials research, including ceramic hot-section work and recuperation studies conducted with support from the United States Department of Energy. Solar’s current portfolio is centered on the Saturn, Centaur, Mercury, Taurus, Mars, and Titan families, together with generator sets, compressor packages, mechanical-drive equipment, controls, service, and modernization solutions. The business serves both onshore and offshore installations and supports equipment throughout its operating life. According to the referenced company history, Solar has delivered more than 15,000 gas-turbine systems with a combined operating history exceeding two billion hour…
History
Solar Turbines began as the Prudden-San Diego Airplane Company, founded in 1927 by aircraft engineer George Prudden and seven San Diego-area businessmen. Differences between Prudden and his investors led him to leave the enterprise in 1928. The company changed its name to Solar Aircraft Company in 1929, reflecting its San Diego location and climate. Its first major product was an all-metal passenger trimotor powered by three Siemens & Halske radial engines. The aircraft was difficult to market during the Great Depression, and only three were produced. Solar shifted instead toward manufacturing components for other aircraft companies. Its specialties included difficult, high-temperature parts such as stainless-steel exhaust manifolds. By 1939 the company employed 229 people, and World War II orders drove rapid expansion. By the end of the war its workforce had reached roughly 5,000, while it had produced more than 300,000 exhaust manifolds for American aircraft. Postwar demand fell sharply. Solar explored a range of unrelated products, including caskets, frying pans, milk containers, furniture, and a small racing car. Its high-temperature metallurgy and precision-manufacturing capabilities nevertheless created an opportunity in the emerging jet-engine field. The company produced components for several early American and allied engines, including the General Electric I-40, Allison J33 and J35, Avro Canada Orenda, and Bristol Olympus. It also built an afterburner for the Westinghouse J34 under a United States Navy contract. Engineer Wendell Reed developed a pneumatic microjet controller and received the Wright Brothers Medal in 1955 for the work. Solar president Edmund Price believed gas turbines could become important prime movers. In 1946 the company established a turbine development effort under Paul Pitt. Its first small axial-flow design was intended as an auxiliary power unit for the Convair B-36 bomber, although the Army contract was cancelled. A Navy contract followed in 1947 for a 250-kilowatt shipboard emergency-power system. The resulting T-400 first ran in 1949 and later served on minesweepers and landing craft. Solar also supplied auxiliary power units for the first 632 KC-135A tanker aircraft. A second design effort led by Leon Wosika and Eric Balje developed a compact centrifugal-flow turbine. Initially called the MPM-45 and later marketed as the 45-horsepower Mars, it was used by the Navy for portable firefighting pumps. A larger 55-horsepower design was developed for the Gyrodyne XRON-1 helicopter program and became the Titan, later designated T62 by the Navy. Although the helicopter project was abandoned, the Titan was adapted as an auxiliary power unit, with deliveries beginning in 1962. Other derivatives included the Spartan and Gemini. In the late 1950s the Navy requested a larger turbine for a high-speed boat. Solar responded with the axial-flow Saturn, which entered production in 1960 and was subsequently marketed to industrial users. The Saturn became one of the world’s most widely deployed industrial gas turbines, with thousands of systems sold internationally. Solar developed complete packages around the engine, including generator sets, pump drives, and gas-compressor systems. These packages were particularly useful in natural-gas pipeline and processing applications. International Harvester acquired Solar Aircraft Company in early 1960 and reorganized it as the Solar Division in 1963. During the following decade the division introduced additional turbine platforms, including the Centaur, which entered service in 1968, and a larger Mars line introduced in 1977. In 1973 the division exited aerospace to focus exclusively on industrial turbines. International Harvester separated radial-engine activities in 1975, creating a Radial Engine Group that was renamed the Turbomach Division in 1980. On May 31, 1981, Caterpillar Tractor Co. bought the assets of the Solar and Turbomach divisions. The assets were organized as Solar Turbines Incorporated, a wholly owned Caterpillar subsidiary. Caterpillar also assigned Solar responsibility for development and manufacturing of the Model 5600, a gas turbine originally developed by Boeing. In 1985 Caterpillar sold the Turbomach Division to Sundstrand Corporation, while Solar continued as Caterpillar’s industrial gas-turbine business. During the 1980s and 1990s Solar introduced new and upgraded axial-flow engines, often extending established product-family names. The Titan 130 was announced in 1997, and later Titan development continued toward much larger industrial systems. Solar also invested in emissions and efficiency improvements. Its SoLoNOx system, introduced in 1992, used lean-burn combustion to reduce nitrogen-oxide emissions and was made available for both new turbines and retrofits. Other development work included ceramic hot-section research for the Centaur 50 and a recuperated Mercury 50 project conducted with the United States Department of Energy. Caterpillar’s 2004 acquisition of Swiss Turbomach S.A. strengthened its broader turbine-packaging capabilities. Solar Turbines remains active as a Caterpillar subsidiary, supplying the Saturn, Centaur, Mercury, Taurus, Mars, and Titan families together with generator sets, compressor packages, mechanical drives, controls, parts, upgrades, and service. Its customers include energy companies, pipeline operators, industrial facilities, offshore installations, and marine users. The company’s historical development is characterized by a transition from aircraft manufacturing to high-temperature components, military turbine technology, and finally a global industrial turbomachinery business.
- 2004
Caterpillar acquires Turbomach S.A.
[1]The acquisition added a Swiss turbine packager to Caterpillar’s broader energy and turbomachinery organization.
- 1997
Titan 130 announced
[1]The Titan 130 expanded Solar’s industrial turbine range to approximately 19,500 horsepower.
- 1992
SoLoNOx introduced
[1]Solar introduced lean-burn combustion technology intended to reduce nitrogen-oxide emissions.
