A Rainfield Simulator for Hypersonic Testing

The U.S. Army Space and Missile Defense Command Technical Center’s Aerophysics Research Facility, (ARF), fired a successful hypersonic shot to test its new rainfield simulator.

February 1, 2026

U.S. Army Space and Missile Defense Command Technical Center, Huntsville, AL

The U.S. Army Space and Missile Defense Technical Center’s Aerophysics Research Facility fired a successful hypersonic shot Dec. 11 to test its new rainfield simulator. The image was taken using high speed camera of a conical nose impacting a single stream of water droplets at about Mach 10. (Image: U.S. Army)

Zack Perrin, ARF manager and technical lead engineer of the U.S. Army Space and Missile Defense Command (USASMDC’s) Targets and Test Resources Branch of the Ronald Reagan Ballistic Missile Defense Test Site, said ARF is SMDC’s premier hypersonic flight and hypervelocity impact laboratory. Perrin said their largest gun system, the 254 mm light gas guns, or LGGs, is the fastest gun in the Army and can launch projectiles 6 inches in diameter to speeds up to 3 kilometers per second or smaller projectiles on the order of 2.7 inches in diameter to velocities exceeding 6 km/s.

“I like to tell people that the facility is a gun range the size of an aircraft carrier and within the facility are multiple engineering tools, called light gas guns,” Perrin said. “Aerophysics’ core mission is to efficiently and affordably provide both the Army and the broader Department of Defense (DoD) engineering community with state-of-the-art hypersonic aerodynamic data, hypervelocity impact physics data, and weapons system performance data.”

The eventual goal is to be able to characterize and model vehicle reactions with rainfields at hypersonic velocity.

“An artificial rainfield is exactly what it sounds like,” Perrin said. “Essentially, we have a reservoir filled with water that has a series of hollow needles of a given size coming out of it, that have water droplets flowing out of them. These reservoirs and needles are precision aligned to our gun’s shotline and highly modular, allowing us to change the size of the water drops, spacing of the drops, and the number of droplet streams that the projectile travels through.

“This test and its predecessors have been highly successful,” he added. “Our team has performed phenomenally and has captured incredible data. In addition to pushing the bounds of data acquisition, the team has really hit their stride in test execution. We are currently on track to execute three hypervelocity shots on our largest gun system, in three weeks, with three different projectiles, at three different velocities, for two different customers.”

Matthew Intardonato, SMDC Concepts Analysis Division General Engineer, said the December test was the third in a recent project, but was the first test that utilized a projectile other than a sphere.

“We’re currently working on a research project dedicated to developing diagnostic techniques for imaging and acquiring data on the effects that rain has on hypersonic vehicles,” Intardonato said. “Our first two experiments launched 2.7” diameter nylon spheres, similar in size to a baseball, up to speeds around Mach 8, that traveled through a series of artificial rainfields induced throughout the 254 mm flight range. A core objective of these first two tests was to evaluate and gain experience operating advanced imaging capabilities and optical diagnostics systems developed over the proceeding months by the team.

“We were still highly successful in evaluating multiple advanced imaging methods as potential approaches to capturing experimental test data,” he added. “Almost every test is different, that’s what makes the job so fun.”

Intardonato said typically the test begins with establishing customer requirements, which are always different between customers, and then comes the design of experiment, which is really the make or break of a test.

“Once we’ve designed the experiment, we focus on the buildout and configuration implementation,” Intardonato said. “This is where the rubber meets the road and the team gets their hands dirty. When the gun goes off, everyone is behind two feet of concrete and instead of a resounding boom that everyone expects, it’s much more of a relatively quiet thud. After that, it’s saving and processing data, cleaning up the gun, and recycling to either repeating a test or going back to configuration build out.”

Intardonato said the level of flexibility and success the team has achieved so far would not be possible without the team’s commitment, incredible experience level, and combined teamwork.

“Ultimately, the ARF supports the warfighter by providing the Army and DoD with experimental data to enable engineers to build better and more lethal weapons systems,” Intardonato said. “By increasing the experimental body of knowledge available to weapons system designers, warfighters benefit in having better engineered tools and proven information at their disposal.”

This article was written by Jason Cutshaw, Public Affairs Specialist, U.S. Army Space and Missile Command. It has been edited. For more information, visit here .