Thermion: Verification of a thermionic heat pipe in microgravity

270 Pages·8.3 MB·English

by  NON

NASW-4435
THERMION: VERIFICATION OF A THERMIONIC
HEAT PIPE IN MICROGRAVITY
UTAH STATE UNIVERSITY
1990- 1991
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FORWARD
This final report describes the verification of a thermionic heat pipe in microgravity.
This project consists of two design scenarios: THERMION-I andTHERMION-II. The
design was done entirely by a team of Utah State University (USU) students. The
project has been completed under the sponsorship of NASA through the Universities
Space Research Association (USRA) and in cooperation with the Idaho National
Engineering Laboratory (INEL).
We at Utah State University are very pleased with the results of this design effort.
We are proud of the product, and we are excited about the achievement of all our
learning objectives. The systems design process is one that cannot be taught, it must
be experienced. The opportunity to use our maturing engineering and scientific skills
in producing the THERMION final design has been both challenging and rewarding.
We are proud of the skills we have developed in identifying system requirements,
spreading them into specifications, communicating with each other in all kinds of
technical environments, conducting parametric and trade-off studies, learning to
compose for the good of the system, and selecting actual hardware to be used.
The critical design review (CDR), conducted in May of this year at USU, was
presented to INEL, Phillips Laboratory, JPL, and Space Dynamics Laboratory/USU
personnel as well as other distinguished members of the engineering community. A
revision of the paper will be presented at the AIAA/USU Conference on Small
Satellites in August of this year. INEL and Phillips Laboratory, in collaboration with
the Space Dynamics Laboratory/USU, are considering further development and testing
of the THERMION project.
We would like to express our appreciation and thanks to the following people who
have helped us with this design project:
Frank J. Redd, class professor, MAE Department Head, USU
Michael Jacox, INEL, SEHPTR Project Manager
Kevin Horner-Richardson, Thermacore, Inc.
James Burke, Jet Propulsion Laboratory
John Garvey, McDonnell Douglas
J. Clair Batty, professor, MAE Department, USU
Ralph Haycock, professor, MAE Department, USU
Ed Vendell, professor, MAE Department, USU
Kay D. Baker, professor, EE Department, USU
Robert Gunderson, professor, EE Department, USU
John Kemp, professor, EE Department, USU
Pete Brunson, artist, Space Dynamics Lab/USU
David Widauf, professor, ITE Department, USU
R. Gilbert Moore, Physics Department, USU
Shelly Wegener, technical writer, Space Dynamics Lab/USU
Frank J. Redd, PhD George E. Powell
Professor, MAE Teaching Assistant

THERMION: VERIFICATiON OF A THERMIONIC
HEAT PIPE IN MICROGRA WTY
ABS TRA C T
The Idaho National Engineering Laboratory (INEL) is conducting intensive research
in the design and development of a small, excore heat-pipe-thermionic space
nuclear reactor power system (SEHPTR). Progress in this research effort has
identified the need for an in-space flight demonstration of a solar-powered,
thermionic heat-pipe element. The proposed demonstration will examine the
performance of such a device and verify its operation in microgravity.
The Utah State University space system design project for 1990-1991 focuses on
the design of a microsatellite-based technology demonstration experiment to
measure the effects of microgravity on the performance of an integrated
thermionic-heat-pipe device in low-earth orbit. The specific objectives are to verify
the operation of the liquid-metal heat pipe and the cesium reservoir in the space
environment. The scope of the project includes the design of the flight test
vehicle, the solar collection subsystem, the satellite attitude control subsystem,
test instrumentation, data collection/processing and the telemetry subsystem.
Interfaces with various launch systems are examined with emphasis on flight as
secondary payload on the McDonnell Douglas Delta II.
This report describes two design configurations, THERMION-I and THERMION-II,
which meet the requirements specified above. THERMION-I is designed for a long-
lifetime (greater than one year) investigation of the operations of the thermionic
heat pipe element in low earth orbit. Heat input to the element is furnished by a
large mirror which collects solar energy and focuses it into a cavity containing the
heat pipe device. THERMION-II is a much simpler design which is utilized for
short-term (approximately one day) operation. This experiment remains attached
to the Delta II second stage and utilizes energy from 500 Ib of alkaline batteries to
supply heat energy to the heat pipe device. The cost for fabrication, integration
and flight are estimated at almost $3 million.

