Hy-V.1 Skin Friction Sensor Experiment Presenters: Ryan F. Johnson Mitchell Foral-Systems November 24, 2008 University of Virginia

Outline Overview Science of Sensor Special Mission Requirements Mechanical Drawings Commands and Sensors Test Plans Compliance and Shared Logistics Management Update Schedule Missing: –Subsystem Requirements –Parts list

Overview Objective: –To test a newly designed skin friction sensor fabricated by ATK –Students to gain experience in several areas of engineering by engaging in a student run sounding rocket experiment Expected findings: –Functionality of the skin friction sensor –Analytically determined skin friction matches that of the sensor –Reusability of sensor –Survivability of sensor

Science of Sensor Skin friction is a necessary element for the understanding of fluid dynamics Skin friction –The reason we fly –The reason why we can’t fly that fast The more we understand skin friction the better chance we have to design flight vehicles that can sustain high speed flight Image from NASA HYPER-X found:

Science of Sensor Sensor uses an interferometer to measure deflections that will translate into voltage outputs Interferometer –Uses two light waves that intersect at a certain point –Skin friction causes a defection of one of the reflective mirrors –Depending on their deflections, constructive and destructive interference can be measured –This measured interference will then be translated into an output voltage t

Special Mission Requirements For experiment, UVA needs atmospheric access other than the supplied static ports These ports will need to accommodate the skin friction sensors –Adapters will be designed by UVA and cleared by NASA –Will communicate with NASA over the next few weeks leading to CDR to determine the best route to accommodate sensor PRIORITY: Sensor integration will need to be water tight –Water leak will damage other instruments and void compliance agreement Any assistance from boulder in this would be greatly appreciated Flow Rocket Skin Rocket Interior Top View

Mechanical Drawings: RockSAT Can Base Sensor bases: One for Each Sensor PCM104+ Lifted Base Plate

Mechanical Drawings RockSAT Can with Integration of sensors Two sensors attached to wall

Mechanical Drawings RockSAT can integrated into rocket Skin Two sensors Two holes 2-¾” taps Need to be sealed

Mechanical Drawings Possibilities for sensor integration 1.Tap holes Can seal holes with rubber sealing to prevent leaks Would need to drill more holes to bolt sensors to wall Use a skin mount Mounts into a window located on the outer wall of the rocket Less holes in skin Integration into rocket easier

Future Analysis Center of mass Use Cosmos to create G-Loads on payload Tests material selection and design Look into water tight sealing Using rubber gasket (seen to the right) Using spray foam Calculate true center of mass Currently center of mass can be counterweighted because payload weight is 3lbs max True center of mass will be known after material selection and counterweights are chosen Determination of Skin friction from CFD Determination of wall temperature from CFD

Flow Chart Diagram for Flight Test Ignition of Rocket Tripping of G-Switch Board Turns on Sensors Power on Code Execution Begins Is memory Full? Yes No Keep Executing Code Stop Code Splash Down Recovery of Rocket De-integrate Sensors Recovery of DATA Assessment of Test

Commands and Sensors Data Flow: Shear sensor -> Circuit board -> CPU -> Software -> Storage Sensor: –Operates in excess of 1000 degrees C. –Between 4 and 10 mm^2 in surface area. –Frequency response in the kHz range. Sampling: variable; factory default of 50Hz. Storage: 16MB. Sample time: ~2.7 minutes at 50Hz for 16-bit data. Software: Poll for incoming data -> optimize for storage -> store Maybe sample at very high Hz, store mean at low Hz.

Test Plans Preflight Testing: Sensor outputs between 0 and 5 V data. Our microprocessor/board has a software suite to test programs written for it. Feed it fake sensor data. Once those tests pass, we can attach the sensor to the board and run actual tests. Flight: Potential failure points: –Hardware failure. –Flight lasts longer than expected, run out of storage for samples.

Compliance and Shared Can Logistics –Compliance: Mass, Volume –Currently 3lb payload (not including can) Payload activation –Remove before flight pin –G switch No volt requirement???? –Can Logistics: Shared with VT VT supplies PC104+ VT has one other experiment (TBD) Both collaborate on rocket integration and design

UVA Hy-V 0.1 Team –Management Ryan Johnson-Program Manager Elizabeth Martin- Technical Advisor –Mechanical Engineering Archie Raval Shaun Masavage Jesse Quinlan –Aerospace Engineering Naeem Ahmed –Systems: Mitchell Foral Chris Sweeney

Schedule –Next few weeks Coordinate with NASA and Boulder on special requirements Order special components Material Selection Center of Mass Calculation Complete Systems Charts (Coding, Block Diagrams) Secure Funding –VSGC –ATK –Next Few Months Calculate expected shear Receive sensors Finish coding for PC104 Complete and finalize models –Run G Load analysis Determine max, min shear for sensor Determine Total temperature for sensor Run preliminary tests

Conclusion –We have A LOT to do!!!! We are not lazy, just have had bad luck Need to catch up, probably more than any other RockON Team Complete confidence that Hy-V Team can do this With the help of Advisors from UVA, VT, UC at Boulder, and NASA Wallops we can make this happen