U.S. patent number 3,773,574 [Application Number 04/630,562] was granted by the patent office on 1973-11-20 for rocket propellant composition including human body generated waste materials.
This patent grant is currently assigned to Rocket Research Corporation. Invention is credited to Robert M. Bridgforth, Jr., Carl D. Good, George S. Sutherland.
United States Patent |
3,773,574 |
Bridgforth, Jr. , et
al. |
November 20, 1973 |
ROCKET PROPELLANT COMPOSITION INCLUDING HUMAN BODY GENERATED WASTE
MATERIALS
Abstract
A system and method for utilizing and disposing of carbonaceous
waste products accumulated aboard a spaceship, including human body
generated wastes and other carbonaceous wastes, by processing the
waste products into rocket propellants and utilizing such
propellants for spaceship propulsion. The propellant compositions
thus formulated are characterized by the presence of one or more
fuel constituents and one or more inorganic oxidizer constituents
(e.g., ammonium nitrate) in homogeneous admixture with the human
body generated waste materials (e.g., human excrement).
Inventors: |
Bridgforth, Jr.; Robert M.
(Mercer Island, WA), Sutherland; George S. (Mercer Island,
WA), Good; Carl D. (Seattle, WA) |
Assignee: |
Rocket Research Corporation
(Seattle, WA)
|
Family
ID: |
24527670 |
Appl.
No.: |
04/630,562 |
Filed: |
April 13, 1967 |
Current U.S.
Class: |
149/22; 149/37;
149/41; 149/43; 149/18; 149/40; 149/42; 149/44 |
Current CPC
Class: |
B64G
1/60 (20130101); C02F 11/00 (20130101); C06B
23/00 (20130101); C02F 2103/005 (20130101); C02F
2201/001 (20130101) |
Current International
Class: |
C02F
11/00 (20060101); B64G 1/60 (20060101); B64G
1/22 (20060101); C02F 9/00 (20060101); C06B
23/00 (20060101); C06d 005/06 (); C06d
005/10 () |
Field of
Search: |
;149/18,19,44,109,22,37,41,42,43 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Padgett; Benjamin R.
Claims
What is claimed is:
1. A rocket propellant comprising a mixture of:
fuel constituents, including human body generated waste products
and one or more metallic fuels; and one or more inorganic
oxidizers, such oxidizers being of a nature and present in an
amount sufficient to combustively react with said fuel
constituents.
2. A rocket propellant mixture according to claim 1, wherein said
human body generated waste products include human excrement.
3. A rocket propellant mixture according to claim 2, wherein said
human excrement relatively comprises between about five percent and
about 65 percent of the weight of the mixture; the metallic fuel
relatively comprising between about 10 percent and about 40 percent
of the weight of the mixture; and the oxidizer relatively
comprising between about five percent and about 50 percent of the
weight of the mixture.
4. A rocket propellant mixture according to claim 2, wherein said
human excrement comprises about 30 percent of the weight of the
propellant mixture; the metallic fuel comprising about 20 percent
of the propellant mixture; and the oxidizer comprising about 45
percent of the weight of the mixture.
5. A rocket propellant mixture according to claim 1, wherein said
metallic fuel is selected from the group consisting of aluminum,
beryllium boron, and mixtures thereof.
6. A rocket propellant mixture according to claim 5, wherein said
metallic fuel comprise aluminum powder.
7. A rocket propellant mixture according to claim 1, wherein said
inorganic oxidizer is selected from the group consisting of
ammonium nitrate, ammonium perchlorate, alkali metal perchlorates
and mixtures thereof.
8. A rocket propellant mixture according to claim 7, wherein said
inorganic oxidizer comprise ammonium nitrate.
9. The propellant mixture according to claim 2, wherein the human
body generated waste products include human feces.
10. The propellant mixture according to claim 2, wherein said human
body generated waste products include human urine.
11. A rocket propellant mixture according to claim 4, wherein said
human excrement comprises about one-third human urine and about
two-thirds human feces, by weight.
12. A rocket propellant mixture according to claim 4, and further
including carbon particles comprising about five percent of the
weight of the propellant mixture.
13. A rocket propellant composition, comprising a mixture of about
20 percent aluminum, about 45 percent ammonium nitrate, about 10
percent human body generated urine, about 20 percent human body
generated feces, about five percent bone black carbon and less than
about one percent gellant.
Description
BACKGROUND OF THE INVENTION
The present invention relates generally to waste disposal and
propulsion systems for manned spacecraft. More particularly, this
invention provides an integrated system and method for (a)
collecting the various wastes generated during a manned space
mission, including human wastes, (b) processing the wastes to
produce a propellant composition, and (c) burning the propellant so
formulated in the rocket propulsion system of the spacecraft,
thereby simultaneously disposing of the wastes and adding to the
thrust generating capability of the spacecraft propulsion system.
The present invention also relates to novel rocket propellant
compositions which include human waste products.
One serious problem in the field of manned space travel is the
disposal of the various wastes, including human wastes, which are
generated during an extended manned space flight. If the wastes
generated during the mission must be stored in the spacecraft, they
will contribute to the dead weight, and increase the propulsion
requirement of the spacecraft. Moreover, a system must be provided
in the spacecraft for inhibiting the growth of bacteria in the
waste collected to maintain a sanitary spacecraft environment,
thereby creating additional weight and power requirements for the
vehicle. Thus, not only are the waste products not used
efficiently, but they create an additional burden on the limited
thrust capability of the spacecraft.
The periodic dumping overboard of the wastes generated during tbe
mission can alleviate the weight problem somewhat, but means must
still be provided for sterilizing the waste before expelling it
into space. Moreover, this method does not make efficient use of
the wastes.
Another problem in the development of manned space travel is how to
provide a manned spaceship with a sufficient quantity of propellant
for an extended flight without adding excessive weight to the
vehicle. Manned space missions must often be terminated sooner than
desirable because of the limited supply of propellant which can be
carried by the spaceship.
SUMMARY OF THE INVENTION
It is a basic object of this invention to provide a more efficient
system and method for disposing of the waste products generated
during a manned space mission.
Another object of the present invention is to provide a system and
method for increasing the propellant supply aboard a manned
spacecraft without adding to the weight of the vehicle.
A further object of the present invention is the provision of a
system and method for utilizing the wastes generated during a
manned space mission as a constituent of a rocket propellant.
Still another object of this invention is the provision of an
integrated system and method for collecting and treating the human
body generated waste products generated during a manned space
flight to form a rocket propellant which may be utilized on board
the vehicle to incrase the propulsion capabilities thereof, thereby
permitting extended manned space missions.
