A method is described where a propeller driven, hydrazine powered aircraft is remotely piloted through rarefied atmosphere of a selected planet, including the planet Earth. It is employed as a communication platform for a telemetry system provided for relaying information relating to features characterizing the surface of the planet

Reed, R. D.

English

NASA Technical Reports Server

United States Patent 1191 
Reed 
11 11 4,240,601 
W I  Dec. 23. 1980 
METHOD FOR OBSERVING THE 
FEATURES CHARACXERIZING THE 
SURFACE OF A LAND MASS 
Inventor: 
Assignee: 
Robert D. Reed, Lancaster, Calif. 
The United States of America as 
represented by the Administrator of 
the National Aeronautics and Space 
Administration, Washington, D.C. 
Appl. No.: 43,912 
Filed: May 30, 1979 
Int. C1.3 ........................... B64G 1/62; B64G 9/00 
U.S. C1. ....................................... 244/160, 24/49 
Field of Search ................. 244/49, 158, 160, 162, 
244/138 R;33/1A;358/108, 109 
References Cited 
U.S. PATENT DOCUMENTS 
2,763,447 9/1956 Carrau ............................. 244/1M) X 
-10 
i e  
\ 20-40 H 
SUR FACE 7 \-. CRUl 
3,744,741 7/1973 Christian ............................ 24/49 X 
OTHER PUBLICATIONS 
R. Dale Reed, “High Flying Mini-Sniffer RPV:Mars 
Bound?” Aeronautics and Astronautics. Jun. 1978, pp. 
26-39. 
Primary Examiner-Barry L. Kelrnachter 
Attorney, Agent, or Firm-Monte F. Mott; John R. 
Manning; Paul F. McCaul 
[571 ABSTRACT 
A method wherein a propeller driven, hydrazine pow- 
ered aircraft is remotely piloted through rarefied atmo- 
sphere of a selected planet, including the planet Earth, 
and employed as a communication platform for a telem- 
etry system provided for relaying information relating 
to features characterizing the surface of the planet. 
4 Claims, 13 Drawing Figures 
:-I- 
O”RS/ SE 
F 4 O o o  
https://ntrs.nasa.gov/search.jsp?R=19810008977 2020-03-21T08:52:07+00:00Z
U.S. Patent Dec. 23, 1980 Sheet 1 of 3 4,240,60 1 
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U.S. Patent Dec. 23, 1980 Sheet 2 of 3 4,240,60 1 
U.S. Patent Dec. 23, 1980 Sheet 3 of 3 4,240,60 1 
4,24O,60 1 
1 2 
piloting a slow-speed aircraft through the atmosphere 
thereof. 
It is another object to provide in a method for observ- 
ing features characterizing the surfaces of land masses 
5 for celestial bodies the steps including launching a pro- 
peller driven aircraft into the atmosphere thereof for 
purposes Of acquiring and transmitting data to  a com- 
munication link for ultimate transmission to a receiver 
located on the earth's surface. 
These and other objects and advantages are achieved 
through the use of a method which includes the step of 
flying a remotely-piloted, propeller driven aircraft 
through the atmosphere of a selected celestial body, 
1. Field of the Invention including that of the planet Earth for purposes of ac- 
The invention generally relates to a use of remotely l5  quiring and transmitting data related to the features 
characterizing the surface of the body, as will hereinaf- 
ter become more readily apparent by reference to the 
following description and claims in light of the accom- 
panying drawings. 
DESCRIPTION O F  T H E  DRAWINGS 
FIG. 1 is a pictorial view sequentially depicting a 
2. Description of the Prior Art method wherein an aircraft is launched into the atmo- 
For many years* it has been common practice to sphere above a selected land mass and piloted above its 
obtain data relating to the surface characteristics of 25 surface for acquiring information and transmitting data 
remote land through a use Of cameras, to an orbiting satellite for subsequent transmission to an 
and detectors of various sorts. Customarily, the data is ultimate station located on the earth,s surface. 
acquired utilizing high altitude probes as well as probes FIG, is a pictorial view depicting a typical flight 
subsequently is electronically relayed to an earth sta- 30 in FIG. 
tion. 
Of course, vehicles operating in high altitude and employed in launching the aircraft shown in FIGS. fl y-by modes tend to fail to perform a "close" examina- and 2. tion, while vehicles designed to impact the surface of 
the land mass fail to examine more than the vicinity of 35 
impact which necessarily comprises a relatively small larged scale, of the aircraft shown in the configuration 
illustrated in FIG. 36, rotated 90" with respect to the area on the surface of the planet. 
