PACER Summer Program
Critical Design Review Document
For the
High-Altitude Thermodynamics Profile and Clarity Experiment
By
Team PACER-GSU
Prepared by:
Johnte Bass Date
Herman Neal Date
Matthew Ware Date
Submitted:
Reviewed:
Revised:
Approved:
Institution Signoff (replace with name) Date
Institution Signoff (replace with name) Date
LA SPACE Signoff Date
Change Information Page
Title: CDR Document for Pacer Experiment
Date: 07/13/2007
List of Affected Pages
Page Number
/ Issue / DateTBD
Number
/ Section / Description / DateCreated / Date Resolved
Status of TBDs
TABLE OF CONTENTS
Cover i
Change Information Page ii
Status of TBDs iii
Table of Contents iv
List of Figures v
List of Tables vi
1.0 Document Purpose 1
1.1 Document Scope 1
1.2 Change Control and Update Procedures 1
2.0 Reference Documents 2
3.0 Goals, Objectives, Requirements 3
3.1 Mission Goal 3
3.2 Objectives 3
3.3 Science Background and Requirements 3
3.4 Technical Background and Requirements 3
4.0 Payload Design 4
4.1 Principle of Operation 4
4.2 System Design 4
4.3 Electrical Design 9
4.3 Software Design 12
4.4 Thermal Design 13
4.5 Mechanical Design 14
5.0 Payload Development Plan 16
6.0 Payload Construction Plan 16
6.1 Hardware Fabrication and Testing 16
6.2 Integration Plan 16
6.3 Software Implementation and Verification 16
6.4 Flight Certification Testing 17
7.0 Mission Operations 17
7.1 Pre-Launch Requirements and Operations 17
7.2 Flight Requirements and Operations 17
7.3 Data Acquisition and Analysis Plan 17
8.0 Project Management 19
8.1 Organization and Responsibilities 20
8.2 Configuration Management Plan 20
8.3 Interface Control 20
9.0 Master Schedule 20
9.1 Work Breakdown Structure 20
9.2 Staffing Plan 22
9.3 Timeline and milestones……………………………………………………………….23
10.0 Master Budget 22
10.1 Expenditure Plan 22
10.2 Material Acquisition Plan 22
11.0 Risk Management and Contingency 23
12.0 Glossary 24
LIST OF FIGURES
1. Figure on expected science results 3
2. Block diagram of payload systems 5,6,7
3. Schematic of sensor electronics 10
4. Schematic of power system 11
5. Flight software flow chart 13
6. External structure……………………………………………………………………………14
8. Internal structure…………………………………………………………………………….15
7. Ground software flow chart 18
8. Data Analysis………………………………………………………………………………..19
9. Work breakdown structure…………………………………………………………………20,21
10. Project organization chart 22
LIST OF TABLES
1. Goals versus measurement traceability matrix 8
2. Power budget table 12
3. Data format and storage 12
4. Weight budget table 15
5. Flight certification check list 17
6. Organization and Responsibilities 20
7. Project budget 22
8. Material acquisition plan……………………………………………………………………22
9. Risk management table……………………………………………………………………...23
10. Contingency Table…………………………………………………………………………23
iv
Team PACER-GSU CDR v1.2
1.0 Document Purpose
This document describes the Critical Design for the Atmospheric Thermodynamics Profile and Clarity experiment by PACER-GSU for the PACER Summer Program. It fulfills part of the PACER Summer Program Project requirements for the Critical Design Review (CDR) to be held July 13, 2007.
1.1 Document Scope
This CDR document specifies the scientific purpose and requirements for the High-Altitude Thermodynamics Profile and Clarity experiment and provides a guideline for the development, operation and cost of this payload under the PACER Project. The document includes details of the payload design, fabrication, integration, testing, flight operation, and data analysis. In addition, project management, timelines, work breakdown, expenditures and risk management is discussed. Finally, the designs and plans presented here are preliminary and will be finalized at the time of the Critical Design Review (CDR).
1.2 Change Control and Update Procedures
Changes to this CDR document shall only be made after approval by designated representatives from Team PACER-GSU and the PACER Institution Representative. Document change requests should be sent to Team members, the PACER Institution Representative and the PACER Project.
2.0 Reference Documents
Trickle-Charge Time Keeping Chip (DS 1302) reference model
Pressure Sensor (model 1210) reference model
Basic Stamp Command (12CIN) reference model
EEPROM (24L64) reference model
Voltage Output Temperature Sensor (AD 22100) reference model
B. Gerts and E. Linacre, “The height of the troposphere,” (http://www-das.uwyo.edu/~geerts/cwx/notes/chap01/tropo.html), November 1997.
