A critical connection between NASA's new rocket and its twin solid rocket boosters that will help it get to space proved it could withstand millions of pounds of launch stress during a series of ground tests that ended May 20.

The booster forward skirt, which houses the electronics responsible for igniting, steering and jettisoning the two five-segment boosters and carries most of the forces acting on the boosters during launch, is one of two places at the top and bottom of the booster where it is attached by struts to the Space Launch System (SLS) core stage. The core stage, towering more than 200 feet tall with a diameter of 27.6 feet, will store cryogenic liquid hydrogen and liquid oxygen that will feed the vehicle's RS-25 engines.

When completed, SLS will be capable of taking a crew and cargo on deep space missions, including to an asteroid and eventually Mars.

The five-segment boosters used during the launch of SLS will be the world's largest solid propellant rockets, measuring 177 feet long and 12 feet in diameter. ATK of Promontory, Utah, is the prime contractor for the boosters.

Loads on the hardware are forces -- primarily driven by mass and vehicle acceleration -- applied at different points on the vehicle. Structural loads tests are performed to ensure each piece of hardware can endure loads without any adverse effects to the vehicle, or most importantly, to the crew.

For the forward skirt test, conducted at ATK's facility in Promontory, engineers used increments of force -- about 200,000 pounds per minute -- to prove the design capabilities meet the strength requirements, with sufficient margin. The structure was also subjected to a combination of axial and lateral loads, which are critical at liftoff.

"Data will be reviewed over the coming weeks," said Brian Pung, SLS booster structures and assembly team lead at NASA's Marshall Space Flight Center in Huntsville, Alabama, where the SLS Program is managed. "We are very pleased with the initial results. Completion of this test brings us closer to use of this heritage hardware on SLS."

The team intentionally took the hardware beyond required margins -- not typical for structural loads testing on this scale.

"Attempting to take a structure of this size to failure is somewhat unique for structural testing," said Shane Canerday, forward assembly subsystem manager at the Marshall Center. "We want to know the exact amount of force the hardware can take to address capability differences that may exist across the fleet of heritage forward skirts."

The SLS 70-metric-ton (77 ton) initial configuration will launch an uncrewed Orion spacecraft to demonstrate the integrated system performance of the SLS rocket and spacecraft prior to a crewed flight. The massive 130-metric-ton configuration will be the most capable, powerful launch vehicle in history for crewed, longer duration missions.