- 1981
Solar Turbines becomes a Caterpillar subsidiary
[1]Caterpillar acquired the Solar and Turbomach assets and created Solar Turbines Incorporated.
- 1977
Larger Mars introduced
[1]Solar launched a much larger industrial Mars turbine, separate from the earlier small Mars design.
- 1973
Aerospace activities discontinued
[1]Solar ended its aviation business and concentrated on industrial gas turbines.
- 1968
Centaur enters service
[1]Solar introduced the Centaur turbine family, initially rated at approximately 2,700 horsepower.
- 1963
Solar becomes an International Harvester division
[1]The business was reorganized as the Solar Division of International Harvester.
- 1960
International Harvester acquires Solar
[1]International Harvester purchased Solar Aircraft Company around the time the Saturn entered production.
- 1947
Navy turbine contract begins
[1]Solar began developing a 250-kilowatt turbine system for emergency shipboard power; the resulting T-400 first ran in 1949.
Products and positioning
A global industrial turbomachinery specialist focused on reliable, packaged gas-turbine systems and lifecycle support for power generation, oil and gas, pipeline, marine, and other demanding industrial applications.
Industrial axial-flow gas turbine · 1960
Saturn
The Saturn is one of Solar’s foundational industrial turbine families. It originated as a larger naval turbine in the late 1950s and entered production around 1960. Solar adapted it for industrial generator sets, compressor drives, pump packages, and other mechanical-drive duties. Its broad international deployment helped establish Solar as a major supplier to the natural-gas and energy infrastructure sectors.
Industrial gas turbine · 1968
Centaur
The Centaur family was introduced in the late 1960s as a larger industrial turbine platform. It has been used in power generation and mechanical-drive applications, including compressor and pump systems. Later versions increased output substantially, and Solar also investigated ceramic hot-section technology for the Centaur 50 as part of its efficiency and durability development work.
Industrial gas turbine
Mercury
The Mercury family represents Solar’s work in efficient industrial turbine design and advanced cycle development. The company investigated a recuperated Mercury 50 in cooperation with the United States Department of Energy. Mercury systems are intended for industrial power and drive duties where fuel efficiency, compact packaging, and emissions performance are important operating considerations.
Industrial gas turbine
Taurus
Taurus turbines are part of Solar’s modern industrial portfolio and are offered for distributed power generation and mechanical-drive applications. They can be integrated into packaged systems with generators, compressors, controls, and emissions equipment. Detailed model-level specifications are not established in the supplied reference material.
Gas-turbine family · 1947
Mars
The Mars name has been used for two distinct stages of Solar’s history. The original small centrifugal-flow Mars was developed for naval portable firefighting equipment. A later industrial Mars, introduced in the 1970s, was a much larger axial-flow turbine used for power generation and gas compression. Modern versions include the Mars 90 and Mars 100 designations.
Gas-turbine family · 1956
Titan
The original Titan was a compact turbine derived for a naval auxiliary-power and helicopter-related application. Solar later reused the name for a much larger industrial axial-flow family. The Titan 130 was announced in 1997, and subsequent development produced higher-output models including the Titan 250. Titan systems serve industrial power-generation and mechanical-drive markets.
Low-emissions combustion technology · 1992
SoLoNOx
SoLoNOx is Solar’s lean-burn combustion technology for reducing nitrogen-oxide emissions from industrial gas turbines. Introduced in 1992, it became available for new turbine designs and retrofit programs. The system is part of Solar’s response to increasingly stringent emissions requirements in power generation, oil and gas, and industrial installations.
Brand decisions
2004
Caterpillar acquires Turbomach S.A.M&ABackground
Turbomach S.A. had experience packaging industrial turbines from Solar, Rolls-Royce, and other manufacturers for energy-sector customers.
Action taken
Caterpillar acquired the Swiss company, reinforcing its turbine integration and packaging capabilities.
Aftermath
The transaction strengthened Caterpillar’s broader industrial-energy organization alongside Solar Turbines.
1992
Launch SoLoNOx emissions technologyProduct launchBackground
Industrial turbine customers faced growing pressure to limit nitrogen-oxide emissions while maintaining power and mechanical-drive performance.
Action taken
Solar introduced a lean-burn combustion system that could be installed on new turbines and retrofitted to existing equipment.
Aftermath
SoLoNOx became a recurring feature of Solar’s product strategy and was reportedly retrofitted to more than 2,000 turbines according to the supplied reference.
1985
Sell the Turbomach DivisionM&ABackground
After acquiring the Solar and Turbomach assets, Caterpillar retained the Solar industrial turbine business but did not continue owning the separate centrifugal-engine operation.
Action taken
Caterpillar sold the Turbomach Division to Sundstrand Corporation.
Aftermath
Solar remained Caterpillar’s principal industrial gas-turbine subsidiary, while the divested operation later became associated with Collins Aerospace through corporate succession.
1981
Caterpillar acquires Solar and Turbomach assetsM&ABackground
International Harvester’s Solar and Turbomach operations represented specialized industrial turbine capabilities that complemented Caterpillar’s heavy-equipment and power-related businesses.
Action taken
Caterpillar Tractor Co. purchased the assets on May 31, 1981 and organized them as Solar Turbines Incorporated.
Aftermath
Solar continued as a wholly owned Caterpillar subsidiary and became part of Caterpillar’s long-term energy and industrial-equipment portfolio.
1973
Concentrate exclusively on industrial turbinesStrategyBackground
Solar’s aerospace operations had developed valuable turbine and high-temperature-material expertise, but the company increasingly saw industrial energy equipment as its strategic focus.
Action taken
The Solar Division exited the aerospace industry and redirected resources toward industrial gas-turbine design, manufacturing, packaging, and support.
Aftermath
The decision established the industrial-turbomachinery orientation that defines Solar Turbines today.
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