Pressure-sensitive paint is being used as part of testing NASA’s most advanced launch vehicle, to be used in the agency’s Orion spacecraft on missions to explore deep space.

At NASA’s Langley Research Center in Hampton, Virginia, a scaled model of the SLS is undergoing testing using pressure-sensitive paint to evaluate the separation of the left and right solid rocket boosters from the rocket’s core. The painted model undergoes testing at Mach 4 (3,069 mph or 4,939 km/h) for the Block 1B cargo and crew vehicle.

“This is an important aerodynamic test in assuring that the boosters will cleanly separate from the center core of the vehicle and not pose a hazard to mission success,” said David Piatak, acting co-lead for Langley’s SLS Aerodynamics Team.

Pressure-sensitive paint allows engineers to gain “a visual of the flow and pressure on the model during separation,” said Courtney Winski, a researcher at Langley’s Configuration Aerodynamics Branch.

“It gives us more data on how it is going to separate, and possible effects on flow path.”

The rocket will send the Orion spacecraft on a mission travel thousands of miles beyond the Moon over the course of about three weeks.

Langley isn’t the only NASA center putting a SLS model through testing using pressure-sensitive paint, as NASA’s Ames Research Center in California’s Silicon Valley has done examinations using the paint.

This round of testing with the specialized paint job “uses high pressure air to simulate the exhaust plumes of SLS to allow us the opportunity to validate the very complicated flow fields being evaluated by computational fluid
dynamics,” she said.

“You find new things all the time,” Winski said. “This rocket must get up to 17,500 mph (28,163 km/h) to reach orbit and pass through the Earth’s thick lower atmosphere at transonic and low-supersonic speeds where aerodynamic forces play a large role in the structural design of the vehicle, in addition to keeping the pointy-end moving toward its orbital target,” Piatak said. “So we must perform a great deal of ground testing in wind tunnels to measure the aerodynamic forces on the vehicle as it plows through the atmosphere on its way to orbit.”

With thanks to Eric Gillard, NASA Langley Research Center