Thermal Investigation for Accurate Temperature Measurement Team TCTJ Truc Le Cedric Toguem Jonathan Newman

Overview Mission Goal Objectives Science Background Technical Background Payload Design Electrical Software Mechanical Payload Development

Mission Goal The goal is to determine why previous LaACES payloads failed to correctly measure temperature in comparison to NOAA.

Objectives Measure the temperature inside and outside the boundary layer Measure the temperature with different color coated temperature sensors. Measure the temperature on the inside and on the outside surfaces of the payload. Have the payload returns intact.

Temperature change in the Atmosphere Troposphere (0 to 12km) : lowermost atmosphere where temperature decreases from 30 to -80 °C Stratosphere (12 to 48km): second lowermost part of the atmosphere where temperature increases from -80 to 0 °C

Boundary Layer Thin layer of fluid in contact with a solid body that flows more slowly than the rest of the fluid As the payload gains altitude in fluid air, the boundary layer around it will be affected by heat transfer processes

Heat Transfer Modes Heat can be transferred in three different ways: - Conduction - Convection - Radiation

Conduction Transfer of thermal energy between molecules due to temperature gradient The energy flows from a region of higher temperature to a region of lower temperature

Convection Movement of molecules within fluid A shallow layer of air in contact with a hotter surface warms by conduction, acquires buoyancy and then rises

Radiation Electromagnetic radiation emitted from the surface of an object in the form of heat due to the objects temperature If an object is warmer than its surrounding environment, it will emit more radiation in the form of heat into the surrounding environment than it will absorb in order to attain thermal equilibrium

Test 1: Radiation Test 1 Radiation test: Sun → Electromagnetic radiation → Space → Sensors The test will consist of different color shielding to reflect the electromagnetic radiation from the sun

Test 2: Radiation Test 2 Radiation Test: The payload circuitry will emit radiation to the sensor. Distance from the radiation source will determine the amount of heat dissipated

Test 3: Boundary Layer Test Sensors are placed at different distance from the exterior surface of the payload Determine how much effect the boundary layer has on the measured temperature

Thermal Boundary Layer

Payload Design

Electrical Design

Sensors

Sensor Interfacing

Flight Power Supply

Power Budget ComponentCurrent (mA) Duration (hrs.) Capacity (mA-h) BalloonSat51 (measured) 4275 RTDs (x7)1 each (estimated) 428 Total584303

Flight Software Pre-Flight and During Flight Sensor DataRead ADC BalloonSat Real Time Clock Write Read Memory

Flight Software Post-Flight: MemoryBalloonSatReadBasic Stamp Editor Excel

Flight Software Onboard Flight Program: Loop Pause Read Write EndIf/Then

Flight Software Post Flight Program: AnalyzeReadTransfer to Excel

Exterior Mechanical Design

Interior Mechanical Design

Weight Budget ComponentWeight (g) BalloonSat66 (measured) Styrofoam Structure150 (estimated) BalloonSat Styrofoam Attachments 25 (estimated) Wiring7.5 (estimated) Booms (if balsa)3 (estimated) Booms (if plastic)10 (estimated) Boom attachments25 (estimated) Sensors10(estimated) Total /- 25%

Payload Development Plan Mechanical ◦ Boom prototyping ◦ Attachment prototyping ◦ Impact test to find best design to store components ◦ Maintain payload within regulation

Payload Development Plan Electrical ◦ Determine best temperature sensor to use ◦ Determine best batteries to use and its configuration ◦ Design the circuitry of the system ◦ Determine how well the components will function in flight climate ◦ Determine methods of calibration of the sensors

Payload Development Plan Software ◦ Determine best way to consume less power ◦ Determine if extra memory will be needed and how to access it ◦ Determine the timing sequence ◦ Determine methods of calibration

Reference 1. Clavius: Environment - heat transfer. November 24, Anne E. Egger "Earth's Atmosphere: Composition and Structure," Visionlearning Vol. EAS Sad Dr Rodrigue – Introduction to physical Geaography. re.html re.html 4. BASIC Stamp 2p 24-Pin Module. dules/tabid/134/ProductID/7/List/1/Default.aspx?SortField=UnitC ost,ProductName. November 25, dules/tabid/134/ProductID/7/List/1/Default.aspx?SortField=UnitC ost,ProductName

Questions?