University of Wyoming College of Engineering Department of Atmospheric Science Upper Air Soundings (http://weather.uwyo.edu/upperair/soundings.html)
3.0 Goals, Objectives, Requirements
3.1 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.
3.2 Objectives
3.2.1 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. Develop a reflectance profile of the atmosphere.
7. Compare models of the atmosphere to measurements.
8. Present findings.
3.2.2 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 an onboard camera for the duration of the flight.
6. Store thermodynamic and photographic data onboard the payload.
7. Correlate payload data with mission telemetry data to determine the altitude of each measurement.
3.3 Science Background and Requirements
3.3.1 Science Background
This payload will ascend through the troposphere, the tropopause, and into the stratosphere to the upper boundary of the ozone maximum.
The word troposphere comes from tropein, meaning to turn or change. All of the earth's weather occurs in the troposphere. It extends from the earth's surface to the tropopause. Within the troposphere, the temperature generally decreases with increasing height, dropping from an average of 15 ˚C (59 ˚F) near the surface to an average of -57 ˚C (-71 ˚F) at the tropopause.
The tropopause is the transition layer between the troposphere and the stratosphere. It begins where the temperature no longer varies with height. On average, the lower boundary of the tropopause has an altitude of 12 km (7 mi); the upper boundary, an altitude of approximately 21 km (13 mi).
The height of the tropopause depends on location, particularly the latitude. It also depends on the season. Over Australia, the height of the tropopause varies from 12-16 km at midyear to 16 km at year-end. At latitudes above 60˚, the tropopause is less than 9-10 km above sea level. The lowest tropopause is less than 8 km above Antarctica and above Siberia and above Siberia and northern Canada in winter. The highest average tropopause is over the oceanic warm pool of the western equatorial Pacific, about 17.5 km high, and over Southeast Asia. During summer monsoon, the tropopause occasionally peaks above 18 km.
3.3.2 Science Requirements
1. Measure temperature to within 1 ˚C.
2. Measure pressure to within 5 mbar (0.5% at sea level).
3. Calculate density to within 5% error.
4. Make measurements every 15 seconds.
5. Determine altitude to within 100 meters.
6. Take photographs up to an altitude of 100,000 feet.
3.4 Technical Background and Requirements
3.4.1 Technical Background
The experiment will be performed by an instrument payload which will be secured between two strings beneath a latex helium sounding balloon. The payload will rise at an approximate rate of 850 ft. per minute. The experiment will operate for the duration of the flight which will be approximately three hours. The payload will be self-contained with respect to electric power, computer control, and data storage. It will rely on a GPS beacon located in another payload on the flight string for latitude, longitude, and altitude.
The payload will take measurements of ambient temperature and pressure. An onboard camera will photograph the environment. All measurements taken with onboard instrumentation will be time stamped. The time stamp will allow payload-based measurements to be correlated with GPS data in post-flight data analysis.
Temperature will be measured using an Analog Devices AD22100 monolithic temperature sensor with on-chip signal processing. The temperature sensor is powered by 8 to 12 V dc. Pressure will be measured by an ICSensors Model 1210 temperature compensated piezoresistive silicon pressure sensor. The pressure sensor is powered by 8 to 12 V dc. These measurements will initially be analog data but will then be sent to the ADC on the BalloonSat and will then be converted to digital data. This data will then be sent to the EEPROM for storage. All of the measurements will be made under the control of a BASIC Stamp microprocessor and archived in EEPROM nonvolatile memory. These devices are integrated with the BallonSat and share its power. Power for the BalloonSat will be provided by a 8 to 12 V lithium battery. Photographs will be taken with a VistaQuest VQ1005 digital camera triggered by the BASIC Stamp and stored on a 512 MB Secure Digital flash card. The camera will be powered by a separate 1.5 V lithium battery. All measurements will be time-stamped using a real time clock onboard the BalloonSat.
3.4.2 Technical Requirements
1. Payload must remain intact from launch to recovery.
2. 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.
3. Temperature sensor able to measure over the range -80 ˚C ≤ T ≤ 40 ˚C.
4. Pressure sensor able to measure over the range 5 mbar ≤ P ≤ 1000 mbar.
5. Camera able to operate over the temperature range -80 ˚C ≤ T ≤ 40 ˚C and pressure range 5 mbar ≤ P ≤ 1000 mbar.
6. Record time to 15 second accuracy.
7. Data archive system with the capacity to store measurements by the sensors and real time clock for the duration of the flight.
8. Photograph storage medium with the capacity to store about 2000 high-resolution pictures.
9. Ground system which can download, analyze, and present payload measurements.
4.0 Payload Design
The payload will consist of a power supply connected to the BalloonSat and external sensors. The payload will have a data converter, a data storage unit, a sensor to measure the temperature, a sensor to measure the pressure, and a camera to take photographs of the atmosphere.
