MAE 435 Fall 2013

Sahil DhaliChristopher Quarles Michael Foch Brockton Baskette Kyle Wade Cian Branco Advisor: Dr. Robert Ash, P.E.

 Space debris are a serious hazard to continued Space exploration  Dead CubeSats are hard to track  De-Orbit Device Project aimed at Prototype for 1U CubeSats

 De-orbit Device Project is multidepartment effort between the Mechanical and Electrical Engineering Departments  MAE 435 Group’s goal to build the prototype

 Sublimation at room temperature

 Sounding Rocket Altitude: 160kms.  Pressure for 1.42*10 -6  Temperature for -41’C

 Unknown leak in large vacuum chamber  Extensive man hours spent troubleshooting and brainstorming solutions  Ultimately had to resort to using small vacuum chamber

 The small chamber reaches minimum pressure around 3 minutes

 Design required to fit inside small chamber at minimal cost  Prototype: Steel wire wound around itself in the shape of a Fermat’s Spiral.  Operates on 4 AA batteries.

 The element can achieve temperatures between 60’C to 85’C  The spiral grill was designed to create a flat surface area with as much contact with the plate holding the benzoic acid.

 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 Fig 2Fig 3 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.

 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

 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.

 Design remote activation for heating element  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.

 Material - Aluminized Mylar for its strength and reflectivity. (DuPont Films)  Target Cross-sectional area – 1 m 2  The inflation medium will be benzoic acid.

 Benzoic Acid Pressure  P min > Pa (greater than 90 km)  Partial Pressure of Air  Ambient air in balloon is to be removed to prevent premature inflation  Benzoic Acid Placement  Must absorb enough heat from heating element to reach sublimation

 New material from (Coated Product Sales) was ideal for sealing.  Rectangular Cross-Section (Pillow shape) was used.  Cross-sectional area may need to be reduced due to chamber volume.

 Benzoic acid stored in a washer with a screen.  Epoxied (cold welded) to inflatable.  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

 During removal of ambient air, the material was sucked into the valve exhaust creating a seal.  Did not allow for all ambient air to be evacuated.  Solutions included folding the balloon before pumping, a pump with a throttle and/or collapsible stent.

 Provides a pressurized zone to house the balloon.  Contains a valve mounted in the bottom surface.  Current prototype does not account for camera mounting

 Single layer of Kapton failed.  Punctured by sharp corners of chamber cap

 5 mil Mylar holds pressure with 2 gaskets  There are multiple points of deformation in membrane

 Mounting doors on pins  Locking mechanism to keep the doors closed

 Prototype in current state reduces chance for waste  Overall Goal to pass working prototype to current 434 students at end of the semester has been met  Hand-off to occur next week

Questions? Comments? Concerns? Thank you!