Yet another object of the present invention is to provide a rocket
propellant which includes human body generated waste products as a
significant ingredient.
Another object of this invention is to provide a relatively
inexpensive rocket propellant.
The foregoing objects have been realized by providing an integrated
waste management/rocket propulsion system aboard a spacecraft,
which system includes human body generated waste products
collection and storage means, and means for mixing the collected
waste products with suitable propellant fuel and oxidizer
additives. The fuel-oxidizer-waste mixture may then be delivered to
the propulsion motors of the vehicle where it is burned as fuel,
thereby simultaneously disposing of the wastes and adding to the
propulsion capabilities of the vehicle.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects, features, advantages, and characteristics of the
present invention will become apparent in the following description
of certain embodiments of the invention, taken together with the
accompanying drawings, wherein like reference characters designate
like parts, and wherein:
FIG. 1 is a diagrammatic and schematic illustration of an
integrated waste management/rocket propulsion system according to
the present invention and provided with hydraulic means for
transferring the waste products collected between a waste collector
tank, a storage tank, and a propellant preparation tank;
FIG. 1A is a block diagram showing the water cycle which may be
utilized in a spacecraft having a waste management/rocket
propulsion system of the type shown in FIG. 1;
FIG. 2 is a diagrammatic and schematic illustration of another
embodiment of a waste management/rocket propulsion system according
to the present invention, adapted for use on an extended space
mission wherein the used wash water and urine generated during the
mission are reclaimed and treated for reuse;
FIG. 2A is a block diagram showing a water cycle which may be
utilized on a space vehicle which includes a integrated waste
management/rocket propulsion system shown in FIG. 2; and
FIGS. 3-9 are various graphical presentations which are referred to
hereinafter in analyzing various properties of certain rocket
propellants formulated by the systems illustrated in FIGS. 1 and
2.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 depicts an integrated waste management/propulsion system 20
typifying the present invention and particularly suitable for use
on a manned spaceship (not shown) whose mission does not require
that the generated liquid wastes be reclaimed and treated for
reuse. Waste management/ propulsion system 20 comprises a waste
collector tank 22 into which the various waste products generated
are initially deposited, a storage tank 24 which receives the waste
products from the waste collector tank 22, either before or after
admixture thereof with the fuel-oxidizer constituents, and stores
them for a prescribed period of time depending upon the propulsion
requirements of the spaceship, and a propellant preparation tank 26
which receives the waste products either from the collector tank 22
or from the storage tank 24 and also receives suitable fuel and
oxidizer additives from a fuel storage tank 28 and an oxidizer
storage tank 30. The waste collector tank 22, storage tank 24,
propellant preparation tank 26, fuel storage tank 28 and oxidizer
storage tank 30 are interconnected by a hereinafter discussed
network of hydraulic transfer lines and products handling stages,
which network comprises a grinder unit 31, pumping units 32, 34,
transfer mechanisms 36, 38, and mixing units 40, 42.
The waste collector tank 22 receives such solid, carbonaceous
wastes as human feces; food wastes, including the food packaging
material, personal hygiene wastes such as towels, sponges,
detergents, toothpaste, hair and nail clippings, etc.; and such
miscellaneous wastes as carbon from the spacecraft's
atmosphere-regeneration systems, evaporator wicks, condenser wicks,
chemical additives and used charcoal from the spacecraft's air
purification systems. Liquid carbonaceous wastes such as urine and
used wash water are also discharged into the waste collector tank
22 from a separate collector 48 and an associated valve 50 which
permits a portion of the liquid wastes to be recovered from
physiological sampling and analysis or treated for reuse in the
spacecraft. Of course, any or all of the solid and liquid wastes
may be collected singly or collectively, depending upon the
disposition to be made of the wastes. If no recovery of the urine
or used wash water is required in the spacecraft, the liquid
collector 48 may be eliminated and the liquid wastes may be
deposited in the waste collector tank 22 at the same point as the
other wastes. Means defining a waste inlet opening 52 is provided
on top of the collector tank 22 and may include suitable means,
such as a toilet seat (not shown), to facilitate the input of human
feces.
Since the waste collector tank 22 will be operating under zero "g"
or partial "g" conditions, pneumatic force or some other positive
method of collecting the various wastes is required. Accordingly,
the waste collector tank 22 in the FIG. 1 embodiment is designed to
utilize cabin atmospheric gas (hereinafter referred to simply as
air) to collect the waste products by eductor action while
preventing contamination of the vehicle atmosphere. The waste
collector tank 22 has a vortex tube design which includes a
reduced-diameter upper section 54 having an air inlet orifice means
56 and an enlarged-diameter lower section including an air outlet
orifice means 58 in the upper portion thereof, and a storage
chamber 60 beneath the gas outlet means 58.
By virtue of the vortex design of the waste collector tank 22, the
wastes entering the collector are given both a downward velocity
which carries them to the bottom of the storage chamber 62, and a
tangential velocity which induces a centrifugal force to separate
the entrained gases from the solid-liquid waste mixture.
The waste may be directed into the storage chamber 62 of the waste
collector tank 22 by aerodynamic drag instead of the eductor action
method described above. However, the eductor action process
provides more positive separation.
A cylindrical surface-tension baffle 64, fastened to the bottom of
the waste collector tank 22, serves to stabilize the solid-liquid
and gas interface of the wastes deposited in the tank, thereby
maintaining the separation of the gas phase from the solid-liquid
mixture and insuring that only the solid-liquid mixture will enter
the grinder unit 31. Zero "g" tests conducted on a spacecraft fuel
tank having a surface-tension baffle comparable to baffle 64 have
shown that such a baffle is effective in maintaining a stable
interface. In this regard, see Petrash, D.A. et al, "Effect of the
Acceleration Disturbances Encountered in the MA-7 Spacecraft on the
Liquid Vapor Interface in a Baffle Tank During Weightlessness,"
NASA Publication TN D-1577, for example.
The steady state configuration of the waste collector tank 22 is
one in which the baffle 64 is completely full, and the remaining
wastes are uniformly distributed at the base of the baffle. During
the flight tests on the fuel tanks referred to in the preceding
paragraph, it was observed that this configuration was independent
of any initial misalignment of the baffle axis with the gravity of
the thrust vector. Moreover, these tests established that the
acceleration imposed upon the experimental tank during orientation
maneuvers in orbit had no effect on the liquid-vapor interface
configuration.
