1. PACER Summer Program High-Altitude Thermodynamics Profile and Clarity Experiment (HATPaC) Johnte Bass, Herman Neal, Matthew Ware

2. Mission Goal Investigate the temperature, pressure, density and clarity as a function of altitude up to about 100,000 feet in order to study layering in Earth’s lower atmosphere. Investigate the temperature, pressure, density and clarity as a function of altitude up to about 100,000 feet in order to study layering in Earth’s lower atmosphere.

3. Science Background The payload will ascend through the troposphere, the tropopause, and into the stratosphere to the upper boundary of the ozone maximum. This figure represents a typical temperature profile of the layers of the atmosphere. However, the specific profile depends on location, particularly the latitude. There is also a seasonal variation with the tropopause at higher altitudes in summer at latitudes smaller than 60°. The HATPaC experiment will measure the profile over East Central Texas (35° latitude) in midsummer.

4. Science Background (continued) The tropopause is characterized by a region several kilometers thick where the temperature is relatively constant. High altitude sounding measurements indicates that temperature over 2 km altitude range varies 3 °C or less. This figure shows the pressure and density profiles as determined by the NRLMSISE Standard Atmosphere Model. The atmosphere may be considered as an ideal gas. The ideal gas law may be used to calculate the density from measurements of pressure and temperature:  = MP/RT.

5. Science Objectives 1.Identify the zones of the Earth’s lower atmosphere. 2.Determine the altitude of the tropopause. 3.Develop a temperature profile of the atmosphere. 4.Develop a pressure profile of the atmosphere. 5.Develop a density profile of the atmosphere. 6.Qualitatively evaluate atmospheric clarity as altitude varies. 7.Compare accepted models of the atmosphere to measurements. 8.Present findings

6. Science Requirements Make measurements every 15 seconds. Make measurements every 15 seconds. Calculate density within 5% uncertainty which includes: Calculate density within 5% uncertainty which includes:   Measure temperature to within 1 °C (0.5% at the tropopause).   Measure pressure to which 1 mbar (5% at the tropopause). Determine the altitude to within 100 meters. Take photographs during ascent and descent every 15 seconds up to an altitude of 100,000 feet.

7. Technical Objectives 1.Build and fly a payload and retrieve the data. 2.Measure temperature over the range -80 ˚C ≤ T ≤ 40 ˚C. 3.Measure pressure over the range 5 mbar ≤ P ≤ 1000 mbar. 4.Calculate the atmospheric density using the ideal gas law. 5.Take photographs of the external environment using two onboard cameras for the duration of the flight. The two cameras will provide an overlapping field of view from 10˚ above the horizon to 60˚ below the horizon. 6.Store thermodynamic data in memory contained within the payload control computer and photographic images in flash memory within the cameras. 7.Correlate payload data with mission telemetry data to determine the altitude of each measurement.

8. Technical Requirements Payload must remain intact from launch to recovery. Payload must remain intact from launch to recovery. Power system must operate over the temperature range -80 °C ≤ T ≤ 40 °C with the capacity to power the BalloonSat, sensors, and data archive for the duration of the flight. Power system must operate over the temperature range -80 °C ≤ T ≤ 40 °C with the capacity to power the BalloonSat, sensors, and data archive for the duration of the flight. Temperature sensor able to measure over the range -80 °C ≤ T ≤ 40 °C. Temperature sensor able to measure over the range -80 °C ≤ T ≤ 40 °C. Pressure sensor able to measure over the range 5 mbar ≤ P ≤ 1000 mbar. Pressure sensor able to measure over the range 5 mbar ≤ P ≤ 1000 mbar. Camera able to operate over the temperature range -80 °C ≤ T ≤ 40 °C and pressure range 5 mbar ≤ P ≤ 1000 mbar. Camera able to operate over the temperature range -80 °C ≤ T ≤ 40 °C and pressure range 5 mbar ≤ P ≤ 1000 mbar. Record time to 15 second accuracy. Record time to 15 second accuracy. Data archive system with the capacity to store measurements by the sensors and real time clock for the duration of the flight (approximately 750 data records) Data archive system with the capacity to store measurements by the sensors and real time clock for the duration of the flight (approximately 750 data records) Photograph storage media with the capacity to store about 1500 1.3 megapixel (1600  1200 pixels) images. Photograph storage media with the capacity to store about 1500 1.3 megapixel (1600  1200 pixels) images. Ground system which can download, analyze, and graphically display payload measurements. Ground system which can download, analyze, and graphically display payload measurements.

9. Sensor Subsystem Schematic

10. Power Subsystem Schematic

11. Data Storage Format NameBytes Sequence No.2 Hour1 Minute1 Seconds1 Temperature Outside 1 1 Temperature Outside 2 1 Temperature Inside1 Pressure1

12. Flight Software Flow Chart

13. Payload Construction The Pacer payload is constructed using a material called Foamular. The Pacer payload is constructed using a material called Foamular. This type of material can withstand extreme temperatures, pressure and shock from the landing of the payload. This type of material can withstand extreme temperatures, pressure and shock from the landing of the payload. The material that will reinforce the payload is silver mylar which can withstand cold temperatures and also work as a good insulator. The material that will reinforce the payload is silver mylar which can withstand cold temperatures and also work as a good insulator. The plywood that the camera are on is stuck together with the cameras using Gorilla Glue. The plywood that the camera are on is stuck together with the cameras using Gorilla Glue.

14. Mechanical Design Closed Capsule (Right Side View) Closed Capsule (Right Side View) Closed Capsule (Left Side View) Closed Capsule (Left Side View)

15. Mechanical Design (continued) Lid (Top View) Lid (Top View) Lid (Side View) Lid (Side View)

16. Mechanical Design (continued) Capsule Interior w/o BalloonSat Capsule Interior w/o BalloonSat Capsule Interior w/BalloonSat Capsule Interior w/BalloonSat

17. Thermal Test

18. Shock Test

19. Power BudgetComponent Voltage (V) Current (mA) Power (mW) Duty Cycle (%) BalloonSatSubsystem8–1260720100 Data Archive On BalloonSat 100 Temperature Sensors 8–12896100 Pressure Sensor 8–12560100 Relays5241203 Cameras-idling (each camera) 220040085 Cameras-during exposure (each camera) 232064015

20. Weight BudgetComponents Weight (grams) Case172 Two Exterior Temperature Sensors 11 Pressure Sensor Included on Daughtercard Batteries for Camera 87 Batteries for BalloonSat 85 Two Cameras 73 Power Connectors 8 BalloonSat and Daughtercard 149 Total585

21. Pacer Flight Pressure vs. Altitude

22. Pressure Sounding Profile

23. Pressure Profile

24. Temperature Sounding Data

25. Inside Temperature Profile

26. Outside Temperature Profile

27. Temperature Sensor Comparison

28. Density Profile

30. At Peak

31. Retrieval

32. PACER HATPaC Flight Badge Combination of the US Army 93rd Infantry Division patch and GSU logo. The 93rd was to fight in World War I, but was sent to France to help the French Army. The object covering the GSU logo is the French steel helmet. The 93rd’s Division badge has the same colors as GSU. Herman Neal is an US Army veteran. Dr. Ware’s father served in the Infantry in France during World War I.

33. Acknowledgements PACER PACER LaSPACE, the Louisiana Space Grant Consortium LaSPACE, the Louisiana Space Grant Consortium National Science Foundation National Science Foundation NASA Columbia Scientific Balloon Facility NASA Columbia Scientific Balloon Facility Louisiana State University-Baton Rouge Louisiana State University-Baton Rouge