MAE 435
Fall 2013
Sahil Dhali
Christopher Quarles
Michael Foch
Brockton Baskette
Kyle Wade
Cian Branco
Advisor: Dr. Robert Ash, P.E.
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Space debris are a serious hazard to
continued Space exploration
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Dead CubeSats are hard to track
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De-Orbit Device Project aimed at Prototype
for 1U CubeSats
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De-orbit Device Project is multidepartment
effort between the Mechanical and Electrical
Engineering Departments
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MAE 435 Group’s goal to build the prototype
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Sublimation at room temperature
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Sounding Rocket Altitude: 160kms.
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Pressure for sublimation@160kms: 1.42*10-6
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Temperature for sublimation@160kms: -41’C
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Unknown leak in large vacuum chamber
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Extensive man hours spent troubleshooting
and brainstorming solutions
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Ultimately had to resort to using small
vacuum chamber
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The small chamber reaches minimum
pressure around 3 minutes
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Design required to fit inside small chamber at
minimal cost
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Prototype: Steel wire wound around itself in
the shape of a Fermat’s Spiral.
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Operates on 4 AA batteries.
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The element can achieve temperatures between 60’C to 85’C
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The spiral grill was designed to create a flat surface area with as much
contact with the plate holding the benzoic acid.
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Materials readily available
Inexpensive
Easy to modify design
Difficult to control heat output
Power runs out quickly
Requires Direct Contact
• Default temperature:65-80 ‘C
• Potentially can go up to 180’C
with appropriate voltage.
• Made of 4 major parts:
• The LED light cover
• The lithium battery
• The Atomizer (heating
element)
• The mouth piece
• Fig 1 shows the mouth of the piece where the
airbrake would be attached with the epoxy.
• Fig 2 shows the top view of the heating
element. The benzoic acid crystal would be
secured on the screen over the heating coil.
• Fig 3 shows the battery pack we used to perform
the experiment. It attches to the bottom of the
element and powers to heat the coil visible in
fig.2.
Fig 3
Fig 1
Fig 2
Extremely light weight; usually Al alloy;…..
Weight Constraint: Check
 Safe and easy to use and store;…..
Storing and lasting Constraint: Check
 Power efficient; Works on a 3.1V – 6.7V to achieve max
heating capabilities;…..
Power Constraint: Check
 Size is significantly smaller than previous design, but needs
to be more compact…..
Space Constraint: Not Check
 Bowl on which acid to be secured cannot hold all the acid
required for complete deployment…..
Container Volume Constraint: Not Check
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Meets our temperature requirements, which
was our main concern.
The on board lithium battery should be
enough to power our heater.
This device is powered by a button which has
to be manually pressed
Now all that is needed for the heating
element is a bigger bowl to store the
complete amount of the acid, securing it in
the mylar.
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Design remote activation for heating element
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Fit all the parts together for one final test
before launch.
Operates mission specific transceivers,
antennas, transmission lines, amplifiers
and digital signal processing.
 Intended to communicate with orbiting
weather satellites and amateur radios to
obtain earth images and current
prevailing weather conditions.
 Designed to receive data from NOAA
weather satellites.
 OUR PURPOSE: Use the SGS to keep
constant communication with our
CubeSat to obtain its position coordinates
and signal to deploy the airbrake on
command.
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Material - Aluminized Mylar for its strength
and reflectivity. (DuPont Films)
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Target Cross-sectional area – 1 m2
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The inflation medium will be benzoic acid.
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Benzoic Acid Pressure
 Pmin > 0.1813 Pa (greater than environment @ 90 km)
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Partial Pressure of Air
 Ambient air in balloon is to be removed to prevent
premature inflation
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Benzoic Acid Placement
 Must absorb enough heat from heating element to
reach sublimation
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New material from (Coated Product Sales)
was ideal for sealing.
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Rectangular Cross-Section (Pillow shape) was
used.
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Cross-sectional area may need to be reduced
due to chamber volume.
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Benzoic acid stored in a washer with a screen.
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Epoxied (cold welded) to inflatable.
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Located on the inner surface of balloon.
 Vacuum Seal-Off Fitting – Oerlikon Leybold
product
▪ Predesigned to seal off during vacuuming, solid heat
conduction, low weight and small profile
▪ Vacuum seal-off fitting was press-fit into the bottom of
chamber
▪ Balloon will be epoxy sealed to the fitting
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During removal of ambient air, the material
was sucked into the valve exhaust creating a
seal.
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Did not allow for all ambient air to be
evacuated.
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Solutions included folding the balloon before
pumping, a pump with a throttle and/or
collapsible stent.
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Provides a pressurized zone to house the
balloon.
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Contains a valve mounted in the bottom
surface.
 Current prototype does not account for camera
mounting
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Single layer of
Kapton failed.
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Punctured by
sharp corners of
chamber cap
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5 mil Mylar holds
pressure with 2
gaskets
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There are multiple
points of
deformation in
membrane
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Mounting doors on pins
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Locking mechanism to keep the doors closed
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Prototype in current state reduces chance for waste
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Overall Goal to pass working prototype to current
434 students at end of the semester has been met
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Hand-off to occur next week
Questions? Comments? Concerns?
Thank you!