The gas phase of the waste products deposited in the waste
collector tank 22 is removed from the tank by means of a blower 66
cnnected to the air outlet orifice means 58 in the waste collector
tank lower section 60. The gas-contaminated air from the tank 22
passes through a charcoal and membrane filter unit 68 which
decontaminates the air and sends it back into the cabin air supply.
Thus, the FIG. 1 embodiment system includes what may be termed a
semi-closed gas loop.
A hydraulic transfer line 70 connects the tank 22 to grinder 31 and
hydraulic transfer line 71 connects the pumping unit 32 and mixing
unit 40 to a grinder 31, which is provides at the outlet in the
bottom of the waste collector tank 22 to reduce the solid waste
products passing therethrough to a sufficiently small size to pass
through the system's transfer lines. The transfer line 70 includes
an inlet and 72 located concentrically within the baffle 64 and
extending above the bottom of the tank to insure flooded suction
and prevent gas from being drawn into the mixing unit 40.
Preferably, a biostatic agent is introduced into the waste
collector tank 22 as at 74 and is mixed with the collected waste
products to prevent bacterial action and gas production during
storage. Alternate methods of treating the wastes include vacuum
drying, refrigeration, high temperature treatment and hermetical
sealing. However, the drying process inherently removes water from
the wastes which must be used in the hydraulic transfer system
(discussed below), and the refrigeration, high temperature and
drying methods require costly power for operation. Thus, these
three methods are presently considered to be impractical. The time
period during which the waste products must be stored prior to
transfer to the preparation tank and propulsion motors will, of
course, be an important consideration in selecting the optimum
waste preservation method.
The storage tank 24 also contains a cylindrical surface-tension
baffle 76 which is similar to the baffle 64 of the waste collector
tank 22 for maintaining effective liquid-solid and gas phase
separation. The storage tank 24, the waste collector tank 22 and
the preparation tank 26 are interconnected by a series of hydraulic
transfer lines 70, 80, 82, 84, 86, 88, 90, 92, 94, 96 and 98 with
associated pumping units 32, 34, mixing units 40, 42, and
selectively operable valves 100, 102, 104, 106, 108, 110, 112, 114
and 116, which permit selective recycling of the waste and
propellant mixtures at various stages of the waste processing
operation in a manner described more fully below.
The fuel storage tank 28 and the oxidizer storage tank 30 are
connected to the preparation tank 26 through transfer lines 120 and
122, respectively. Line 120 includes a suitable transfer mechanism
36 such as a screw conveyor, and line 122 includes a like transfer
mechanism 38.
In typical operation, with waste products at the bottom of waste
collector tank 22, valve 104 in the transfer line 70 is opened and
the pump 32 and mixing unit 40 are turned on to suction the waste
products through the grinder unit 31 and the associated transfer
line, to mix the products into a substantially homogeneous,
slurry-like mixture. In order to obtain a homogeneous mixture, it
may be necessary or desirable to recycle the waste products through
the mixing unit 40 several times, depending upon the nature of the
waste products collected. This may be accomplished by opening the
valves 100 and 104 while holding the remaining valves in the system
closed, whereby the pumping unit 32 causes the waste mixture to
cycle through the lines 80 an 82, waste collector tank 22, line 70,
grinder unit 31, line 71 and mixer 40.
When the waste mixture has recycled through the mixing unit 40 a
sufficient number of times to obtain the desired degree of
homogeneity, valve 100 is closed and valve 102 is opened so that
the pumping unit 32 pumps the waste mixture into the storage tank
24 where it is stored until needed for use in the spacecraft
propulsion motors. The mixture in the storage tank should be used
as it is accumulated, to the extent possible, to fulfill the
spacecraft's propulsion system requirement, since this will
minimize the size and weight requirements for the storage tank 24
and the other various units of the system 20, as well as the weight
of the waste carried by the vehicle. Of course, other parameters,
such as the power requirements of the spacecraft, also need to be
considered in determining the optimum waste load which the storage
tank 24 is designed to carry, and the frequency with which the
mixture in the storage tank needs to be transferred to the
preparation tank 26 and the propulsion motors of the vehicle.
Depending upon the amount of time the waste mixture must be stored
in the storage tank 24, it may be desirable to recycle the mixture
from the tank 24 through the mixing unit 40 one or more times prior
to delivering it to the propellant preparation tank 26. For this
purpose, transfer line 88, including valve 106, is provided. When
it is desired to recycle the waste mixture from the tank 24 through
the mixing unit 40, the valves 102 and 106 are opened, the
remaining valves in the system are held closed, and the pumping and
mixing units 32 and 40 are turned on. The mixture from the storage
tank 24 then is pumped through transfer lines 86 and 88, mixing
unit 40, line 80 and 84, and back to the storage tank 24. The
mixture may then be pumped from the storage tank 24 to the
propellant preparation tank 26 by opening the valve 108, 110 and
114 while holding the remaining valves in the system closed, and
turning on the pumping and mixing units 34 and 42. The pumping unit
34 then pumps the mixture from the waste storage tank 24, through
transfer line 86 and 90, mixing unit 42, and lines 94 and 92, to
the preparation tank 26.
Suitable fuel and oxidizing agents, such as aluminum powder and
ammonium nitrate, respectively, are introduced into the propellant
preparation tank 26 from their respective storage tanks 28, 30 via
transfer lines 120, 122 and transfer mechanisms 36, 38,
respectively. Valves in the system are held closed, and the pumping
and mixing units 34 and 42 are turned on to cycle the
waste-fuel-oxidizer mixture from the propellant preparation tank
26, through transfer line 98, mixing unit 42, transfer lines 94 and
92 and back to the preparation tank 26 a sufficient number of times
to form a homogeneous propellant mixture.
When the waste-fuel-oxidizer mixture has cycled through the mixing
unit 42 a sufficient number of times to form a homogeneous
propellant mixture, the valves 116 and 112 are opened and the
remaining valves in the system are held closed, whereupon the
pumping unit 34 pumps the propellant mixture from the propellant
preparation tank 26, through transfer lines 98, 94 and 96 to the
reaction propulsion motor means provided on the spacecraft for
burning this propellant mixture.
