One day last month, a barge floated along the Tennessee River toward NASA’s Alabama hub, the Marshall Space Flight Center. On board was a key piece of hardware for the agency’s Space Launch System, its new deep space exploration rocket.

The hardware – fabricated at the United Launch Alliance rocket plant a few miles away in Decatur – was a prototype of the interim cryogenic propulsion stage, or ICPS. The real thing will give the SLS’s Orion capsule the in-space push it needs to get beyond the moon.

Marshall will stack the ICPS with other test articles and simulators that make up the SLS’ upper portion so that engineers can conduct structural testing to make sure the components can withstand the pressures of the mission.

“Testing is probably the most important part of building a rocket,” said Steve Creech, acting director of the Spacecraft and Payload Integration and Evolution Office at Marshall.

Welcome to Alabama’s vibrant aerospace sector, where you just might spot a component for America’s Mars rocket being transported down a river. On the same day, if you’re in Mobile, you might see an Alabama-built Airbus A320 Family aircraft climb into the sky for a test flight.

In the ULA factory in Decatur, workers assemble the Atlas V and Delta IV rockets that blast critical communications and surveillance satellites into orbit. In Alabama, Raytheon and Lockheed Martin manufacture key missile defense systems.

Inside several facilities across the state, military helicopters and large jet aircraft are refurbished and repurposed. Alabama factories also produce the raw materials that end up as components in passenger jets and other aircraft.

“Alabama has been involved in aerospace at the highest levels for decades,” said Governor Robert Bentley, who is leading a state delegation at next week’s Farnborough International Airshow. “The industry in the state has developed a broad range of capabilities, meaning that Alabama workers are involved in just about every activity within aerospace, from design to manufacturing.

“Alabama is simply the perfect location for aerospace,” he added.

As industry leaders gather for the Farnborough show, Alabama’s aerospace industry is riding a wave of momentum that have seen substantial levels of new investment flow into the state.

Here’s a look at four trends that are helping to drive aerospace growth in Alabama.

TREND No. 1: DEEPENING EXPERTISE

Alabama is home to one of the heaviest concentrations of aerospace engineers in the nation – and their numbers are rising.

According to figures from the U.S. Bureau of Labor Statistics, Alabama is No. 5 among the states in the total number of aerospace engineers, with 4,200 as of May 2015. Figured as a share of total jobs, though, the figure is 450 percent higher than the U.S. average. That places Alabama No. 2 among the states, behind only Washington.

With 3,700 aerospace engineers, Huntsville ranks No. 3 among U.S. cities. That concentration is an incredible 35.7 times greater than the U.S. average, the second highest rate for a city, according to the BLS report.

Last year, Boeing opened a technology and research center in Huntsville, which today is staffed with 300 engineers, scientists, analysts and others. In Tallassee, GKN Aerospace launched an engineering design center that focuses on composite materials, boosting the number of skilled workers there.

Greg Canfield, secretary of the Alabama Department of Commerce, said recruiting aerospace jobs in fields such as engineering, research and design is a top priority of the state’s economic development team.

“We’re working hard to create these kind of high-skilled, high-paying jobs because we want to expand the deep level of aerospace expertise already found in the state,” Secretary Canfield said. “We want to see more products not only ‘Made in Alabama’ but also ‘Designed and Developed in Alabama.’”

TREND No. 2: NEXT-GENERATION TECHNOLOGIES

Boeing and other companies are working in Alabama to develop new materials and manufacturing techniques that will shake up the industry.

GE Aviation, an industry leader in innovation, is building adjacent plants in Alabama to mass produce unique silicon carbide materials that are instrumental to fabricate ceramic matrix composite components, or CMCs. The $200 million project is key to its plans to produce ultra-lightweight engine parts with CMCs.

In addition, GE Aviation is producing revolutionary fuel nozzles using additive manufacturing technology at a plant in Auburn, the first time a jet propulsion component has been mass produced using 3-D printing

“Without any doubt, the fuel nozzle is but the first of many parts that will be produced via additive manufacturing,” said Greg Morris, general manager of additive technologies with GE Aviation. “And Auburn is at the epicenter of this manufacturing revolution.”

These companies are being supported by Alabama universities, which have sent representatives to Farnborough for meetings. Auburn University and the Samuel Ginn College of Engineering are advancing additive manufacturing research and development for rocket engines and through a cooperative agreement with NASA, and the university is collaborating with GE Aviation.

The University of Alabama in Huntsville (UAH) is a longstanding partner of NASA and works with the U.S. military and aerospace companies in the Rocket City.

TREND No. 3: CRITICAL MASS

Alabama has become the scene of increased activity for aerospace projects. In 2015 alone, aerospace and aviation projects totaled nearly $500 million in new capital investment, along with around 1,500 jobs, according to a Commerce report.

One of those projects has strong air show ties. European space company RUAG announced plans in July 2015 to locate a manufacturing operation at ULA’s Alabama factory, where it will produce carbon-fiber components for the Atlas V rocket.

The project got started at the 2014 Farnborough Airshow, when Governor Bentley and Commerce Secretary Canfield met with RUAG Space’s Swiss executive team. Talks with ULA leaders about the collaboration took place at that Farnborough show and the next year at the Paris Air Show.

The growth has continued into 2016, with a $30 million expansion announced by UTC Aerospace Systems for its Baldwin County facility and plans by Sierra Nevada to open an aircraft modification center in Madison County with as many as 200 jobs.

TREND No. 4: ‘COOL FACTOR’

The wide range of aerospace activities taking place in Alabama has made the state an increasingly important player in aerospace and aviation. So does the long roster of industry heavyweights with a presence in the state.

“If you’re in aerospace, you need to be in Alabama,” Governor Bentley said. “It’s that simple.”

Marshall Space Flight Center plugs directly into Alabama’s aerospace history and its future, with the ambitious SLS program that aims to put a man on Mars.

As part of that project, Marshall is erecting a 215-foot tower where Boeing will conduct structural tests on the SLS’s fuel tanks. The rocket’s liquid hydrogen tank alone will stand 130 feet, and testing that will subject the tanks to enormous pressures could begin later this year.

Marshall says 2,150 tons of steel will be used to make Test Stand 4693, which is being built on the foundation of the stand where the Apollo Saturn V F-1 engine was evaluated in the 1960s.

Talk about cool factor.