The BRASS Project University of North Dakota Matthew Voigt Nathan Ambler Ron Fevig John Nordlie Tim Young Nirmal Patel (University of North Florida) Baike Xi November 3 rd, 2008 Balloon and Rocket Atmospheric Sampling and Sensing Conceptual Design Review

Mission Overview The Objective The altitude of the mesosphere is from 50 km to about 90 km. It is a poorly studied since it is too high for the aircraft or balloons, and too low for the orbiting spacecraft. To measure concentrations of H 2, O 2, CH 4, CO and possibly N 2 O in the mesosphere in nearly real-time using nanocrystalline oxide semiconductor sensor arrays and also simultaneously obtain information on the magnetic field strength.

Mission Overview To Prove Capability of in-situ atmospheric measurements on sounding rockets which has already been proven successful on high altitude balloons. To Discover The relative amounts of H, O, CH 4, CO, and N 2 O gasses in the mesosphere. Magnetic field strength over the change in altitude. New Insight Better data of H, O, CH 4, CO, and N 2 O gaseous composition in the mesosphere, an area often ‘ignored’ and not taken into account ie. atmospheric models. Also the use of nanocrystalline sensors arrays for the detection of gases in mesosphere.

Mission Overview The theory of the payload Nanocrystalline Oxide semiconductors such as Indium-tin oxide s olid state sensor arrays with different types of catalytic layers and stimulators for the detection of specific gases. Sensors will be calibrated in the lab. Also, a selectivity algorithm will be determined. Change in the electrical resistance with change in the concentration of gas gives the electrical signal for the sensors Resistance values will be recorded using flash memory. After data recovery and analysis, the concentration of different gases will be determined using the calibrated plots and selectivity algorithm. The magnetic field strength can be measured with a simple magnetometer The theory of the data The data can assist atmospheric models of our current atmosphere The magnetometer data will give field strength as a function of altitude The surface morphology of sensors before launch and after recovery will be examined using scanning electron microscope, while EDAX will be used to check the chemical composition of the surface of sensors.

Mission Overview Related Research Nanocrystalline solid state gas sensor arrays developed and fabricated by Dr. Nirmal Patel at University of North Florida (U.S. patent pending) had three balloon flights so far: 2007 in Florida (telemetry issues) 2008 in North Dakota (telemetry issues) 2008 HASP – successful flight and data obtained

Mission Overview Mission Requirements Sense apogee and evacuate the six vessels Seal all six vessels Collect an air sample every 20km during descent in the 130km to 30km range. Only 5 of the 6 vessels will be used. The 6 th is a baseline sealed at apogee Record resistance of all sensors and magnetometer data to flash memory via a microcontroller Atmospheric density changes exponentially, so the sampling frequency of collection may be changed Pre-flight testing of payload as per the guidelines including vibration and thermal tests.

Mission Overview Success Criteria Full evacuation of our six vessels Proper data fields acquired Data obtained from flash memory after recovery Benefits Local and national weather and atmospheric scientists will have additional data to pull from when reviewing improved models and experiments Atmosphere above 50km is not well known Natural pollution can enter the mesosphere (ie) CO 2

Payload Design Required Hardware 6 pressure vessels 6 solid state sensor boards 8 sensors on each board 4 gasses sampled twice, for redundancy 48 resistors Possibly few additional sensors as a back up and “test” resistors Ohm meter Microcontroller and circuits Flash memory Battery unit – Lithium Ion pack G-switch

Payload Design Required Hardware Continued Magnetometer Altimeter/timer board Atmospheric port manifold 6 valves leading to each vessel 6 solenoid valves Mounting plate Mounting hardware Remove Before Flight – for safety purposes Nylon Harnesses for “loose” wires Thermal protections/dust protecting material

Design Diagram

Functional Diagram The microcontroller will cycle the ohm meter between each sensor

RockSat Payload Canister User Guide Compliance Mass All of our allotted mass is required at this time A final mass is unknown at this time Volume All of our allotted volume is required, including a route to the atmospheric port Center of Gravity Our payload plate will have a CG located within a 1 inch of the center of radius of the canister Payload activation G-switch. Proven technique in past RockOn event The entire system will be powerless until the G-switch is activated A remove before flight “open” circuit will be used while the safety pin is plugged in.

Shared Can Logistics Plan Fellow Occupants of RockSat Canister Harding University Spectroscopy University of New Mexico Plan for collaboration on interfacing We plan to coordinate with the other Universities regarding location Harding University requires an optical port, while we require an atmospheric port. The University of New Mexico does not require a port. Structural interfacing Possibly consider RockOn structural design

Team Management

Schedule We are currently on time with the required schedule Upcoming Events: PDR requirements to be met ( / ) Further in-depth review of our payload layout, and integration of components Student team member slots all filled, and preliminary designs begun Canister integration with other teams investigated CDR requirements to be met( prior to holiday s ) Important constraints of payload reviewed and solved Canister integration planned

Budget and Funding Funding is currently being acquired from: North Dakota Space Grant Consortium Additional funding if required is under consideration

Conclusions Thermal considerations Upper atmosphere temperatures are very low Low power consumption heater will possibly be required for vessels Volumes of payload vessels Vessel’s volume significantly larger then tubing/manifold volumes Vessel volumes must be exact