Re-entry and Planetary Entry Physics and Technology: I / Dynamics, Physics, Radiation, Heat Transfer and Ablation

491 Pages·1968·11.446 MB·English

by  W. H. T. Loh (auth.), W. H. T. Loh (eds.)

Volume 2
APPLIED PHYSICS AND ENGINEERING
An International Series
Re-entry and Planetary Entry
Physics and Technology
Re-entry and Planetary Entry
Physics and Technology
I / Dynamics, Physics, Radiation,
Heat Transfer and Ablation
Edited and authored by W. H. T. Loh
NORTH AMERICAN ROCKWELL CORPORATION
DOWNEY, CALIFORNIA
ill
Springer-Verlag New York Tnc.· 1968
All rights reserved.
No part of this book may be translated or reproduced in any form without
written permission from Springer-Verlag.
lSBN-13: 978-3-642-48929-7 e-lSBN-13: 978-3-642-48927-3
DOl: 10.1007/978-3-642-48927-3
© 1968 by Springer-Verlag New York Inc.
Softcover reprint of the hardcover 1s t edition 1968
Library of Congress Card Number 68-18103
Title No. 3892
To
PRESIDENT JOHN F. KENNEDY
for his decision to land men on the moon
in this decade
and
NASA ADMINISTRATOR JAMES E. WEBB
for his achievements
to carry out our national goal in space
Preface
During the last decade, a rapid growth of knowledge in the field of
re-entry and planetary entry has resulted in many significant advances
useful to the student, engineer and scientist. The purpose of offering this
course is to make available to them these recent significant advances in
physics and technology.
Accordingly, this course is organized into five parts: Part 1, Entry
Dynamics, Thermodynamics, Physics and Radiation; Part 2, Entry Abla
tion and Heat Transfer; Part 3, Entry Experimentation; Part 4, Entry
Concepts and Technology; and Part 5, Advanced Entry Programs. It is
written in such a way so that it may easily be adopted by other universities
as a textbook for a two semesters senior or graduate course on the sub
ject. In addition to the undersigned who served as the course instructor
and wrote Chapters, 1, 2, 3 and 4, guest lecturers included: Prof.
FRANKLIN K. MOORE who wrote Chapter 5 "Entry Radiative Transfer,"
Prof. SHIH-I PAl who wrote Chapter 6 "Entry Radiation-Magnetogasdy
namics," Dr. CARL GAZLEY, Jr. who wrote Chapter 7 "Entry Deaccelera
tion and Mass Change of an Ablating Body," Dr. SINCLAIRE M. SCALA
who wrote Chapter 8 "Entry Heat Transfer and Material Response," Mr.
DAVID G. STONE who wrote Chapter 9 "Entry Flight Research and Experi
mentation," Dr. JOSEPH G. LOGAN who wrote Chapter 10 "Lifting Re-entry
Concepts," Dr. JOHN F. MCCARTHY, Jr. who wrote Chapter 11 "Earth
Entry from Lunar and Planetary Missions," Dr. KRAFFT A. EHRICKE who
wrote Chapter 12 "Braking Entry of Mars and Venus," Dr. ROBERT W.
BUSSARD who wrote Chapter 13 on "Entry Propulsion and Power Tech
nology," Dr. ROBERT C. DUNCAN who wrote Chapter 14 "Entry Guidance
and Control Technology," Dr. WILLIAM T. THOMSON who wrote Chapter
15 "Dynamics Problem of Planetary Approach," and Dr. JOSEPH F. SHEA
who wrote Chapter 16 "Entry Programs Management." The material in
Setion 8 of Chapter 3 on "High Temperature Properties of Gases" was
written by Dr. KENNETH G. SEWELL of LTV Research Center and the
material in Section 2 of Chapter 4 on "Orbital Maneuver" was written by
Dr. GEZA S. GEDEON of TRW Systems.
