| Judging by my conversations
with peers in the industry, it is striking how many engineers
grew into their professions by tinkering with junk in
their families' garages. Objects of surprising simplicity
and utility were created by eager, inventive young minds,
from the stuff stored by can't-let-it-go-to-waste parents.
Along the way we learned and developed a passion for engineering.
And it was no big loss if a "junk" contraption didn't
Where does that creative, pioneering, seat-of-the-pants
engineer in us go as we mature?
Only rarely, it seems, does this approach survive
the "real world." For example, several years ago one
of the engineers in my organization had an interesting
idea in reaction to a problem he heard about. Several
of the International Space Station (ISS) technical communities
needed to collect various types of on-orbit data to
validate their respective math models. The necessary
instrumentation had been eliminated from the ISS Program
during previous budget-cutting exercises. To reinstate
even a tiny fraction of the originally requested instrumentation
at this late stage of the design cycle would be cost-prohibitive.
Prompted by the Loads and Dynamics community, the ISS
Prime contractor estimated alone the integration costs
to exceed $24 million for a greatly scaled-back complement
of accelerometers. Although everyone involved cringed
at the cost estimate, they knew that the traditional approach
of routing wiring, scarring the existing hardware designs
for instrument installations, and redoing the myriad drawings
and interface documents could indeed be that expensive.
Everyone, that is, save my colleague, who wondered why
nobody seemed to be considering the use of wireless technology.
He knew of a small local company that specialized in wireless
applications, and which had developed some spread-spectrum
radio technology under a NASA Small Business Innovative
Research grant. They had produced a low-cost transceiver
for him that functioned very well during a recent Shuttle
|We were assured
that, despite our budget constraints, almost anything
His idea was simple: incorporate similar technology
into small, instrumented boxes that could be velcroed
wherever needed on the ISS with a minimum of integration
effort. If the boxes were made inexpensive enough, they
could be disposable, which would allow a non-redundant
system design. If a box failed, simply pull it off and
replace it, or cluster several of them in each desired
location and remotely activate the redundant units in
turn upon failure of the active unit. The possibilities
were exciting indeed.
I was asked to lead the exploratory project to determine
the feasibility of this approach, then build a prototype
system, conduct a flight experiment, and, if appropriate,
convince the ISS Program to approve the addition of
a multipurpose instrumentation system based on this
concept. The problem was that discretionary funds were
exceedingly tight that year and my organization could
only afford a shoestring budget -- maybe $50 thousand
if I was lucky. It was an impossible undertaking in
a conventional sense; one of the instruments we were
interested in cost $23 thousand per unit!
I met with the wireless company's president, a gentleman
with an exuberant, entrepreneurial attitude, who served
to energize my "team" (a solitary veteran of the previous
flight experiment) and me. We were assured that, despite
our budget constraints, almost anything was possible.
Were it not for this company's demonstrated ability
to follow through on its claims, I would have been highly
Instead, I remembered a friend's experience. Faced
with a six-figure cost for a wave facility test to determine
which of several ISS crew-return-capsule designs would
be most seaworthy, he built his own wave tank with a
few sheets of plywood, foam rubber, some plastic sheeting,
and a scavenged wash-machine motor and mechanism. For
a couple hundred dollars, he narrowed the design options
I shifted mental gears and adopted a more can-do attitude.
Hence, our project quickly took on a garage-style
feel. Since size minimization was critical to our design
concept, we scoured the vendor ranks until we found
one that made automobile airbag accelerometers the size
of pencil erasers. By modifying the signal processing,
the mechanism could be adapted to measure the much lower
acceleration levels we were interested in. One problem
was solved -- for $50 a pop.
Similarly, we bought and modified other items until, after
a scant three months, we had two working prototype wireless
instrument boxes the size of a double-thick pack of cigarettes,
complete with accelerometers in three axes, pressure transducers,
radiometers, solar-power rechargeable battery cells, radio
transceivers, and data processors. Included in our hardware
set was a similar-sized transceiver to plug into a standard
flight laptop computer from which we controlled the system.
All this came to under $40 thousand, including a preliminary
round of vibration and thermal-vacuum testing.
|We had hardware
but no money; they had money but no hardware.
The various managers to whom we demonstrated our prototype
marveled at the real-time, dual display of acceleration,
pressure, heat flux, and temperature data marching across
the laptop screen almost as much as at the price tag.
A second generation of smaller production units was
estimated to cost $1500 per unit, and a comprehensive
ISS instrumentation system based on this technology
was priced at an order of magnitude less than the $24
million the ISS Program had choked on previously. We
were strongly encouraged to proceed with a flight experiment.
We developed the blueprints for a flight experiment
that would test the system by measuring the effects
of the Shuttle's reaction control jets as they plumed
the Russian space station Mir. Upon conducting initial
negotiations with our Russian counterparts, and with
the local Extravehicular Activity Office that would
have to design the space-walk activity necessary to
install our hardware on Mir, I developed a schedule
and budget for the flight experiment and charged the
I soon found that the ISS Program was willing to accept
my proposal for a risk-mitigation experiment to be flown
on an upcoming Shuttle-Mir mission but that I would
have to bring my own funding. Here was the Catch 22:
the ISS Program was unwilling to fund the development
of a system it had no official requirement for, and
it was unwilling to acknowledge on-orbit instrumentation
as being a requirement until a low-cost implementation
Upon looking for solutions across the agency, I learned
of a project with similar goals as ours at another NASA
center. They wanted to develop a wireless instrument
system to measure structural dynamics and had secured
science funding to develop such a system, which they
wanted to test on the ISS. It was the perfect match
-- we had hardware but no money; they had money but
no hardware. The other project's manager eagerly accepted
my proposal to combine our projects.
Upon gaining approval for this combined risk mitigation
experiment, I left it to accept another assignment,
taking with me a new attitude inspired by my experience
with garage-style engineering. Our original project,
after several incarnations, spawned several wireless
instrumentation projects that now support the Shuttle
and ISS Programs. All of them are producing more versatile
and easily integrated flight instrumentation hardware
than conventional aerospace methods allow. They're beating
convention with shorter development times and dramatically
lower development and integration costs as well.
Perhaps we should do more of our work in the garage.
- It pays to remember the let's-try-it pioneer attitude
that drew us to our profession and, likely, to our
- If a picture is worth a thousand words, a prototype
is worth a million. Prototype early and often not
only to mitigate risk, but to help management understand
the true feasibility/potential of your concept. It's
hard not to get interested in an idea when one sees
it embodied in a functional piece of hardware!
- The use of Commercial Off-the-Shelf (COTS) components,
combined with an informal quality control/configuration-management
environment, enables Faster-Better-Cheaper prototyping.
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C. Jansen is currently the Manager for Launch
On-need at Johnson Space Center in the External
Carrier's Office of the International Space Station
Program Office. Mr. Jansen began his NASA career
as a Johnson Space Center co-operative education
student in 1982 while attending Rensselaer Polytechnic
Institute, from which he obtained his Bachelor of
Science degree in Aeronautical Engineering in 1985.