The waste products and fuel-oxidizer transfer and storage system
shown in FIG. 1 also permits admixture of the waste products with
some or all of the fuel or oxidizer, or both, prior to storage in
the storage tank 24. Immediate mixing of waste products having a
relatively high solids content with ammonium nitrate, prior to
storage of the waste products, has been found to be particularly
advantageous from the point of view of handleability and
storability of the waste products, since the ammonium nitrate
promotes liquification of (i.e., fluidizes) certain waste products
solids. Thus, to accomplish an immediate ammonium nitrate addition
to the waste products for example, an ammonium nitrate can be added
directly to the waste collector tank 22 or a pre-mix rich in
ammonium nitrate can be maintained in preparation tank 26 and
transferred therefrom by pump 34 to the input line 88 of pump 32
via line 99 and valve 117. The mixture recycling through pump 32
and tank 22 can then be transferred to the storage tank 24 or can
be recirculated through the tanks 24, 26 with additional fuel and
oxidizer makeup as desired in the final propellant mix. In this
mode of propellant preparation, no raw waste products need be
stored for any appreciable time and the mixes in storage tank 24,
and in preparation tank 26 as well, can be the final propellant
blend or any intermediately mixed variation thereof which may be
desired under any particular operational conditions.
The pumping and mixing units 32, 40, and 34, 42 are suitably in the
form of one or more rotary screw conveyors in the respective
transfer lines which perform the dual function of pumping and
blending the mixtures circulatory therein. Alternatively, the
pumping and mixing units may be separate, independently operable
units, if desired.
As noted above, the system 20 in the FIG. 1 embodiment of the
invention is particularly adapted for use in space vehicles having
missions which do not require that spent wash water and urine
generated during the flight be reclaimed and treated for reuse by
the crew members. Such a mission typically can be a short term
mission of 30 days, for example. For such a mission, it is
contemplated that fuel cells will be used for the generation of
electrical power.
Referring to FIG. 1A, which illustrates a semi-closed water
recovery system which may be employed in conjunction with the
system of FIG. 1, it is seen that condensate from the fuel cells
and the environmental control system of the spacecraft may be
passed through suitable charcoal filter units 128 and 130 and
selectively operable valve means 132 to potable and wash water
storage units 134 and 136, respectively, and for reuse by the crew.
Benzalkonium chloride (BAC) is added to the wash water, as shown in
FIG. 1A, for disinfectant purposes, in a manner conventional per
se.
The modified integrated waste management/propulsion system 150
illustrated in FIG. 2 is particularly suitable for use on a
spacecraft having a mission which requires that the used wash water
and urine generated during the flight be reclaimed, treated and
reused by the spacecraft personnel. Since the liquid content in the
solid waste products collected during such a mission may be
insufficient to act as a transport medium for a hydraulic transfer
system such as used in the FIG. 1 system, it is deemed advisable to
combine the waste collection and storage functions into a single
unit and to provide alternative means for mixing the wastes
collected and transferring them to the spacecraft propulsion
system.
Accordingly, the integrated waste management/propulsion system 150
of FIG. 2 comprises a combination waste collector-storage tank 152
into which are deposited such carbonaceous waste products as human
feces, food wastes, personal hygiene wastes, carbon from the carbon
dioxide reduction system of the spacecraft, evaporator wicks,
chemical additives and charcoal from the spacecraft's air
purification system. Like the waste collector tank 22 shown in FIG.
1, the combination waste collector-storage tank 152 in the
embodiment shown in FIG. 2 has a vortex tube design which includes
a reduced-diameter upper section 154 having air inlet orifice means
156 and an enlarged-diameter lower section 158 having air outlet
orifice means 160 in the upper portion thereof. By virtue of this
vortex tube type design, the various waste products entering the
collector-storage tank 152 are given both a downward velocity to
carry them to the bottom of the tank, and a tangential velocity
which creates a centrifugal force to separate the entrained gases
from the solid waste products.
The gases are removed from the tank 152 by means of a centrifugal
blower 162 connected to the outlet orifice means 160. The
gas-contaminated air from the tank 152 passes through a charcoal
and membrane filter unit 164 which decontaminates the air and sends
it back into the cabin environmental control system. Thus the FIG.
2 system includes what may be termed a closed gas loop.
A biostatic agent is preferably introduced into the waste
collector-storage tank 152 as at 166 to prkvent bacterial growth
therein.
The waste collector-storage tank is further provided with means
defining a waste inlet opening 168 having suitable means, such as a
toilet seat (not shown), connected thereto for facilitating the
input of human feces. In addition, quick disconnect type fittings
170 and 172 are provided as part of the air inlet orifice means 156
and the air outlet orifice means 160, respectively, to permit the
tank 152 to be removed from the system.
Periodically, either when the waste collector-storage tank 152
becomes about half full (for example), or when the waste products
therein are needed for additional fuel for the spaceship propulsion
system, the tank 152 is disconnected from the system via the quick
disconnect fittings 170 and 172 and manually or otherwise moved to
a mixing location. At this location, reaction nozzle 174 is placed
over the open end 168 of the tank 152 and suitably affixed thereto
as by bolts 175. The agitator 180 of a mixer unit 176 is then
inserted through the nozzle 174 into the waste. Suitable fuel and
oxidizer additives, such as aluminum and ammonium nitrate,
respectively, are added to the waste from suitable sources (not
shown), via suitable transfer mechanisms 182, 184, such as screw
conveyors, as diagrammatically shown in FIG. 2. The
fuel-oxidizer-waste mixture is then blended to a substantially
homogeneous mixture, and the mixer unit 176 removed.
The assembly 152, 174 is then relocated to storage, or moved
directly to the propulsion section of the spacecraft, and a
suitable pyrotechnic or like igniter (not shown) is there installed
at the exposed surface of the propellant, whereupon the unit is
ready for firing on demand.
A above noted, the integrated waste management/propulsion system
150 shown in the FIG. 2 embodiment is considered particularly
useful on a spacecraft having an extended mission which requires
that the used wash water and urine generated during the flight be
recovered, treated and reused by the spacecraft personnel. Such
liquid reclamation requirements may be present, for example, during
a mission of 90 days or more. FIG. 2A illustrates, in block diagram
form, a closed water recovery system which may be employed on such
a mission, in conjunction with the integrated waste
management/propulsion system 150 of FIG. 2. Condensate used wash
water, and urine generated during the mission are collected in a
central unit 186, and fed to separate water recovery and treating
units 188 and 190 where the liquids are treated for reuse as wash
water and potable water. It is contemplated that a solar dynamic or
isotope dynamic power source will be employed on spacecraft having
such extended missions. For environmental control, the craft can
also employ a Bosch CO.sub.2 reduction system, such as disclosed in
a technical report entitled "Carbon Dioxide Reduction Systems,"
presented by Martin Mackline at the AIAA 4th Manned Space Flight
Meeting, held at St. Louis, Missouri, on Oct. 11-13, 1965, for
example.