Los Angeles, California
University of California W. H. T. LOH
Contents
Preface
Introduction
Chapter 1. Summary Discussion on Re-entry and
Planetary Entry: Physics and Technology (W. H. T. LOH) 1
Part One. Entry Dynamics, Thermodynamics,
Physics and Radiation
Chapter 2. Entry Mechanics (W. H. T. LOH) 19
Chapter 3. Entry Thermodynamics (W. H. T. LOH) 179
Chapter 4. Orbital and Celestial Mechanics (W. H. T. LoH). 275
Chapter 5. Entry Radiative Transfer (F. K. MOORE) 343
Chapter 6. Entry Radiation-Magnetogasdynamics (S. I. PAl). 372
Part Two. Entry Ablation and Heat Transfer
Chapter 7. Entry Deceleration and Mass Change
of an Ablating Body (C. GAZLEY) ........... . 415
Chapter 8. Entry Heat Transfer and Material
Response (S. M. SCALA) .... . .......... . 436
vii
List of Contributors
CARL GAZLEY, JR. S. I. PAl
Aero-astronautics Dept. Institute for Fluid Dynamics
The Rand Corporation and Applied Mathematics
Santa Monica, California University of Maryland
College Park, Maryland
FRANKLIN K. MOORE
Professor and Chairman SINCLAIRE M. SCALA
Mechanical Engineering Manager, Theoretical Fluid Physics
Cornell University G. E. Space Science Lab
Ithaca, New York Valley Forge, Pennsylvania
Contents of Re-Entry and Planetary Entry
II / ADVANCED CONCEPTS, EXPERIMENTS, GUIDANCE
CONTROL AND TECHNOLOGY
Part Three. Entry Experimentation
Chapter 9. Entry Flight Research and Experimentation
(D. G. STONE) .............................................................................. 3
Part Four. Entry Concepts and Technology
Chapter 10. Lifting Entry Concepts (J. G. LOGAN) .................. 29
Chapter 11. Entry from Lunar and Planetary
Missions (J. F. MCCARTHY) ........................................................ 77
Chapter 12. Atmospheric Braking Entry and
Associated Technologies (K. A. EHRICKE) .................................. 144
Chapter 13. Entry PropUlsion and Power Systems
Technology (R. W. BUSSARD) ...................................................... 182
Chapter 14. Guidance and Control for Atmospheric
Entry (R. C. DUNCAN) ................................................................ 205
Chapter 15. Dynamics of Planetary Approach
(W. T. THOMSON) ........................................................................ 257
Part Five. Advanced Entry Programs
Chapter 16. Entry Research and Development
Program Management (J. F. Shea) .............................................. 282
viii
I
Summary Discussion on Re-entry
and Planetary Entry-Physics
and Technology
W.H.T.LOH
Manager, Science and Technology,
Space Division,
North American Aviation, Inc.,
Downey, California.
[1-1] INTRODUCTION 1,2, a, 4
The final problem associated with space flight, interplanetary travel or
satellite orbit is the physical recovery or survival of the vehicle and its pay
load (personnel, instruments, and so on) on the Earth surface or planetary
surface. For atmospheric planets, the problem involves essentially decelera
tion, aerodynamic heating and control of the time and location of landing.
For non-atmospheric planets, the problem essentially involves only decelera
tion and control of the time and location of landing. A general description
of atmospheric and non-atmospheric planetary entry precedes the analyses
of the problem.
A vehicle approaching Earth or planetary atmosphere from space or from
orbit possesses a large amount of kinetic energy due to its speed, and poten
tial energy due to its position above the Earth or planet. When it encounters
the atmosphere, a shock wave will form ahead of the nose of the vehicle,
heating the atmosphere in this region to a very high temperature. As the
vehicle plunges into a deeper and denser atmosphere, the vehicle will in
creasingly be heated by this enveloping layer of incandescent atmosphere,
while the speed of the vehicle will continuously be reduced by the braking
force of the atmosphere. It is in this manner that the vehicle's kinetic energy
is converted into heat. If all the vehicle's energy were converted into heat
energy within the vehicle itself, it would be more than enough to vaporize
the vehicle, its payload and any cooling system it could carry. However, the
2 He-Entry and Planetary Entry
natural survival of meteorites is physical evidence that not all of the energy
appears within the body itself. Actually a large part of the total energy is
diverted away from the vehicle. There are essentially two ways to accom
plish this. The first is to unload a major part of the heat on the atmosphere
by the action of strong shock waves. The second is to radiate heat away from
the hot surfaces of the vehicle.