4.1 Principle of Operation
Temperature will be measured using an Analog Devices AD22100 monolithic temperature sensor with on-chip signal conditioning.
Pressure will be measured using an ICSensors Model 1210 temperature compensated piezoresistive silicon pressure sensor.
Photographs will be taken using a VistaQuest VQ1005 digital camera. They will be stored on a 512 MB Secure Digital flash memory card attached to the camera.
The payload will be controlled by a BASIC Stamp embedded microprocessor. The ADC will convert all payload-collected thermodynamic and temporal data to digital form and archive it in EEPROM non-volatile memory.
4.1 System Design
4.1.1 Functional Components
Mechanical. The container will hold all instruments for the payload. It must secure each instrument and protect it against the shocks of the ascent and landing.
Thermal. It will also provide the thermal insulation for the instruments which will protect them from the cold temperatures of the upper troposphere, tropopause, and lower stratosphere. The thermal system is the insulating sheathing used to construct the box and the heat generated by the electrical components within the payload during operation.
Power. Batteries must provide sufficient power for the duration of the flight to power the controller, all of the instruments, and the data archive.
Sensors. A temperature sensor will measure the ambient temperature. A pressure sensor will measure the ambient pressure. A digital camera will photograph the environment outside the payload.
Processor. A BASIC Stamp processor is integrated with the BalloonSat.
Data Archive. An EEPROM onboard the BalloonSat archives data collected by the temperature and pressure sensors and real time clock. A 512 MB Secure Digital card is inserted into the camera’s integrated SD card slot to store the photographs taken by the camera.
4.1.2 Component Interfacing
A 12 volt battery will be electrically wired to the BalloonSat, the sensors and the EEPROM and supply voltage throughout it. Control signals will be sent to the sensors from the BalloonSat and in return the BalloonSat will receive wired analog data from the sensors. The EEPROM is receiving and sending digital data to and from the BalloonSat. The ground support system is interfaced to the EEPROM and the BalloonSat via digital data. The mechanical support system is interfaced mechanically to both the BalloonSat circuit board and the thermal system. The thermal system is interfaced thermally to both the BalloonSat circuit board and the mechanical system.
4.1.3 Traceability
Requirement / Subsystem Implemented / Method of Verification / Successful Test Verification /Measure temperature to within 1 ˚C. / Sensor Subsystem / Calibrate temperature sensor down to dry ice temperature.
Measure pressure to within 5 mbar. / Sensor Subsystem / Calibrate pressure sensor between atmospheric pressure and a vacuum.
Calculate density to within 5% error. / Sensor Subsystem
Ground System / Test Excel spreadsheet using a known set of temperature and pressure values.
Make measurements every 15 seconds. / Sensor Subsystem / Simulate a flight in the laboratory.
Determine altitude to within 100 meters. / Sensor Subsystem
Ground System / Correlate time stamps for simulated flights with GPS data from previous flights.
Take photographs up to an altitude of 100,000 feet. / Sensor Subsystem / Simulate a flight in the laboratory for the expected duration of the flight.
Payload must remain intact from launch to recovery. / Mechanical Subsystem / Perform vacuum tests, cold tests, and drop the payload from a height of 8 feet onto a turf surface.
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 Subsystem
Mechanical Subsystem
Thermal Subsystem / Simulate a flight in the laboratory down to dry ice temperature.
Temperature sensor able to measure over the range -80 ˚C ≤ T ≤ 40 ˚C. / Sensor Subsystem / Calibrate temperature sensor down to dry ice temperature.
Pressure sensor able to measure over the range 5 mbar ≤ P ≤ 1000 mbar. / Sensor Subsystem / Calibrate pressure sensor between atmospheric pressure and a vacuum.
Camera able to operate over the temperature range -80 ˚C ≤ T ≤ 40 ˚C and pressure range 5 mbar ≤ P ≤ 1000 mbar. / Sensors Subsystem
Mechanical Subsystem / Simulate a flight in the laboratory for the expected duration of the flight.
Synchronize data acquisition to time stamp within 7 seconds. / Sensors Subsystem / Correlate time stamps for simulated flights with GPS data from previous flights.
Data archive system with the capacity to store measurements by the sensors and real time clock for the duration of the flight. / Data Archive / Simulate a flight in the laboratory for the expected duration of the flight.
Photograph storage medium with the capacity to store about 2000 high-resolution pictures. / Data Archive / Simulate a flight in the laboratory for the expected duration of the flight.
Ground system which can download, analyze, and present payload measurements. / Ground System / Test post-flight software using data gathered during simulated flights.
4.2 Electrical Design