It has been noted above that aluminum powder is a suitable fuel
additive and that ammonium nitrate is a suitable oxidizer additive
for the integrated waste management/propulsion systems of FIGS. 1
and 2. Other fuels, such as beryllium or boron, for example, are
also suitable for use in either of these systems, either in lieu of
or conjunctively with the aluminum and ammonium nitrate
fuel-oxidizer mix above discussed.
It is apparent from the foregoing that the integrated waste
management/propulsion systems described herein provide numerous
advantages over the present separate waste management and
propulsion systems currently employed on space vehicles. In the
first place, the integrated systems of this invention efficiently
utilize the waste products generated during manned space missions
to provide improved spacecraft propulsion capabilities. Moreover,
they provide more sanitary spacecraft environments by eliminating
large quantities of waste materials. A third advantage of these
systems, weight saving, will be apparent from the weight analysis
which follows the propellant composition discussed below.
The propellants produced by the integrated waste
management/propulsion systems of FIGS. 1 and 2 are quite similar to
a family of monopropellants which have been investigated and
developed at Rocket Research Corporation of Seattle, Washington,
except for the presence and utilization of the waste products.
These monopropellants, unlike most medium and high energy
monopropellants, exhibit a high degree of stability. These
monopropellants are designated by the proprietary term MONEX, and
for simplicity this designation is employed in the following
discussion.
The MONEX family of monopropellants operates on the concept or
principle of a combined heat source and working fluid, wherein the
reaction or combustion is essentially a two-step process. Reaction
between two or more of the constituents, usually a gelled liquid
and a light metal additive, provide the thermal energy release; and
a third component, or working fluid, is decomposed and heated to
provide a low molecular weight exhaust, and hence, high
performance. These propellants, bearing the various designations
MONEX A, B, C and D, are heterogeneous thixotropes which, in
contrast to other high energy monopropellants, can be readily
desensitized without severe reduction in performance
characteristics. They are high density propellants (1.1 to 1.6
gm/cc) and have theoretical specific impulses from about 240
seconds to in excess of 300 seconds (based on a chamber pressure of
1,000 psia). Depending upon the specific formulations, the cost per
pound of propellant is low, and certain of the formulations are of
a non-toxic nature.
Safety of many of the MONEX propellant formulations has been
demonstrated by means of impact sensitivity tests and the JANAF
card gap test, a standard means of determining the sensitivity of
liquid propellants to detonation initiation. This card gap test is
presented in detail in a publication entitled "Liquid Propellant
Test Methods," published by The Liquid Propellant Information
Agency, Applied Physics Laboratory, The Johns Hopkins University,
Silver Spring, Maryland, dated March 1960, for example.
One of the MONEX propellants, MONEX A, is disclosed in copending
Bridgforth et al U.S. Pat. application Ser. No. 340,127, entitled
Stable, High Energy Compositions. MONEX A is a multi-component
propellant consisting basically of powdered aluminum, ammonium
nitrate and water. Numerous tests carried out on MONEX A have
indicated that the propellant can be ignited in a smooth and
reproduceable manner and burns with good combustion efficiency. The
characteristics of two MONEX A formulations are presented below in
Table 1: ##SPC1##
The propellant formulations of the present invention employ
carbonaceous waste products, such as human excrement, carbon
residue from the carbon dioxide reduction system of a spacecraft,
and other carbonaceous wastes such as evaporator wick filters,
paper, and food wastes, in place of the water in the MONEX A
propellant formulations (Table I). For simplicity, waste propellant
formulations of this invention will be referred to hereinafter as
MONEX W.
A typical MONEX W formulation, which amounts to a basic derivative
of MONEX A, is presented below in Table II.
TABLE II
EXPERIMENTAL MONEX W FORMULATION
Composition Weight Percent Aluminum 19.60 Ammonium Nitrate 45.00
Urine 10.00 Feces 20.00 Darco (bone black carbon) 5.00 Guartec
XO-402 (gellant) 0.40
COMPOSITION OF WASTE MATERIAL
Urine Feces* Present in Propellant (weight %) (weight %) (Weight
Percent) Water 93.00 65.00 22.30 Inert 2.00 14.00 3.00 Organic 3.50
14.00 3.15 Nitrogen 1.50 7.00 1.65 * Estimated (based on average
composition of human feces)
A 500 gram batch of MONEX W was fired at the 15 pound thrust level
in an end-burning motor 3.8 inches in diameter and 2.5 inches deep.
The engine was fitted with an ATJ graphite nozzle 0.241 inches in
diameter. The 500 gram thixotropic propellant charge of MONEX W
filled the motor to a depth of 1.4 inches. A 17.5 gram pyrotechnic
bag ignitor (composed of 44% Al, 25% Mg and 31% KClO.sub.4 by
weight) produced rapid and smooth ignition. Combustion was
sustained for 45 to 50 seconds and was accompanied by a brilliant
orange flame and white exhaust plume.
As will be apparent, hypergolic ignition, as by use of ClF.sub.3
can also be used for a MONEX W type propellant.
Three 10-gram samples were extracted from a MONEX W batch as set
forth in Table II, and set aside for ground storage tests. One of
the samples was open to air at 70.degree. F., and the other two
were sealed. After 60 days storage, none of the stored propellants
showed any visible signs of bacterial growth. Visual observation of
the sealed containers revealed that the gel structure had been
maintained during the storage period and that propellant gassing
had not occurred. On the open sample, the water had evaporated and
the ammonium nitrate crystallized out, as expected.
From these tests it appears the MONEX W formulation is a stable
propellant for periods up to 60 days or longer and can be reaidly
ignited in small engines.
The integrated waste management/propulsion systems of FIGS. 1 and 2
produce MONEX W type propellant formulations. The system of FIG. 1
produces what will hereinafter be referred to as a "wet" MONEX W
propellant formulation due to the presence of urine and used wash
water therein. The system of FIG. 2 produces a "dry" MONEX W
propellant formulation because of the low water content waste
products collected therein, the urine and used wash water generated
by the spacecraft personnel being reclaimed and treated for
reuse.
As noted above, "wet" MONEX W derived from the high water content
waste products of the FIG. 1 system is similar to MONEX A. A
trinary plot of theoretical specific impulse (I.sub.sp) for various
MONEX A compositions (with H.sub.2 O as the working fluid) is
presented in FIG. 3 for comparison. Performance data are based on
expansion to sea level and would be higher for expansion to vacuum.
