What Caused The Ares I-X Parachute To Fail

To view a video of the Ares I-X parachute please go here.

Pull cord, deploy chute. Sounds simple, right? For the Ares I-X team the trick was in that "pull cord" step. After a thorough root cause analysis, NASA has pinpointed the likely culprit behind the Ares I-X parachute system anomaly - an errant cord yank that caused one reefing line pyro charge to fire prematurely while still in the parachute pack.

During the Ares I-X suborbital flight, the packed parachutes shook and shimmied inside the vehicle. Engineers believe the pack dynamics resulted in the snagging of a reefing line cutter lanyard, pulling the pin and activating the blade that cuts the line before the parachutes were deployed.

To understand what caused the early cut, it's important to understand how the parachutes are installed in the vehicle. The interior of the Ares I-X Forward Skirt Extension differs from the Shuttle frustum, an intentional design change.

Ares designers shortened a Y-shaped interior support structure to reduce the risk of snagging and damaging the fabric canopy during deployment. This design change provided more room for the parachutes but introduced an opportunity for them to move more than anticipated during the flight.

Post-launch Ares I-X video analysis taken from an on-board camera shows the parachute packs swinging side-to-side inside the vehicle. This movement, which was greater than expected, is the likely cause of the premature tug of the lanyard linked to the reefing line cutter.

Because the reefing line for the first reefing stage was cut prior to parachute deployment, the impacted canopy opened, or "dis-reefed," immediately to its second stage.

This created an overload condition on the parachute and a subsequent failure in its suspension system. The deflation of the first parachute created an additional overload condition on the remaining two parachutes prompting the partial failure of the second parachute.

Even overloaded, the damaged parachutes guided the hefty stage to splashdown only slightly tilted from vertical at water impact. The stage sustained some damage from the harder-than-nominal water impact but was still recovered yielding valuable onboard test data.

The engineering team redesigned the existing reefing line cutter pocket by lengthening the felt enclosure to encase the lanyard along with the reefing line cutter.

This design change will protect the lanyard from being snagged while inside the pack before the parachutes are deployed. NASA and partners will test this design, April 14, during the next scheduled parachute drop test at Yuma Proving Grounds, near Yuma, Ariz.

NASA's Marshall Space Flight Center, Huntsville, Ala., is responsible for project management of the Ares I first stage. ATK Launch Systems, Brigham City, Utah, is the prime contractor for the first stage booster. ATK's subcontractor, United Space Alliance, Houston, is responsible for the design, development and test of the parachutes at their facilities at the Kennedy Space Center, Fla. The U.S. Army's Yuma Proving Ground provides the test range, support facilities and equipment to NASA for parachute testing.

NASA’s Ares I-X Rocket Achieves Historic Hardware Milestones

NASA’s Constellation Program reached two major processing milestones this week as two new pieces of Ares I-X hardware were transferred for final assembly in preparation for the first flight test of the rocket later this summer at NASA’s Kennedy Space Center in Florida.

Once stacking operations begin later this month, it will be the first time a new vehicle has been stacked on NASA’s Mobile Launch Platform in more than 25 years.

The forward assembly, composed of the forward skirt, forward skirt extension and the frustum, was moved Thursday from Kennedy’s Assembly Refurbishment Facility, or ARF, to the Vehicle Assembly Building for stacking operations.

The aft skirt was moved Monday from the ARF to the Rotation Processing and Surge Facility to be attached to the aft motor segment, forming the aft assembly. The assembly will next move to the Vehicle Assembly Building for stacking on the Mobile Launcher Platform.

The Ares I-X rocket is a combination of existing and simulator hardware that will resemble the Ares I crew launch vehicle in size, shape and weight. It will provide valuable flight data to guide the final design of the Ares I, which will launch astronauts in the Orion crew exploration vehicle.

“This is a very exciting week for the team to have the hardware moving out of the ARF, showing how much progress we’ve made and that we are that much closer to launch,” said NASA Ares I-X mission manager Bob Ess of NASA’s Johnson Space Center in Houston.

The flight test of the Ares I-X will bring NASA one-step closer to its Constellation Program’s exploration goals of returning humans to the moon for sustained exploration of the lunar surface and missions to destinations beyond.

The forward assembly connects the 12-foot diameter first stage motor to the 18-foot diameter upper stage simulator. Weighing more than 40,000 pounds, the assembly houses three newly designed descent parachutes for first stage recovery.

The aft skirt, which is used at the bottom of the Solid Rocket Boosters for the Space Shuttle Program, was modified over the last year and a half for use on Ares I-X. Some modifications include adding deceleration and tumble motors, avionics and a controller for the auxiliary power unit.

“This week is the culmination of tremendous hard work and dedication by the entire NASA and contractor team,” said Joe Oliva, first stage program manager for the Ares I-X at ATK Space Systems in Salt Lake City. “These milestones are leading us to a flight test later this year that will provide our proof of concept data for NASA’s next generation of launch vehicles.”

United Space Alliance, of Houston, under a subcontract to ATK completed the processing and integration of the forward assembly and aft skirt. ATK is NASA’s prime contractor for the first stage of the Ares I rocket.