However, if precise and complete data, relating to the plane Of the drawing. 
surface being examined, is to be collected, it is highly FIG. 5 is a front elevational view of the aircraft illus- 
desirable, if not absolutely necessary, to employ a vehi- 40 trated in 
cle having a capability of transporting sensors, cameras, FIG. 6 is a side elevational view, again on somewhat 
detectors and like equipment at low altitudes ranging of an enlarged scale, of the aircraft in its configuration 
from just above ground level to a few thousand feet in generally in 3c. 
order to assure that desired close surveillance is FIG. 7 is an elevational view depicting a typical air- 
achieved. Additionally, it is necessary that the vehicle 45 foil for the aircraft. 
employed be required to travel at relatively slow FIG. 8 is a cross sectional view of a hydrazine engine 
speeds, for accommodating detailed examination, and employed for Propelling the aircraft, 
DESCRIPTION O F  T H E  PREFERRED remain aloft for periods of relatively long durations 
EMBODIMENT sufficient to render such missions economically practi- cable. Often, the surface to be examined, such as high 50 
mountain ranges found on Earth, or the surface of the Referring now with more particularity to the draw- 
planet Mars, is characterized by wind turbulence and- ings wherein like reference characters designate like or 
/or a rarefied atmosphere. corresponding parts throughout the several views, 
It is therefore the general purpose of the instant in- there is pictorially depicted in FIG. 1 a sequence of 
vention to provide a surveillance method for acquiring 55 steps employed in launching and piloting an aircraft, 
data relating to features characterizing remote surfaces generally designated 10, employed in performing the 
of land masses, employing slow speed, propeller driven method of the instant invention. 
aircraft adapted to be launched into a rarefied atmo- At the outset, it is to be understood that the method 
sphere and remotely piloted above the surface thereof. herein disclosed, generally speaking, makes use of exist- 
60 ing technology. Therefore, the details of the structure 
OBJECTS AND SUMMARY OF T H E  herein described as being employed in performing a 
INVENTION method which embodies the principles of the instant 
It is an object of the instant invention to provide an invention, form no part of the claimed invention. 
improved method of surveillance for closely observing Referring again to FIG. 1, it is noted that the aircraft 
features of land masses. 65 10 initially is launched into the atmosphere above the 
It is another object to provide in a method for observ- surface of a land mass employing an aeroshell 12. The 
ing features characterizing the surfaces of the planets aeroshell 12 preferably includes one of a series of aero- 
including the planet Earth which includes the steps of shells adapted to be ejected from an orbiter in a prede- 
METHOD FOR OBSERVING THE FEATURES 
CHARACTERIZING THE SURFACE OF A LAND 
MASS 
ORIGIN OF T H E  INVENTION 
The invention described herein was made by employ- 
ees of the United States Government and may be manu- 
factured and used by or for the Government for Gov- 
ernment purposes without the payment of any royalties lo 
thereon or therefor. 
BACKGROUND OF T H E  INVENTION 
piloted aircraft for gathering information, and more 
particularly to a method wherein a propeller driven, 
hydrazine powered aircraft is flown through the rar- 
efied and/or oxygen free atmosphere of a planet, includ- 
ing the planet Earth, and employed as a communica- 20 
tions platform for relaying data relating to features 
characterizing the surface of the planet's land mass. 
Operating in fly-by Or impact modes' The acquird data path for the aircraft launched and piloted as illustrated 
FIGS. 3a through 3f illustrate a sequence of steps 
is an On a 'Ornewhat en- 
4. 
3 
4,240,601 
termined sequence. The orbiter, in turn, is adapted to be 
launched from a probe, shuttle craft, or similar vehicle 
of known design. 
Conventionally, aeroshells include a capsule 14 pro- 
tected by an ejectable heat shield 16, FIG. 1. As shown 
in the drawings, the capsule 14 is of a design suitable for 
accepting and confining the aircraft 10 when stowed in 
its compact configuration, as best illustrated in FIGS. 
3u and 36. The heat shield 16 readily is ejected from the 
capsule 14 through the use of explosive bolts and the 
like which, in effect, simply jettison the heat shield at an 
appropriate time into the mission whereby the capsule 
14 is separated therefrom. 
As shown, a simple parachute 18 is attached to the 
capsule 14 for supporting the capsule subsequent to the 
ejection of the heat shield. 
As indicated in FIG. 1, the aircraft 10 is, during its 
flight, in continuous communication with a satellite 18' 
which serves as a data relay station whereby data trans- 
mitted from the aircraft 10 is processed and transmitted 
for subsequent relay to the surface of the earth. A suit- 
able system employing communication links of known 
design is employed for this purpose. 
