ARL Employee Enjoys Two Careers
by Dave Davison, External Affairs
G. Welles Still has been leading two lives and says he enjoys and benefits from both of them.
Still is an electronics engineer turned radiation expert. He spends half of his work life with the Survivability, Lethality and Analysis Directorate of the Army Research Laboratory at the Edgewood Area of Aberdeen Proving Ground. He spends the other half working for NASA at the Goddard Space Flight Center in Greenbelt, Md.
"Both jobs are different but both complement each other," he says.
At ARL, Still is concerned with the effects of quick blasts of radiation on tanks or other vehicles that result from nuclear weapons. For the last couple of years, he has been working on Theater High Altitude Defense. He has also worked on the PATRIOT and Linebacker air defense systems.
At NASA, he concerns himself with the effects that the radiation belts that surround the earth have on orbiting spacecraft that pass through them. The radiation can have very detrimental effects on electronic components in the spacecraft, Still says. He helps NASA set radiation design standards for spacecraft by performing shielding studies on them. Spacecraft heís studied include the Vegitation Canipoy Lidar, the Geoscience Laser Altimeter Spacecraft and the Gravity Recovery and Climate experiment. He has also designed and built an energy filter box used to increase the accuracy of radiation testing on electronics. He also has characterized the radiation within Goddardís test facility. Experience working with high-energy radiation at ARL has served him at NASA, he says.
"In both the Army and NASA, weíre concerned about trying to make components survive radiation. But with the Army, the dose rate is usually very high which is what comes from a nuclear blast. So when we do radiation testing in the Army, we want it to go as quickly as possible," Still says.
This is because of a process called annealing. After being exposed to a radiation burst, certain kinds of electronics will (to some extent) naturally heal themselves over time. So, if the testers take too long to characterize the electronics between exposures, or use too low a dose rate, annealing can undo some of the damage radiation caused. This makes the tested electronic item appear harder than it really is.
"At NASA, they want to expose electronics as slowly as possible because when a spacecraft orbits the earth it gets a radiation dose very slowly," he explains.
Also, he points out, that in this case, annealing causes the electronics to fail at a higher dose than it would from the bomb. When the Army tests, it wants to avoid annealing, NASA wants their test data to include annealing. NASAís desire to obtain low dose rate data, however, causes another set of problems.
"In test facilities, a lead shield is often used to decrease the dose rate. This produces more lower energy radiation. The lower energy radiation, through a process called dose level enhancement, interacts with metals like gold in the electronics, causing some components to fail at lower dosage rates than intended. The energy filter box is designed to shield electronics from lower level radiation." Further complicating matters is that no two components are exactly the same.
"Sometimes, identical components that come off the same assembly line right next to each other will react very differently to radiation," Still adds.
Still feels that a lot of the experience heís gaining at NASA will benefit the Army. For example, he has learned to use certain NASA codes to model radiation dose which can also apply to his work for SLAD in analysis.
"I think I know more about radiation survivability of electronics than I did before and as long as the Army operates electronics and there is a chance of nuclear attack, the knowledge and experience Iíve gotten at NASA should prove useful."
Still feels fortunate to be able to work at both places. "I have a gem of a supervisor at ARL, Drew Farenwald, who has been very supportive," but Still actually got the NASA work by chance at church.
"My wife is a Christian school teacher and we went to a reception for teachers at the church," He explains, "I was walking by a group of people and overheard them talking about spacecraft. Iíve always been interested in spacecraft so I got into the conversation. It turns out that it was someone who works for NASA and he told me they were looking for someone with expertise in radiation survivability. So I got the work at NASA because my wife taught someoneís child who works at NASA. That person was interested in radiation survivability not because he was a radiation physicist, but just because his job was to put up a satellite that would survive radiation."
He believes strongly in taking advantage of opportunity and actively managing his career, all of which has been spent at ARL or its predecessors. Still began his government career at Harry Diamond Laboratories and has been working for SLAD since it formed in the early 90s.
"Opportunities (to improve your career) exist even now in this era of downsizing if you donít give up control of your career. Decide what you want to do and ask your supervisor to help you. If you make a mistake fine, if you donít make a mistake, thatís better. But either way youíre better off, I think, than saying Ďwell, they put me here, I donít like it and now I canít do anything about it.í"
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