The Isothermal Dendritic Growth Experiment (IDGE) flew aboard
the space shuttle Columbia (STS-87). During the 16-day mission, launched
on November 19, 1997, the experiment was monitored
and controlled from ground facilities at NASA's Lewis Research Center and
the Rensselaer campus.
While our analysis is still continuing, we have made some very interesting
observations already. For example, it appears that dendrites have
a much more complicated interaction with the surrounding thermal environment
than was realized. Video images obtained during the flight experiments
show that two dendrites growing close to one another, slow down relative
to single, isolated dendrites. Results from our experiments on earlier
space flights have tested various theoretical models which are in turn
being used in more industrial applications such as computer programs used
in casting. The most recent experiments offer data that can be used
for testing such theories for the case of a different material, pivalic
acid.
To accommodate the community interest in the experiment
and the related shuttle mission operations, a Visitor's Room was
set up on the Rensselaer campus. The experiment telemetry (data) received
from the shuttle and the NASA control centers was displayed on video and
computer monitors in the Visitor's Room. In addition, there was a wide
assortment of posters, models, demonstrations (including a drop tower producing
0.6 seconds of microgravity), and presentations about space flight, microgravity
science, and materials science. Many of these exhibits were
constructed by RPI students and local primary and secondary school classes.
| The
first two IDGE flight experiments (STS-62
& STS-75)
used a material called Succinonitrile.
The third
flight (STS-87)
used a material called Pivalic Acid.
Both of these materials solidify like metals do, except they are transparent! |
On school days during the shuttle mission, the
Visitor's Room was used by class groups from many local primary and secondary
schools. These visits included a 15 - 20 minute presentation about materials
science and microgravity, after which individuals may explore the exhibits
at their own pace, and ask questions of the IDGE representatives.
In addition to the visitor center, during
the mission, a series of public lectures were given featuring talks about
the MIR space station, the benefits of space research, and the space shuttle.
NASA astronaut, and scientist Albert Sacco even gave a presentation of
his experiences aboard the shuttle, where he conducted his own set of crystal
growth experiments!
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Teacher
Training
During the summer of 1997, a two week program called the Microgravity
Summer Institute, was conducted at Rensselaer. Approximately two dozen
local primary and secondary school teachers attended space-related presentations
for the first week and in groups, applied this material to develop lesson
plans for classroom use during the second week. As part of this program,
one of the teacher groups decided to construct a drop
tower, which is a device that gives a controlled way of working with
the phenomena of free-fall, where gravity is not "experienced". This drop
tower produces about 0.6 seconds of free fall, during which an experiment
can be performed and recorded using the on-board video camera. The video
tape is then played back to study what happened in more detail. |
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