Turning for a moment to FIGS. 3u through 3fit can 
be seen that the aircraft 10 when launched is suspended 
from the parachute through shroud lines, not desig- 
nated, attached to the aircraft 10 at a suitable location, 
preferably beneath the fuselage at a coupling generally 
designated 20, FIG. 6. As shown, the mass of the air- 
craft 10 is located forwardly of the coupling 20 so that 
the aircraft is suspended by the parachute in a nose- 
downwardly configuration. 
As illustrated, the aircraft 10 is adapted to be folded 
into a compact configuration for storage within the 
aeroshell 12. Consequently, it is necessary to accommo- 
date erectional deployment of the aircraft subsequent to 
its ejection from the capsule 14. Therefore, the aircraft 
10 is provided with suitable hinge and locking pins 
located within the wings of the aircraft sufficient to 
accommodate a folding and unfolding of the wings. As 
should be readily apparent to those familiar with the 
design and operation of aircraft conventional of design, 
various techniques may be relied upon in configuring 
the hinges. For example, it is well known that aircraft 
wings can be folded for stowage and subsequently de- 
ployed through the use of slave cylinders acting about 
hinge pins included in the wings of the aircraft. There- 
fore, a detailed description of suitable hinges and actua- 
tors incorporated in the aircraft 10 is believed to be well 
within the purview of the art and a detailed description 
thereof is omitted in the interest of brevity. 
It suffices to appreciate that the aircraft 10 includes a 
fuselage 22 to which is attached collapsible wings 24 
and axially extensible twin booms 26 provided for sup- 
porting aft control surfaces 28. Moreover, where de- 
sired, the twin booms 26 are of axially extensible tele- 
5 
10 
15 
20 
25 
30 
35 
40 
45 
50 
5 5  
scopic design which further facilitates a collapsing of 
the aircraft into a compact configuration particularly 
suited to be received by the capsule 14. 
airfoil section illustrated in FIG. 7 has reasonable per- 
formance down to wing-tip Reynolds numbers of 
200,000 at altitude. The thickness thereof is sufficient to 
afford adequate wing spar strength. As illustrated by 
the dotted lines of FIG. 7, which represent the configu- 65 
ration of an airfoil for the well known Gossamer Con- 
dor, the profile of the wing indicates that the wing 
passes zero-lift pitching moments. 
While the design of the airfoil is varied as desired, the 60 
4 
The aircraft 10 is powered by a hydrazine engine, 
also of known design. As a practical matter, the hydra- 
zine engine is similar in some respects to known C02 
engines frequently employed for model aircraft. Of 
course, the conventional C02 aircraft engine uses a ball 
valve lifted by a finger on a piston and the C02 is pro- 
vided from a cartridge. 
Hydrazine, of course, can be stored for years, pro- 
duces instant power when pumped through a catalyst 
bed and decomposes in the absence of oxygen. Thus, 
hydrazine engines are particularly suited for use in pow- 
ering the aircraft 10. The hydrazine engine 30 employed 
for powering the aircraft 10 includes a hot gas valve 32 
having a flat seat. A finger, not shown, is provided on 
the valve instead of the piston so that the piston is, in 
effect, flat. This minimizes sliding at the seating area to 
reduce spalling and cut tooling requirements. The entire 
valve operates at the temperature of the working fluid. 
A gas generator 34 is mounted off the engine and 
connected thereto by small tubes, not designated, while 
a tube is used to direct hot gas into a small insulated 
plenum chamber 36 adapted to store enough hot gas to 
supply the cylinder without a serious drop in pressure. 
The gas generator 34, in, practice, comprises a catalyst 
bed which serves to convert liquid fuel to hot gas at 
1700" F. 
A fuel tank 38, slightly pressurized by inert gas, is 
provided for feeding hydrazine into a fuel pump 40 
which raises the pressure of the fuel about 850 psi. The 
hydrazine is then fed through a relief valve, not desig- 
nated, which feeds the hydrazine to the gas generator 
34. When the piston opens the hot gas valve, the hot gas 
is delivered to the piston for establishing the power 
stroke. 
It is noted that the hydrazine engine, herein briefly 
described, is of known design and, therefore, the details 
thereof form no part of the claimed invention. 
Connected to the drive shaft is a two-bladed propel- 
ler constructed of foam covered with Kevlar fabric. In 
practice, the propeller is employed as a pusher in order 
to enhance the observation capabilities of the cameras, 
sensors, protectors and the like comprising the payload 
for the aircraft, preferably located in a pod 44 located 
forward of the center of mass for the aircraft 10. 
