A Copper Alliance Member
Edition #5
Copper Heaters Improve Fuel Tank Safety on Space Shuttle
The Space Shuttle Discovery awaits launch for its Return to Flight mission. Copper heating elements are used in several key locations on the shuttle's exterior as part of a series of safety enhancements NASA implemented following the Columbia accident.Photo Courtesy of NASA/KSC.
High-resolution version of this photo.
When the Space Shuttle flies again this July – for the first time since the Columbia disaster two years ago – copper will be an important part of two new safety features designed to prevent future accidents.
The stakes are high: All seven Columbia crewmembers died in 2003 when their ship exploded on its return to Earth. Investigators believe the accident was caused by a suitcase-sized piece of exterior foam insulation that broke off from the Exterior Tank (ET) during launch and punctured the shuttle's left wing. Upon re-entry to earth, superheated gases penetrated the wing, causing the shuttle to disintegrate.
Re-evaluating the ET's thermal protection system, which prevents ice and frost from forming on its metal surface prior to launch, was a priority for NASA engineers following Columbia. Frozen condensation could, like the foam, fall off and damage the shuttle's heat-deflecting ceramic tiled exterior during take-off.
One of the new safety measures NASA has implemented for the launch of Discovery this month is the replacement of two foam sections on the shuttle where the ET connects to the spaceship. It was this area where foam broke loose from Columbia and a previous shuttle voyager, Atlantis.
Artist concept of the modified External Tank which will fly during STS-114, the Space Shuttle's Return to Flight mission. Illustration Courtesy of Lockheed Martin/NASA Michoud.High-resolution version of this photo.
Copper Plates for Heaters
Instead of foam, NASA is using electric heaters installed under key components known as bipod fittings. Four 300-watt cartridge heaters are each placed on a copper plate that is separated from the ET by thermal padding. Copper's superior heat-transfer properties will help distribute the heat to this vital area and prevent ice from forming on the fittings. According to NASA, the heaters will melt any ice formed by condensation from the tank's super-cold cargo – 526,126 gallons of liquid propellant used to fire the shuttle's three main engines.
After extensive testing in wind, vibration, structural, and thermal trials, the bipod heaters are being retrofitted to the shuttle fuel tanks for this and all future space missions. NASA will continue to spray the rest of the fuel tank with insulating foam to keep its contents in their liquid state and to prevent icing.
 High-resolution version of this photo. |
 High-resolution version of this photo. |
A close-up of the redesigned bipod fitting that helps attach the External Tank to the shuttle. The old design, left, used a foam ramp to prevent ice from building up on the fitting. Falling foam opened a hole in one of Columbia's wings, leading to the orbiter's breakup on entry. The new design, uses a copper heating element instead of foam to prevent ice buildup. Illustration Courtesy of Lockheed Martin/NASA Michoud.
Copper Heating Belts
Copper is also being used for a belt-like heater for the uppermost bellows (a flexible joint) of the Liquid Oxygen Feedline. This section needs extra protection because it is positioned above the shuttle, and frozen debris falling from it would likely strike the ship. The bellows heater consists of two copper- nickel metal strips about 53 inches long and one-half inch wide.
The fastest growing area for copper tubing, however, is for fuel gas. More home builders are installing gas these days, says Rick Schaffer, a representative for Mobile GaThe External Tank is the largest piece of equipment on the shuttle, measuring 15 stories high and weighing over 1.5 million pounds. When the shuttle reaches its optimal velocity, the ET (like the two rocket boosters that fire the vessel into orbit) is jettisoned and falls back to earth. Cu
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NASA Return to Flight Mission
Copper Comet Impactor: A NASA Success Story
This spectacular image of comet Tempel 1 was taken 67 seconds after it obliterated Deep Impact's copper- topped impactor causing the bright splash of light seen here. The photo, taken by the mission's flyby spacecraft, gave NASA scientists a great look at the comet's surface, including ridges, scalloped edges and possibly impact craters formed long ago. Photo Courtecy of NASA/JPL-Caltech/UMD.High-resolution version of this photo.
More than fireworks exploded in the sky this Fourth of July. While most Americans enjoyed local parades, backyard barbecues and the company of friends, NASA was busy blasting a hole deep into a comet far out in space. The goal of the mission: To uncover valuable information about the nature and origins of Earth's solar system.
One of mankind's oldest metals played an integral part in this one-of-a-kind interplanetary pyrotechnics display. NASA scientists deployed a copper-topped probe called a "smart impactor" in a deliberate head-on collision with Comet Tempel 1 that occurred in the early hours of July 4.
NASA's Deep Impact mission was hailed as a dazzling success as more than 50 telescopes and 200 researchers around the world watched when the comet – traveling faster than a speeding bullet at 23,000 miles per hour – collided with the probe.
As planned, the impactor's rounded copper front-end struck the comet's nucleus on the side illuminated by the sun, causing a crater to form on the surface and dust, gas and other emissions to spew forth like a volcanic eruption. The explosion, equivalent to detonating five tons of dynamite, vaporized the impactor but did not drastically alter the trajectory of the Manhattan-sized comet.
Why Copper?
Copper, which made up half of the impactor's total mass, was selected for this mission based on several key factors, including the hardness of the metal. To make the probe even stronger, the copper was fortified with three percent beryllium.
But it was copper's molecular structure that made it ideally suited to gather data from the emissions that spewed forth from the comet after the collision. Because copper's atomic structure reacts slowly with other elements – particularly the oxygen found in cometary water – burning copper emissions did not obscure spectroscopic images taken during the crash. Other materials, such as aluminum, would have created distracting emissions and limited the effectiveness of the instrument used to monitor light reflecting from the comet.
 Technicians inspect copper-topped Deep Impact impactor. Image Courtesy of Ball Aerospace & Technologies Corp. High-resolution version of this photo. |
Images taken by the monitoring equipment were transmitted from the spacecraft via X-band communication. They can be viewed on NASA’s Deep Impact Web site.
Comets are almost as old as Earth and our neighboring planets. Scientists believe they are made of ice, gases, rocks and dust leftover from the formation of our solar system some 4.6 billion years ago.
 Dr. Michael F. A'Hearn, University of Maryland astronomer, with the Deep Impact copper cratering mass. Image Courtesy of Ball Aerospace & Technologies Corp. High-resolution version of this photo. |
"The last 24 hours of the impactor's life should provide the most spectacular data in the history of cometary science," said Michael A'Hearn, the Deep Impact Principal Investigator. "With the information we receive after the impact, it will be a whole new ballgame. We know so little about the structure of cometary nuclei that almost every moment we expect to learn something new."
Discovered over 10,000 years ago on earth, copper is prized for its beauty, strength, durability and ability to be combined or "alloyed" with other metals to create new metals like brass and bronze. In its pure or alloyed form, copper is an indispensable material used by NASA, the U.S. military and manufacturers in various industries including: appliances, computer technology, mobile phones, wind and solar energy, plumbing tube, building construction and interior design. Cu
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NASA Deep Impact Mission Back to TopResources
