BATTELLE DETECTION SYSTEM BLOWS THE WHISTLE ON SPACE DEBRIS
November 10, 1992
RICHLAND, Wash. –
While a pebble may simply chip a car's windshield as it's kicked off the roadway, space debris even a fraction of that size may create a more serious hazard to a spacecraft as it travels through space.
To address this concern, researchers at PNNL are developing special detection systems to spot punctures from micrometeoroids and other space debris or leaks in the seals of the U.S. Space Station Freedom. Battelle is performing the work for The Boeing Company, Huntsville, Alabama, — prime contractor to NASA for development of the space station modules.
"In the space station it will be critical to locate and repair leaks and punctures within minutes to reduce the loss of valuable air supplies," said Wayne Lechelt, Battelle's project manager. "Air reserves will be limited as additional air supplies must be transported to the station by the space shuttle. No more than four and one-half pounds of air a day can leak from the station without posing an operational problem."
The station will be a multipurpose scientific center, permanently staffed by NASA astronauts and visiting international astronauts from Japan and Europe. Deployment is scheduled to begin in the mid-to-late 1990s, with full operation planned early in the year 2000.
Through the Boeing-Huntsville contract, Battelle is developing full- scale, functional leak detection prototypes for final testing by Boeing and will assist in writing the specifications for final production. Previously, Battelle completed feasibility studies on the system through its role as operator of the Pacific Northwest Laboratory for the U.S. Department of Energy.
To locate seal leaks, a sensor system is being developed at Battelle which will detect a loss of air pressure in the monitored area. The pressure sensors will be located in the space cavities between all three-paned windows and along the seals in hatches and berthing rings throughout the space station.
"Since several hundred feet of seals will be used in the space station, it is inevitable that slow leaks of minute quantities of air will occur in some of the seals," said Chester Shepard, developer of the pressure sensor component. "The pressure sensors will provide continual air pressure readings and alert station managers to any significant air loss so leaking seals can be repaired before they become a threat."
The second component consists of a network of acoustic sensors on the body of the space station to detect sound waves caused by impacts or punctures from micrometeoroids and other space debris.
"Through the use of sound waves, the acoustic emission monitoring system will detect any impacts to the station and then monitor the area for damage," said Mark Friesel, developer of the acoustic system. "We've taken a proven technology used for more than a decade in the nuclear industry to identify cracks in pressure vessels and adapted it for use on the space station."
Weight and size are critical factors in determining the type of leak detection system that economically can be transported into space.
"The cost to transport materials into space is estimated at $5,000 a pound, so it is essential to use a compact detection system weighing only 10 to 20 pounds," said Douglas Lemon, initiator of the Battelle project.
"Therefore, the final system will be miniaturized for space use, resulting in more than a 50 percent decrease in size, weight and power consumption compared with similar systems used on earth."
The final detection system will be highly energy efficient as the entire space station is designed to function on minimal energy -- comparable to the electrical power required to operate approximately 70 microwave ovens. In addition to providing data for use in developing a space station detection system, Battelle researchers believe the miniature detection systems could be adapted for use in new safety enhancement technologies for military and civilian aircraft.