In performances of the method herein disclosed, an 
aeroshell 12 containing a capsule confining therein an 
aircraft 10 is projected into the rarefied atmosphere 
above a land mass. A suitable power source, such as 
rocket motors or the like, are employed at a predeter- 
mined altitude above the surface of the land mass for 
separating the aeroshell 12 from the heat shield 16 for 
thus permitting the heat shield to descend to the surface. 
However, a parachute 18 is deployed from the capsule 
14 for purposes of supporting the aircraft 10 in a sus- 
pended relationship therewith. Upon being suspended 
from the shroud lines the aircraft 10 seeks a nose-down 
attitude, due to the fact that the center of mass thereof 
is located forwardly of the point at which the shroud 
lines of the parachute 18 are connected to the fuselage 
22 of the aircraft 10. As the aircraft descends, mecha- 
nisms are activated for purposes of initiating a deploy- 
ment of the wings 24, the twin booms 26 and the aft 
control surfaces 28. Once the wings, booms and control 
surfaces are deployed, the engine 30 is activated, where- 
upon the aircraft 10 is disassociated from the parachute 
18, employing a suitable releasing mechanism, such as 
an explosively activated pin. As a practical matter, the 
propeller 42 may be employed for releasing the para- 
4.240,60 1 ~ 7 -  
5 
chute. The aircraft 10 now drops away from the para- 
chute and attains flying speed above the surface of the 
land mass. As a practical matter, the aircraft 10 may 
employ conventional terrain clearance circuitry for 
assuring that a suitable altitude, such as 2,000 feet, is 
maintained throughout its flight. 
1-2s the aircraft 10 progresses above the surface of the 
land mass, through canyons and the like, as depicted in 
FIG. 2, sensors, cameras, detectors and the like 
mounted in the pod 44 are activated for observing the 
characteristics of the surface being examined. Intelli- 
gence concerning the observed characteristics is then 
transmitted in the form of electronic data to an orbiting 
satellite 18’. While the data thus collected may be trans- 
mitted in real time, where desired, the data also may be 
stored aboard the aircraft for transmission at an opti- 
mum location relative to the surface and/or the satellite 
18’. Finally, of course, the data may be stored aboard 
the satellite for subsequent transmission. 
In any event, it shouid be appreciated that the aircraft 
10 is intended to be operated over extended ranges for 
relatively long periods and studies have indicated that 
where the cruise range is cut in half, for certain atmo- 
spheres, numerous vertical takeoffs and landings may be 
6 
A. deploying from a parachute into the atmosphere a 
propeller-driven aircraft; 
B. piloting the aircraft in a horizontal cruise mode 
above the surface of the body, whereby the aircraft 
is caused to fly over portions of the surface to be 
monitored; and 
C .  monitoring the portions of the surface during the 
flight of the aricraft thereover. 
2. In a method for observing features characterizing 
10 the surface of a land mass of a planet, the steps compris- 
A. launching into an atmosphere above the land mass 
an aircraft folded into a collapsed configuration 
and suspended from a parachute, said aircraft being 
equipped with a propulsion unit including a bladed 
propeller, a reciprocating mono-propellant engine 
for driving the propeller, and electronic observa- 
tion devices; 
E. erecting the aircraft into an air-worthy configura- 
C .  piloting the aircraft through the atmosphere and 
electronically observing the features characteriz- 
ing the land mass; and 
D. transmitting to a station remotely related to the 
aircraft intelligence relating to the observed fea- 
5 
ing: 
15 
20 tion; 
25 
tures. 
3. The method of claim 2 wherein the step of launch- performed for accommodating capture and delivery of 
ing an aircraft into the atmosphere includes the steps of surface objects. 
ent that the instant invention provides for a practical 30 protective aeroshell and expelling the aircraft from the 
surveillance of the surface of a land mass for facilitating aeroshell. 
close-range observation of surface characteristics. 4. The method of claim 3 wherein the aircraft com- 
prises a collapsable aircraft stowed in the aeroshell in a 
collapsed configuration and adapted to be expanded 
In  vleW of the foregoing, it should readily be appar- projecting the aircraft into the atmosphere encased in a 
What is claimed is: 
1. A method for achieving surveillance of the surface 
o f  a celestial body having a rarefied atmosphere com- 35 upon an expulsion thereof from the aeroshell. 
prising the steps of * * * * *  
4s 
50 
5s 
60 
65 


Method for observing the features characterizing the surface of a land mass

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