and began my
discussion with
BalloonSats — the tool
these teachers would
use to explore near
space. This included
the BalloonSat
materials, procedures,
and limitations. In the
realm of materials, I
gave each teacher a
set of avionics that
included a flight
computer (a
BalloonSat Mini),
digital camera, and a
choice of sensor array
(two temperature
sensors or a
temperature and
relative humidity sensor). With their
avionics in hand, teachers selected
specific mission goals and began the
paper design of their BalloonSat and
the BalloonSat constellation we
would assemble for this mission.
What constraints did these
teachers design around? For one,
there was a weight limitation: No
BalloonSat could be greater than one
pound in mass. Second, the
BalloonSats needed to include four
plastic tubes for tethering to each
other and to the rest of the near
spacecraft. Another one was the
access hatch of each BalloonSat; it
had to be placed on the side of the
BalloonSat and not on its top or
bottom. Finally, each BalloonSat had
to secure its hatch using two rubber
bands. This way, an errant battery
couldn’t slip out of the airframe by
pushing on the hatch like it was a
lever.
Thursday and Friday
Teachers began the construction
of their BalloonSats on Thursday and
finished them on Friday. Ms. Squires
— the instructor of the class and
soon-to-be PhD — provided the
materials and construction tools like
Styrofoam, metal straight edges,
(Menards, in this case) that’s pink
and 1/2” thick. The crumbly white
Styrofoam will work, but is more
difficult to build airframes with.
The teachers learned there are
several reasons we use Styrofoam to
build airframes, including its ability to
APPROACHING THE FINAL FRONTIER
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December 2015 47
The class completed their
paper design and defined the
near space mission by the end
of the day. This whiteboard
became a record of our plan
for building the BalloonSats the
next day.
Measure twice, cut once. Metal straight edges
and squares are important to laying out cutting lines
in Styrofoam. The more carefully students make
their lines, the less work they’ll do to patch up
their airframe.
Seven BalloonSats (two of
them were my experiments)
tethered together to the rest of
the near spacecraft. Located at
the far end are two tracking
modules, a recovery parachute,
and 18 feet of load line to attach
the balloon to the parachute. All
together, this near spacecraft
weighed about 12 pounds.
A completed BalloonSat and its initial
paper design. The white cap is the
bottom of a Styrofoam cup. It acts as
a sun shield for the BalloonSat’s
temperature and relative
humidity sensors.