The diversion of heat by a strong shock wave is the result of molecular
interactions in the gas around the vehicle. When molecules strike the for
ward surface, they bounce back. Many of the rebounding particles collide
with oncoming molecules, diverting them from the surface and preventing
them from heating it by direct impact. The high-pressure, high-temperature
buffer layer in which this happens is bounded on its forward surface by the
shock wave. The wave extends a considerable distance into the atmosphere
on either side of the body, leaving a broad wake of heated gas that contains
a major portion of the total heat load. The heat that does reach the vehicle
comes from the shock layer, mainly by friction. The fraction of the total
energy that appears as frictional heat in the body depends upon the charac
teristics of the flow around the body. A blunt nose produces the strongest
shock waves. Since the fraction of the total heat load that is transferred to the
atmosphere is directly proportional to the strength of the shock wave, the
stronger the shock wave, the smaller the frictional component introduced into
the body. For this reason an entry vehicle is given a blunt shape rather than the
slender, streamlined configuration that has been the classic solution to aero
dynamic problems at lower speeds. Figure 1-1 further illustrates this effect.
At higher speeds and higher temperatures, however, radiation and con
vection from the shock layer will constitute a substantial portion of the heat
transferred to the body. This is schematically illustrated in Figure 1-2.
At the present time, the heat that reaches the vehicle can be dispersed by
one or more of the following methods.
The first method is simply to absorb the entire amount of heat by making
the skin material thick enough to act as a heat sink, provided the allowable
skin-temperature limit of the material is not exceeded. In the case of ballistic
or steep-angle entry into atmosphere, the vehicle reaches the lower and
denser atmosphere in a very short time. The deceleration is accomplished
during this short period. Consequently, the heating rate, or heat transferred
into the vehicle per unit time, is very large. However, since the deceleration
time is short, the total amount of heat transferred to the vehicle during the
entire deceleration may not be excessive. In such a case a blunt-nosed, thick
skin, heat-sink-type heat shield may be used. The disadvantage of this
method is that the low heat capacity of most metals imposes a considerable
weight penalty.
Summary Discussion-Physics and Technology 3
On the other hand, when shallower, lifting entry into the atmosphere is
desired, the time to reach the lower and denser atmosphere is longer. The
deceleration is essentially accomplished at very high altitudes. Consequently,
at high altitude and low density, the heating rate or heat transferred into the
vehicle per unit time is small. When the heat transferred into the vehicle per
unit time is small enough so that the rate of heat transferred into the vehicle
can be made eventually equal to the rate of heat radiated by the surface of
Fig. 1-1. Strength of shock wave (black curves) determines the heat and drag applied
directly to the vehicle by air friction. Slender shape creates weak shock wave and therefore
a heavy frictional layer (white area). Blunt shape has strong shock and little friction.
(After Becker, Ref. 1.)
the vehicle, a radiation-cooled shield with a thin-metal skin and negligible
heat sink capacity may be used as the second method of dispersing heat. The
only proviso is that the skin temperature in this radiation-equilibrium situa
tion must not exceed the heat capacity of the metal. If present surface tem
perature requirements are to be met, deceleration must occur at a very high
altitude, necessitating a high lift-drag-ratio vehicle with a high gross weight.
The third method is to use a heat shield constructed of insulating layers
of fiberglass and similar materials, properly applied and bonded. Under
intense heat, the outer layer of the shield chars, melts and vaporizes. This
process, known as ablation, in itself absorbs a good deal of heat. In addition,
the vaporized material tends to block the flow of heat from the hot shock
layer into the body. The combined effects result in a very high heat capacity
of 5,000 btu per pound or more. With present ablation materials, a heat
shield for a ballistic satellite vehicle or even for a lunar return vehicle ap
pears definitely within reach. At the present time, the ablation heat shield
is also one of the lightest and certainly is the simplest solutions of the entry
problem that can be achieved.