By substituting waste for H.sub.2 O, representative MONEX W
performance curves can be approximated. Addition of the solids (dry
feces, polyethylene containers, and papers, for example) does not
degrate the performance appreciably, since they are organic
materials. It should be noted that specific impulse can be varied
over a wide range by shifting the aluminum (Al), ammonium nitrate
(NH.sub.4 NO.sub.3), and water proportions, thereby permitting
flexibility in selection of propellant combinations. FIG. 5 shows
that formulations containing as much as 50 percent waste (by
weight) produce a specific impulse of 200 seconds. However, since
50 percent of the MONEX W propellant is "free" waste, the effective
I.sub.sp of the MONEX W propellant is much higher than the numbers
presented in FIG. 5. A discussion of the effective I.sub.sp is
presented below.
The integrated waste management/propulsion system of FIG. 1 is
particularly suitable for short term missions, as noted above.
Table III below presented the type and quantity of wastes that are
expected to be collected per day from four men on a typical 30 day
mission.
TABLE III
TYPE AND QUANTITY OF WASTES COLLECTED PER DAY FROM FOUR MEN WASTE
MANAGEMENT SYSTEM NO. 1
Waste Weight, pounds Urine (95% H.sub.2 O) 13.3 Wash Water (
>99% H.sub.2 O) 13.3 Feces Wet Weight 1.32 Dry Weight 0.32
Personal Hygiene Detergent (Benzyl Ammonium Chloride) 0.08 Solids
0.04 Sponges 0.04
While performance of the "wet" MONEX W is very attractive from a
propulsion standpoint for short duration missions, it is not
attractive when excess water is not available, as on extended
missions where the used wash water and urine generated must be
reclaimed and treated for reuse. Table IV below presents the type
and quantity of wastes expected to be collected per day from four
men in a space vehicle on a typical 90 day mission.
TABLE IV
Type and quantity of wastes that are collected per day from four
men in a closed water and oxygen life-support system.sup.2
daily Waste (pounds) Urine Wastes Urine Solids (dry) 0.620 Urine
Solids (wet) 1.24 Food Wastes Packaging (dry) 0.8 Food Wastes (as
H.sub.2 O) 0.64 Feces Wet Weight 1.32 Dry Weight 0.32 Carbon (from
Bosch System) 2.62 Personal Hygiene Detergent (benzyl ammonium
chloride) 0.08 Solids 0.04 Sponges 0.04
In addition, every 90 days the following wastes will also be
collected for a four-man crew:
Wash Water Waste Evaporator wick and chemical additive Condenser
Wick 4.5 Charcoal for vapor (dry weight) Charcoal for condensate
Urine Wastes Evaporator wick and 11.7 chemical additive Condenser
wick Charcoal for vapor 14.0 Charcoal for condensate Personal
Hygiene Wastes Towels 0.5 Dry Wipes 0.11 Atmosphere Control Wastes
Charcoal for 3.5 air purification 2. Personal Communication, J.
Zeff, ARDE, INC., and C. D. King, GD/Convair, August, 1965.
Table V below presents the chemical compositions of the prospective
waste products (from Table IV) collectible from four men during a
90 day mission. ##SPC2##
From the waste data presented in Table V, a composite heat of
formation and waste binder formula was calculated. The composite
binder formula is:
Gram-Atoms/ Element Weight Percent 100 Grams C 61.57 5.126 H 4.62
4.583 O 27.94 1.746 N 2.77 0.198 Na 1.22 .053 Cl 1.88 .053
It has been assumed for calculation purposes that all of the inert
material listed in Table V consists of NaCl; although in reality
only about 78 percent is NaCl, and the remainder is composed of
small amounts of K, S, P, Ca, Fe, Mg, etc.
The composite heat of formation may be determined by dividing the
products into subgroups and the resulting heats of formation are
listed in Table VI.
TABLE VI
HEATS OF FORMATIONS OF WASTE PRODUCT SUBGROUPS
H.sub.f .degree. H.sub.f .degree. Weighted Com- Weight Weight Kcal
Kcal Value ponent lbm Percent /mole /mole Kcal/100 g Carbon 266.9
42.10 0.0 0.0 0.0 Water 147.8 23.31 -68.32 -379.2 -88.4 Urea 32.0
5.05 -79.6 -132.5 - 6.7 NaCl 20.9 3.30 -98.3 -168.2 - 5.6 Organic
166.4 26.24 -30.0 - 22.4 - 5.9 Composite Total -106.6
Organic waste values are based on the composition listed in Table
VII below, which are, in essence, the remainder after the other
four subgroups have been removed from Table V.
TABLE VII
COMPOSITION OF ORGANIC WASTE
Component Weight Weight Percent Gram-Atoms C 117.12 70.40 5.862 H
10.66 6.41 6.359 O 35.91 21.59 1.349 N 2.67 1.60 0.114
if the nitrogen content is assumed to be small, an empirical
formula of C.sub.13 H.sub.14 O.sub.3 describes the organic waste
composition, and a heat of formation of -30 Kcal/mole can be
assumed.
The heats of formation used as input data in determining the
theoretical specific impulse of the Al/NH.sub.4 NO.sub.3 wastes
system are:
Ammonium Nitrate--- 102.11 Kcal/100 gm
Aluminum --0
Waste Products ---106.6 Kcal/100 gm
By considering the waste products as a single composition, and
using the foregoing heat of formation in the propellant performance
calculations, the weight percent of waste products can be varied so
as to provide data plots useful for various missions. Calculations
have been completed in which the percentage of solid waste has been
varied from 30 to 65 weight percent, the weight percent aluminum
from 15 to 35, and the weight percent ammonium nitrate from 5 to
45. The theoretical calculations are based on a chamber pressure of
1,000 psia exhausted to sea level (14.7 psia). These data have been
converted to operation at 500 psia chamber pressure and vacuum
exhaust conditions using the following approximations:
Conversion of chamber pressure from 1,000 psia to 500 psia
Multiply by 0.93
Conversion of back pressure from sea level to vacuum
C.sub.f vac /C.sub.f sea level = 1.89/1.47 = 1.25
Conversion factor = (1.25) (0.93) = 1.162
I.sub.sp (500 Vac) = 1.162 I.sub.sp (1,000 4.7)
The results of these calculations are listed in Table VIII below
and are plotted in FIGS. 4 and 5.
