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IBEX November 2007
From Dave McComas, IBEX Principal Investigator
IBEX PI Dave McComas
October was filled with "integration" of the IBEX payload and spacecraft. During this activity we electrically and mechanically assemble the pieces and run the spacecraft and payload software to make sure that everything works well together properly. The picture shows integration testing in the clean room with the spacecraft side panels (left and right), which hold the IBEX Hi and Lo sensors, connected to the rest of the spacecraft (center) via jumper cables.
Spacecraft integration and testing
One of the big milestones is to get through a first Comprehensive Performance Test (CPT) that tests the functionality of essentially all parts of the flight system. During the first running of the CPT there are myriad small (but important) issues that arise - each and every one of them needs to be "run to ground" to make sure that we will not have any problems operating our spacecraft on orbit. The person responsible for leading the integration is Tim Wiegand from Orbital Sciences, the IBEX Integration and Test (I&T) Lead. Tim is a seasoned I&T veteran and it's great to have his steady hand at the wheel for this very complicated, and sometimes nerve-wracking, process.
Tim Wiegand
By Christine Minerva, Adler Planetarium Educator
Tim Wiegand, IBEX Integration and Test Lead
As the Integration and Test Manager for the IBEX mission to explore the boundary of the Solar System, Tim Wiegand makes sure that a team of scientists, engineers and technicians correctly assemble the IBEX spacecraft from parts built all over the world, test it to see that it works, and finally, install it on the rocket that will launch it into orbit around the Earth.
Tim compares his job as an integration and test manager to supervising a construction project. "I always think of integration and test management as building a house or a building. There are all these specialists who know how to put in bricks and wires, but you have to put everything together in the right order, and make sure that everything is done properly, and you have to show proof that it's been done," he said.
Working in integration and testing is a challenging but exciting job. "One of the best parts of my job is being able to identify a problem, troubleshoot it and then fix it. Launch operations are also very exciting. We get to go to launch site, put the satellite on the rocket, and experience the excitement of the final countdown and launch. That's the final payoff," Tim said.
In June 2008, Tim expects to travel to the Kwajalein Atoll in the Marshall Islands to monitor the spacecraft as it launches from a Pegasus rocket, which is first flown on an airplane. "I have been involved in other Pegasus missions, and it is always quite a thrill watching the Pegasus rocket drop off the airplane, hoping it will light," Tim said.
This month, Tim and his team at Orbital Sciences are helping the IBEX mission get one step closer to launch by integrating the IBEX-Hi and IBEX-Lo sensors into the spacecraft "bus," or main body. The sensors will detect high-energy neutral atoms to help make a map of the boundary of the Solar System.
Attaching the instruments to the spacecraft bus involves an intense series of pre-tests and "comprehensive performance tests" to make sure that the instruments work properly on their own and also work together with the rest of the spacecraft once they are attached to the bus. In addition, Tim plans and supervises tests to figure out if the spacecraft will function in an environment that simulates the vacuum and temperature of space, as well as the intense vibrations that will rock the satellite as it is launched into orbit. "We do tests throughout the program to verify that [the spacecraft] is still working," Tim said.
Growing up in a small town in southeastern Pennsylvania, Tim knew since high school that he wanted to be an engineer. "I was always good at math and science. I also liked electronic gadgets, and was really interested in figuring out how these gadgets worked," he said. He attended Drexel University, graduating with a degree in electrical engineering, and later received a Master of Science in Electrical Engineering from the University of Southern California.
As a teenager, the electronics of military aircraft also fascinated Tim. "I was interested in the military side of avionics and the devices used in airplanes for sensing and countermeasures, stuff like that," he said. In college, Tim joined a program that is similar to the ROTC for the Air Force in order to finance his education. As a result, he served for five years in the Air Force, attaining the rank of captain.
It wasn't until he was assigned to work on rockets and satellites at Los Angeles Air Force Base that Tim considered aerospace engineering as a career. "After leaving the military, I ended up getting a job as a spacecraft test engineer, which was similar to what I was doing for the Air Force. In the next few years, I became an integration and test manager, which means you're managing the various people that put the satellite together. Working in integration and test is not something you plan for. I was always planning to be an engineer, but I probably would not have ended up here at Orbital in my current job if it weren't for my initial assignment in the Air Force, where I was able to work on various rocket programs," he said.
Although Tim has two engineering degrees, it was his work experience that prepared him to excel at integration and testing. "This kind of job is more of an on-the-job training type of thing," he said. "There is no specific college class you would take to get here. A lot of it is common sense and experience. In this job, you may work 5-10 years as a test engineer before you become the manager because you need to gain some 'hands-on' experience, and that's generally on-the-job training, nothing you can really learn from a textbook."
In fact, Tim said that a skilled technician can achieve a job as a manager in integration and testing. "We probably have people working as integration and test managers who have no college background - they are just good technicians or managers with a lot of experience," he said.
Tim believes that the stereotype of NASA engineers as geniuses is exaggerated, especially in his field. He said, "Working on a NASA mission is not as complex as you think it is. While there are some pretty smart people involved, there are a lot of regular type people, too. You don't have to be the stellar student to get there. [In integration and testing], in fact, you really don't want a perfectionist type person - you have to deal with time and money constraints, and you may want to - or have to - go with what's good enough."
Tim recommends integration and test management to people who like putting things together, and participating in the entire design cycle of a space mission, including launching the spacecraft and monitoring the spacecraft while in orbit. Tim also recommends the Air Force as a good entry point for this type of engineering "because it gives you good exposure to the aerospace industry. I felt that if I'd never joined the Air Force, I never would have gone into this field - something else would have come along," he said.
More than anything, Tim loves working on small science missions like IBEX that help increase human knowledge, and offer opportunities to work with a small team of people on a large array of tasks. "On a small mission, everyone is doing many different jobs, so you don't have to just focus on one small part of the satellite," he said.
Contributing to many parts of the mission is very rewarding, although it does not leave Tim much time to pursue his hobbies. "I'm a self-taught guitarist, and when I have time, I strum on the acoustic guitar or the electric bass," he said.
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