CLA SS PAR TICIPA N TS
THERMION I
GEORGE POWELL System Engineering
WALTER HOLEMANS System Engineering
SCOTT BLADEN Payload
EDWIN ROWSELL Payload
RUSSELL FERGUSON Payload
RICHARD WEATHERSTON Payload
GLEN PETERSON Attitude Determination & Control
BART EWER Attitude Determination & Control
PAUL WHEELWRIGHT Attitude Determination & Control
RICK BJORN Structure
MIKE OLSEN Structure
GEORGE POWELL Data Management & Storage
RUSSELL MIKESELL Communications
WALTER HOLEMANS Power System
SHAUN ANDERSON Launch Vehicle Interface & Deployment
MARK RAWLINGS Launch Vehicle Interface & Deployment
GREG FERNEY Thermal Management
JEFF HIRASUNA Thermal Management
RUSSELL MIKESELL Test & Evaluation
THERMION II
WALTER HOLEMANS System Engineering
GEORGE POWELL System Engineering
WALTER HOLEMANS Power System
JONATHON BLOTTER Launch Vehicle Interface & Payload
VAL MOSER Launch Vehicle Interface & Payload
GEORGE POWELL Data Management & Communications

TABLE OF CONTENTS
1.0 INTRODUCTION
1.1 DESIGN PROJECT
1.1.1 THERMION-I
1.1.2 THERMION-II
1.2 DESIGN CONSTRAINTS
1.3 DESIGN EVOLUTION OF THERMION-I
1.3.1 Heat Pipe Testing System
1.3.2 Solar Collection System
1.3.3 Attitude Control and Determination System
1.3.4 Satellite Structure and Configuration System
1.3.5 Data Management System
1.3.6 Communications System
1.3.7 Power System
1.3.8 Launch Vehicle Interface and Deployment System
1.3.9 Thermal Management System
1.3.1 0 Test and Evaluation System
1.3.1 1 Conclusions
2.0 PA YLOAD
2.1 THERMIONIC HEAT PIPE DEVICE
2.2 INSULATING CAVITY
2.2.1 Design Evolution
2.2.2 Insulating Cavity
2.2.3 Isulation
2.3 SOLAR COLLECTION
2.3.1 Solar Design Constraints
2.3.1.1 FresnelLens
2.3.1.2 Inflatable Collector
2.3.1.3 Reflecting Mirror
2.3.2 Solar Concentrating Mirror
2.3.2.1 Mirror's Configuration and Operation
2.3.2.2 Mirror's Reflective Surface
2.3.2.3 Structure and Strength of the Mirror
2.3.3 Secondary Concentrator
2.4 POWER MEASURING DEVICE
2.4.1 Conceptual Operation
2.4.2 Governing Equations
2.5 TEMPERATURE MEASUREMENT
2.5.1 Sensor Configuration
2.6 CONCLUSIONS
2.6.1 Conceptual Design
2.6.2 Options and Concerns
3.0 A TTITUDE DETERMINA T/ON AND CONTROL
3.1 DESIGN REQUIREMENTS
3.2 DESIGN EVOLUTION
3.3 ATTITUDE DETERMINATION SENSORS
3.3.1 Sun Sensors
3.3.2 Horizon Crossing Sensor
3.4 ATTITUDE CONTROL ACTUATORS
3.4.1 Torque Rods
3.4.2 Momentum Wheel
3.5 ENVIRONMENTAL TORQUES
3.6 EQUATIONS OF MOTION AND CONTROL LOGIC
3.6.1 Control Simulation
3.7 FUTURE DESIGN WORK
4.0 STRUC TURES
4.1 SYSTEM REQUIREMENTS
4.2 STRUCTURE
4.2.1 Design Phases
4.2.2 Final Design
4.3 DEPLOYMENT
4.4 MATERIALS
4.4.1 Subsystem Housing
4.4.2 Attachment Bracket and Hinge
4.4.3 Payload Arm
4.4.4 Shielding and Mounts
4.5 SUBSYSTEM LAYOUT
4.6 MASS PROPERTIES
4.7 CONCLUSIONS
5.O DATA MANAGEMENT
5.1 DATA MANAGEMENT REQUIREMENTS
5.2 SYSTEM COMPONENTS
5.2.1 CPU
5.2.2 Expanded Memory
5.2.3 Data Acquisition
5.2.3.1 Cavity Temperature
5.2.3.2 Data Rates
5.2.4 Housekeeping
5.2.5 Storage Container
5.3 RADIATION DAMAGE PREVENTION
5.4 CONCLUSIONS
6.0 COMMUNICATIONS
6.1 REQUIREMENTS
6.2 COMMUNICATION SYSTEM
6.2.1 THERMION-I Satellite Antenna
6.2.2 Ground Station Antenna
6.2.3 Spacecraft Transmitter and Receiver