TABLE VIII
THEORETICAL PERFORMANCE RESULTS
Weight Percent I.sub.sp, lbf-sec/lbm Case No. Al AN Binder* 1000 -
14.7 500 - Vac 1 35 30 35 210.3 245 2 35 35 30 217.5 253 3 30 05 65
171.2 199 4 30 15 55 187.9 219 5 30 25 45 202.9 236 6 30 35 35
216.9 252 7 25 10 65 181.1 211 8 25 20 55 196.3 228 9 25 30 45
210.4 245 10 25 40 35 223.8 260 11 20 15 65 180.8 210 12 20 25 55
194.4 226 13 20 35 45 207.5 241 14 20 45 35 220.2 256 15 15 40 45
192.0 223 * Waste Products
Results from these fifteen thermodynamic calculations (Table VIII)
show that moderate theoretical specific-impulse valves can be
obtained from systems containing high solids loading. Only 23.31
percent binder H.sub.2 O was available for propulsion use, and a
large percentage came from non-reclaimable feces water.
Interestingly, 42.1 percent of the binder consisted of carbon. As
shown in FIG. 4, the performance is greatly affected by the
percentages of Al and waste products present. Performance decreases
with an increased aluminum content, due to the lack of oxidizing
agent, and decreases with increased waste percentage. However, the
effective I.sub.sp increases with increased waste percentage. The
determination and assumptions used in determining this effective
specific impulse value are described below in the weight analysis
discussion.
For any given mission, a given amount of waste products will be
available for propulsion, and a given amount of energy, as measured
by the burnt velocity increments, will be required from the
propulsion system. These two factors determine the optimum
propellant formulation. Examples of the manner in which these
optimum propellant determinations may be made are illustrated below
in the weight analysis discussion for a 30-day mission and a 90-day
mission.
In determining the propellant requirements for any given space
mission, the waste products available are first determined from the
selected vehicle/mission analysis. Next, using a calculation
procedure similar to that described above, the propellant
formulation should be optimized so as to make maximum use of the
waste products, and to obtain the highest possible burnt velocity
increment, while carrying the lowest possible weight of aluminum
(or other fuel) and ammonium nitrate or other oxidizer into
space.
The following weight analyses compare the weights of the integrated
waste management/propulsion systems of FIGS. 1 and 2 with
comparable nonintegrated systems. These analyses rely upon the
thermochemical calculations discussed above, and utilize weight and
power estimates set forth in the text below for the waste
collectors, pumps, valves, preparation tanks, mixers, and other
waste management subsystem components.
The exemplary integrated waste management/propulsion systems of
FIGS. 1 and 2 are compared herein to separate, nonintegrated waste
management and propulsion systems burning a storable biopropellant,
N.sub.2 O.sub.4 /Aerozine 50, operating pressure-fed with a
delivered vacuum specific impulse of 290 lbf/sec/lbm.
The two specific missions selected for study in connection with the
integrated waste management/propulsion systems of FIGS. 1 and 2
are: (1) a four-man, 30-day mission without water or CO.sub.2
reclamation, and (2) a four-man, 90-day mission with water
reclamation and CO.sub.2 recirculation systems. The propellant
derived from the waste collected during the first mission is "wet"
MONEX W. The propellant from the second mission is "dry" MONEX W.
The constituents of the wastes utilized in the "wet" and "dry"
MONEX W formulations are tabulated in Tables III and IV above.
The theoretical I.sub.sp of a moderate energy monopropellant (MONEX
A -- 37% Al, 33% NH.sub.4 NO.sub.3, and 30% water) has been
calculated as 242 lbf-sec/lbm at a chamber pressure of 1,000 psia,
exhausting to 14.7 psia, which converts to 303 seconds at a chamber
pressure of 500 psia exhausting to vacuum. Assuming 87 percent
specific impulse efficiency, a predicated delivered I.sub.sp (at
altitude) of 263 IBF-sec/lbm results. A preliminary estimate of the
impulse requirements for orbit adjust (drag makeup) of a 30-day
mission is approximately 150,000 lb-sec. In order to account for
I.sub.sp differences between the competing systems, the impulse
requirement was converted to a .DELTA. V delivered to the vehicle
at a specific impulse of 290seconds. The amount of propellant
required to produce the same .DELTA. V to the same final vehicle
weight, utilizing the MONEX A, was calculated to be 500 pounds.
As noted above, the water content of MONEX A iw replaceable by the
highly liquid waste materials generated by four men during a 30-day
mission. It is calculated that the propellant requirements are 203
pounds of aluminum, 182 pounds of ammonium nitrate, and 165 pounds
of waste material. As shown in Table III above, the total waste
produced by four men in a 30-day mission is approximately 852
pounds, of which 14.4 pounds is solid material. This solid material
and part of the liquid waste will be burned in the propulsion
system. The excess liquid material will be disposed of through the
overboard dump, as would be done in a nonintegrated system. It is
important to note that a greater impulse requirement (.DELTA. V
requirement) would significantly improve the weight advantage of
the integrated waste management/propulsion system of FIG. 1, since
all rather than only part of the liquid waste material would be
utilized to produce impulse.
With respect to "dry" MONEX W, thermochemical calculations for the
aluminum, ammonium nitrate, and dry waste propellant composition
yielded the theoretical performance curves shown in FIG. 4.
Assuming an 87 percent specific impulse efficiency, these numbers
are convertible to delivered specific impulse as a function of
propellant composition, as shown in FIG. 6. To compare the
performance attainable by this propellant combination with the
competing bipropellant system, while simultaneously accounting for
the fact that a specific .DELTA. V is required rather than just a
total impulse, the following technique derives an effective
specific impulse.
Assuming the same .DELTA. V is to be applied to the same final
vehicle weight, the amounts of propellant required by a
bipropellant system delivering a specific impulse of 290 seconds
and a waste management propellant delivering the I.sub.sp shown in
FIG. 6 were determined, and the amount of propellant to be carried
into orbit in order to deliver this .DELTA. V was calculated. This
computed amount of propellant is merely equal to the total
propellant requirements, multiplied by the sum of the weight
percents of aluminum and ammonium nitrate for the particular
propellant composition under study. The ratio of the required
bipropellant weight to this propellant weight, multiplied by the
specific impulse of the bipropellant system (290 seconds), was then
defined as the effective I.sub.sp. Values of the effective I.sub.sp
as a function of propellant compositions for .DELTA. V's of 10,
1,000 and 10,000 feet per second are shown in FIGS. 7, 8 and 9,
respectively.
For purposes of preliminary weight estimates, a propellant
containing 25 percent aluminum, 30 percent ammonium nitrate, and 45
percent waste was chosen as the candidate propellant for the
integrated waste management/propulsion system of FIG. 2. By
referring to FIGS. 7 through 9, inclusive, it is seen that such
composition does not represent the maximum effective specific
impulse attainable. However, because there can be some doubt as to
the combustion characteristics of propellant containing greater
than 45 percent waste material; and since a 45 percent waste
material propellant composition will effectively ignite, this
propellant system has been used for the weight comparison.
