Thursday, July 30, 2015

Lockheed Martin Successfully Tests Design Changes for Orion Spacecraft’s Fairing Separation System

An Orion fairing panel separates during a June test at Lockheed Martin's facility in Sunnyvale, California. Three fairing panels encase Orion's service model to protect it during ascent to space and are jettisoned once they are no longer needed. Credits: Lockheed Martin

NASA’s prime contractor for Orion, Lockheed Martin, successfully completed two ground-based tests to evaluate how Orion’s fairing panels will separate from the spacecraft on its way to space. The tests incorporated several changes designed to reduce spacecraft mass and help further prepare Orion for its first mission atop NASA’s Space Launch System (SLS) rocket to a distant lunar orbit. Lessons learned from last year’s flight test and building the initial spacecraft have provided valuable insight to inform these design improvements.

Orion includes three massive fairing panels that encase the service module, which houses power and propulsion, during the spacecraft’s climb to space. Like common rocket fairings, the panels support the spacecraft and help it endure the aerodynamic pressure, heat, wind and acoustics it encounters as it goes from sitting on the launch pad to traveling thousands of miles per hour in a matter of minutes. But unlike conventional fairings, Orion’s panels support about half of the weight of the spacecraft’s crew module and launch abort system, which improves performance, saves overall weight and maximizes Orion’s size and capability.

“The fairing separation is one of our very first critical events,” said Mike Hawes, Lockheed Martin Orion vice president and program manager. “If it doesn’t work as planned, it’s probable the mission cannot continue, and tests like this help ensure it will work right the first time and every time.”

Several minutes into flight, when the panels no longer are needed, they are jettisoned using a series of pyrotechnic devices that must fire in precise sequence to move the panels away from the spacecraft and allow it to continue its mission.

“Fairing panel separation is one of the first big milestones the Orion spacecraft has to achieve as we start a mission,” said Stu McClung, an Orion engineer who managers many of the spacecraft’s pyrotechnic mechanisms. “They’re a critical part of helping Orion get to space, but once they’ve done their job, it’s essential that we get rid of them so Orion can continue on and explore deep space destinations.”

To support deep space missions, the Orion program has reduced the spacecraft’s mass by more than 4,200 pounds through several manufacturing, design and architecture changes. These efforts change the loads, or forces, that are transmitted into the fairings. Engineers have changed some of the attachment schemes on the fairing panels, including where and how the hinges and springs used to jettison the fairing panels are located.

A test in June examined how a single fairing panel separated during a normal ascent scenario and how the separation moved energy to the rest of the structure. A second test completed July 29 evaluated the separation when a 10-millisecond lag was incorporated into the pyrotechnic firing sequence. Both tests were conducted at Lockheed Martin’s test facility in Sunnyvale, California. Initial data show the panels separated as planned in both tests.

“To the outside observer, the tests don’t look different than the ones we did ahead of Orion’s flight test last year, but we’ve making modifications as part of lessons learned during that flight that will give us a better approach in the long run,” said McClung.

The tests also mimicked higher forces on the panels than they experienced during Orion’s Exploration Flight Test-1 since the spacecraft will endure different pressure atop SLS than it did atop the Delta IV Heavy rocket that sent it on its maiden voyage to space. They also evaluated a new design of a cover for Orion’s star tracker, which is used for navigational purposes.

“We’ve got a lot of component-level tests happening across the country this year to help us refine Orion’s design,” said McClung. “It’s all helping us improve the spacecraft and get it ready for astronauts.”

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