An Ordinary Week in the Career of an Aeroacoustics Engineer
Stephen M. Jaeger
Monday, November 17, 1997:
8:00 a.m.: I arrive at work, turn on my computer
and make coffee. Nothing works at NASA without a computer or coffee. The
first 30 minutes of the morning is spent reading and answering E-mail
and phone messages.
9:00 a.m.: I attend an engineering class televised from Stanford
University. This is very convenient for engineers at NASA. We can go to
school by watching the class live over the television rather than having
to drive all the way to campus. I have been going to this class three
times a week for two months.
10:30 a.m.: I sit in on a presentation by Dr. Vern Rossow. Vern
Rossow is the senior scientist in our branch. Engineers are always presenting
their ideas to their co-workers. We in turn ask questions about his findings
and discuss the conclusions of his work. We also point out any problems
he may have overlooked, but we're usually very nice about it.
Lunch time: I go for a run around NASA and work out at the gym.
Since I might be sitting around all day in front of the computer, it's
nice to get out and get some exercise.
1:00 p.m.: I finish writing up a data file for our array processing
software. This data file includes information on the 100 microphones we
have installed in our microphone array. The array is an aluminum wall
with microphones mounted in a special pattern somewhat like the arms of
an octopus. The wall will be mounted inside a wind tunnel. The array allows
us to "see" sound. We can point the array at a model in a wind tunnel
and make color pictures of the sound. This allows us to pinpoint the areas
on the airplane model that make the most noise.
5:00 p.m.: I finish the day by writing a brief report for my company
telling them what work I have been doing for the last couple of weeks.
Since my company is providing services for NASA, it is important that
they know the type of work that their employees are doing for their customers.
6:00 p.m.: Off to karate class.
Tuesday, November 18, 1997:
8:00 a.m.: I arrive at work and go immediately
to watch another class over the television.
10:00 a.m.: I make coffee of course and then I spend most of the
day collecting information for another engineer, Dr. Dale Ashby. His project
is to prepare for a wind tunnel test in 1999. In this test, a very large
model of a jet liner will be placed in the 40- by 80-Foot Wind Tunnel.
This wind tunnel is one of the largest in the world. The airplane model
is almost 60 feet long so the wind tunnel has to be big. During this test
we will be using the microphone array to measure the noise that the airplane's
wings make during landing. This is very important because as jet liners
get larger and their engines get quieter, the noise created by the wings,
flaps and landing gear becomes more significant.
My job is to give Dale all the information he needs
to measure the noise of the model including a list of equipment we need,
what type of noise measurements we want to make and who will be helping
out with the test. Often the planning and preparation for a wind tunnel
test can take three or four years.
Lunchtime: I play volleyball with some friends at lunch. I'm setting
the ball much better but I still need to work on my overhand serves.
3:00 p.m.: I help out with setting up the microphone array in our
lab. I have spent most of the last year helping to design the array. Now
that the array has been built, I have been spending a lot of time installing
the microphones in the aluminum plate and making sure everything works.
Wednesday, November 19, 1997:
8:00 a.m.: Remember: NOTHING works at NASA
without a computer or coffee.
9:00 a.m.: Off to class.
10:00 a.m.: Cool news! I received my first patent. A patent is
one of the great milestones of an engineer's career. The patent, which
I share with three other people, is for an invention that can reduce noise
when microphones are used in a wind tunnel.
11:00 a.m.: I am called away to help troubleshoot some difficulties
with the array setup. Nothing ever goes as planned and complicated pieces
of equipment like the microphone array have a lot of electronic parts
that don't always work like they are supposed to.
I set up a speaker to test the array. The speaker
can really crank because we are using a 300 Watt stereo amplifier, but
for this type of test that kind of noise will not be necessary. I also
designed a round aluminum horn to connect with the speaker and provide
a uniform sound source.
2:00 p.m.: I continue working to provide information for Dale's
6:00 p.m.: I spend most of the rest of the evening writing a newsletter
for the AIAA. That's the American Institute of Aeronautics and Astronautics.
A "friend" of mine volunteered me for the job of Newsletter Editor. This
task usually takes a few hours each month but it's a chance to write articles,
create artwork, and support my profession.
Thursday, November 20, 1997:
8:00 a.m.: Off to class.
10:00 a.m.: I gather with the other members of our microphone
array team for our weekly meeting. At this meeting we discuss how the
project is progressing. A complex project like the microphone array requires
a team effort and the meeting is a great way to get advice and ideas from
the other team members.
11:30 a.m.: I take time out for a long run around the base. Most
of us at NASA get some kind of exercise at lunch. It might be soccer,
rollerblading, hockey, aerobics, running, cycling or weight-lifting. After
a good workout, I can eat my lunch at my desk while I work.
1:00 p.m.: I spend the rest of the day working on Dale's project
and I prepare for a future meeting where we will discuss the noise measurements
we need to do for Dale's test. This work includes making detailed computer
drawings of test setups, making a list of required equipment and composing
a list of measurements. I enjoy taking an idea and creating a detailed
drawing on the computer. Even more exciting is seeing that drawing turned
into reality. We have many tools and instruments at NASA designed for
very special purposes including speakers, microphones and models. Many
of those tools started out as an image on my computer screen.
6:30 p.m.: I attend an AIAA dinner meeting. The AIAA has a meeting
every month, where engineers and scientists talk about everything from
designing airplanes to the exploration of Mars. This night's speaker,
Dr. Michael Drory, gave an interesting talk on using artificial diamonds
for aerospace applications.
Friday, November 21, 1997:
8:00 a.m.: I make coffee. We are running out
of coffee and it's probably my turn to buy more. This is a critical situation.
9:00 a.m.: I attend the televised class. The final exam is only
two weeks away. I hope to do well.
10:00 a.m.: I'm getting back to a project I had put off for awhile.
Sometimes I have to juggle projects according to their priority. A task
that may have seemed important yesterday may have to be put on the back
burner when a more urgent opportunity appears.
This project is a computer code that we will use
to record and process the noise from a starter pistol. We will use the
starter pistol, which fires blanks, to calibrate the 40- by 80-Foot Wind
Tunnel after the modification of its test section is complete. The wind
tunnel test section has been lined with acoustic fiberglass to eliminate
echoes. We will fire the pistol and use the computer code to record any
echoes. We also have a small cannon we can use. It is very loud in the
test section and a lot of fun to fire off!
4:00 p.m.: I help with testing the microphone array. We are preparing
for a demonstration of the array next week. It should work nicely.