Based on preliminary calculations for an extended space mission,
the requirements for spin-up and despin once every 90 days demand a
total thrust of approximately 300,000 pound-seconds. A final
vehicle weight of approximately 10,000 pounds corresponds to a
.DELTA. V requirement of approximately 1,000 feet per second. From
FIG. 8, at a .DELTA. V of 1,000 feet per second, this candidate
propellant is seen to yield an effective I.sub.sp of 380
seconds.
At this specific impulse, 790 pounds of ammonium nitrate and
aluminum are required to mix with the waste material in order to
deliver the total of 300,000 pound-seconds. The total propellant
weight breakdown is thus 360 pounds of aluminum, 430 pounds of
ammonium nitrate, and 646 pounds of waste, for a total propellant
weight of 1,436 pounds.
Based upon the foregoing performance values, the weight comparisons
for the two missions (30 and 90 days) of interest are tabulated
below.
An estimate of the total weight of separate, nonintegrated waste
management and bipropellant propulsion systems for the 30-day
mission has been determined as follows. Assuming the waste
collector tank can contain 4 man-days of waste, a typical waste
management system would weigh approximately 25 pounds. This is
broken down as follows:
Weight, Pounds Waste collection 7 Storage tank 15 Blower 1 Filter
and deodorizer 2
The bipropellant propulsion system weight for the 30-day mission
was calculated based on an assumed I.sub.sp of 290 seconds and a
mass fraction of 0.8, which yields a propulsion system wet weight
of 648 pounds. The combined weight of the two separate systems
totals 673 pounds.
The integrated system weight analysis is based on the following
weight breakdown:
Inert Weight (Pounds) Waste collector 7 Storage tank 15 Preparation
tank 15 Blower 1 Filter and deodorizer 2 Transfer pumps (4) 8
Aluminum storage tank 12 Ammonium nitrate storage tank 14 Plumbing
and pressurization hardware 10 Structure and mounts 26 Valves (13)
10 Water collector 4 Thruster (including valves, lines) 30 Total
154
The combined weight of aluminum and ammonium nitrate to be carried
into orbit is 385 pounds.
The following additional power requirements, above and beyond those
of a normal mission, were assumed:
Transfer pumps (4) --200 watts
Assuming that a fuel cell penalty of 3watts per pound yields a
power system weight penalty of 67 pounds, the total integrated
system weight is 606 pounds.
This comparison, therefore, shows a 67 pound weight advantage to
the integrated waste management propulsion system of FIG. 1, based
upon conservative assumed values. Additional weight savings which
may be realized are discussed below, following the weight analysis
of the FIG. 2 system.
The estimate of the total weight of separate, nonintegrated waste
management and bipropellant propulsion systems for a 90 day mission
assumed a total weight required of 48 pounds. This was made up as
follows:
Weight, Pounds Waste collector unit 45 Blower 1 Filter and
Deodorizer 2 Total 48
Assuming a bipropellant specific impulse of 290 seconds, with a
mass fraction of 0.8, the propulsion system wet weight is 1,295
pounds, and the total weight of the two systems is 1,343
pounds.
The integrated waste management/propulsion system weight analysis
assumed an inert parts weight of 203 pounds, broken down as
follows:
Inert Weight (Pounds) Waste collector (90 units) 45 Blower 1 Filter
and deodorizer 2 Mixer 3 Aluminum storage tank 18 Ammonium nitrate
storage tank 31 Structures and mountings 42 Valves (2) 1 Transfer
Pumps (2) 4 Plumbing and pressurization hardware 6 Propulsion
(including propellant valve, lines, and fittings) 50 Total 203
The weight of aluminum and ammonium nitrate to be carried into
orbit as discussed previously is 790 pounds. In addition, a power
system weight penalty was assessed, based on an assumed value for
fuel cells of 3 pounds per watt. A power penalty of 75 watts for
the mixer, and 100 watts for the two transfer pumps, was assumed,
yielding a total of 175 watts power penalty during operation. On
the basis of 3 watts per pound, this amounts to 58 pounds penalty.
As a result, the total integrated system weight is 1,051 pounds,
292 pounds less than the weight of the non-integrated systems.
The above comparisons show significant weight advantages for the
integrated waste management/propulsion systems, based on
conservative assumptions with regard to performance, storage, and
transfer systems. The effective I.sub.sp as used herein is based
upon delivery of a specified amount of velocity change in the same
final vehicle weight. This assumption does not account for the fact
that the final vehicle weight with the bipropellant system would
have to be increased to allow for the waste which has accrued up
until that time and is being carried on board. In the case of the
30-day mission, assuming the liquid is dumped overboard, this
build-up of waste is negligible (14.4 lb-m). In the case of the
90-day mission with water recirculation, however, the build-up of
solid waste is quite significant (443 lb-m).
Certain components in a vehicle incorporating the integrated system
of FIG. 1, such as instrumentation hardware or tools, may be
fabricated of powderized aluminum, held together with a water
soluble binder, and protected by a disposable coating. These
components could be placed in the aqueous waste mixture in the FIG.
1 collector tank or preparation tank when they were no longer
needed during the mission. The water soluble binder would then
dissolve in the mixture, and the aluminum powder would disperse and
serve as a fuel additive, thereby requiring less aluminum to be
carried by the spacecraft and offering additional significant
weight savings to the vehicle.
If a missile system is designed with the integrated waste
management/propulsion system as the basic design concept, a number
of advantages can be realized. For example, the third stage
boosters or service modules which now remain in orbit can be
designed to provide the necessary fuel and oxidizer material. Many
knobs and panels could be fabricated from nitrocellulose or similar
materials, or from powdered metal, and used as propellant
constituents when the unit in which they were contained had
completed its mission. Organic materials such as the coverings on
electronic components and packing materials could also be
utilized.
The waste management/propulsion system shown in FIG. 1 includes a
water collector and an overboard dump. This is necessary because
the small total impulse requirement assumed does not allow for the
complete utilization of all the water produced in the waste. Should
it be desirable to produce more total impulse, more of this waste
material could be utilized, with significant results in overall
weight savings from any competing systems. FIG. 1 and the weights
allowed in the system comparisons above also include separate gear
pumps for each operation. However, some pumping equipment and
valving arrangements can readily be integrated and optimized so as
to improve the weight efficiency of the system.
From the foregoing considerations, various further modifications,
formulations, and utilization techniques characteristic of the
invention will be apparent to those skilled in the art, within the
scope of the following claims.
* * * * *