June 7, 2013
Orion Module Gets Thumbs-Up After Month Of Stress Tests
redOrbit Staff & Wire Reports - Your Universe Online
The module, which is scheduled to launch as part of Exploration Flight Test-1 (EFT-1) in September 2014, will travel farther from Earth than any spacecraft built for human use in over four decades. Orion will fly approximately 3,600 miles above the planet´s surface and will return at speeds of approximately 25,000 mph.
During the test flight, it will undergo “an array of stresses, or loads, including launch and reentry, the vacuum of space and several dynamic events that will jettison hardware away from the spacecraft and deploy parachutes,” NASA explained. In order to prepare the module for those rigors, engineers at the Kennedy Space Center in Florida have been running it through a series of different tests to ensure its safety and effectiveness.
The engineers constructed a 20-foot-tall static loads test fixture for Orion. The fixture includes hydraulic cylinders which push or pull on the module depending on the type of load being simulated at any given time.
The apparatus produced 110 percent of the load caused by eight different types of stresses that the vehicle will experience during EFT-1. The loads ranged from 14,000 pounds to 240,000 pounds, and the module´s responses were measured using over 1,600 strain gauges, the space agency said.
“The static loads campaign is our best method of testing to verify what works on paper will work in space,” said Charlie Lundquist, NASA's Orion crew and service module manager at Houston´s Johnson Space Center. “This is how we validate our design.”
In addition to simulating a variety of different loads, the engineers also pressurized the crew module in order to simulate the effect of the vacuum in space. This simulation allowed them to make sure that it would remain pressurized under those conditions, while also verifying that repairs made to superficial cracks in Orion´s rear bulkhead caused by previous pressure testing had been done correctly.
That prior test, which took place in November, “revealed insufficient margin in an area of the bulkhead that was unable to withstand the stress of pressurization,” NASA said. “Armed with data from that test, engineers were able to reinforce the design to ensure structural integrity and validate the fix during this week's test.”
“To repair the cracks, engineers designed brackets that spread the stress of being pressurized to other areas of the module that are structurally stronger,” they added. The capsule was “successfully pressurized to 110 percent” of the conditions it will experience in space, NASA said, “demonstrating it is capable of performing as necessary” during the EFT-1 experimental flight in November of next year.