Optical inspection probe permits remote inspection of combustion chambers through 360 degrees, and is fully controllable in terms of elevation, focus, and sweep. It eliminates the hazards of physically entering combustion chamber interiors and throats of rocket engines for inspection

Walker, J.

English

NASA Technical Reports Server

May 1969	 Brief 69-10142 
NASA TECH BRIEF	
I Ask, 
NASA Tech Briefs are issued to summarize specific innovations derived from the U.S. space program, 
to encourage their commercial application. Copies are available to the public at 15 cents eaëh 
from the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Improved Combustion Chamber Optical Probe 
Combustion Chamber	 Azimuth Circid 
/ Of Rocket Engine
Elevation View Line 
Elevation Mirror 
Telescoping Jack 
Assembly	 Aluminum Tube 
Cantilevered Beam 
Television Camera
Figure 1 Perspective View of Improved 
Combustion Chamber Optical Probe. 
The development of this optical inspection probe 
should be of interest to technical personnel in the 
aircraft, rocket, and diesel power industries, and to 
manufacturers of instrumentation and optical equip-
ment. The device permits remote inspection of com-
bustion chambers through 360 degrees, and is fully 
controllable in terms of elevation, focus, and sweep. 
This capability represents a meaningful improvement 
over present probes which are quite limited in their
spherical spanning angle, and enables more accurate 
viewing than is currently possible. In addition, the 
hazard of physically entering combustion chamber 
interiors and throats of rocket engines in order to 
inspect them can be eliminated. 
Numerous periscope-type probes have been de-
veloped in the past, but they lacked the capability of 
full hemispherical viewing. Other inspection devices 
have featured a reflecting mirror mounted for rotation 
(continued overleaf) 
This document was prepared under the sponsorship of the Naiional
	 Government assumes any 1iaIility resulting from the use of the 
Aeronautics and Space Administration. Neither the United States 	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States
	 will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19690000142 2020-03-16T17:57:31+00:00Z
about an axis which is perpendicular -to the longi-
tudinal axis of the probe, but in such instances the 
transverse axis did not penetrate the reflective surface 
plane. The hemisphere viewed with such devices is 
always in the general direction that the image is to be 
reflected, and "spherical viewing" is not achieved. 
(Spherical viewing would include the hemisphere in 
the direction toward which the image is to be trans-
mitted, as well as the hemisphere extending away from 
the direction that the image is to be transmitted.) 
'This unique probe includes in combination an azi-
muth mirror and an elevation mirror. The elevation 
mirror is mounted for rotation about an axis which 
is generally transverse to the longitudinal axis of the 
probe. The transverse axis penetrates the plane formed 
by the reflective surface of the mirror. The mirror of 
the probe can be rotated selectively about the trans-
verse axis as well as the longitudinal axis. The device 
receives the reflected image from the elevation mirror 
and transmits the image longitudinally of the probe, 
which may be in the form of an azimuth mirror 
mounted in the probe. 
A perspective view of one form of the invention 
is shown inserted in the combustion chamber of a 
rocket engine. The apparatus consists of an optical 
tracking probe mounted on a telescoping jack assem-
bly. The probe and jack assembly are mounted on a 
cantilevered beam for positioning the probe directly 
under the engine in alignment with the combustion 
chamber of the rocket engine. Operation of the jack 
assembly causes the probe to be raised in the com-
bustion chamber of the rocket engine. The apparatus 
may include a television camera mounted on a beam 
focused to receive the image transmitted by the inspec-
tion probe. The top portion of the probe may be 
provided with lights for adequately illuminating the
combustion chamber and throat. Bulbs can be en-
closed in an explosion proof housing to prevent any 
fire hazard. 
The azimuth position and elevation position of the 
elevation mirror are determined by operation of 
motors. Focusing of an objective lens is also con-
trolled by operation of a motor. By rotating the eleva-
tion mirror, a view can be obtained of all objects that 
lie in the vertical plane passing through the penetra-
tion point of the elevation mirror axis on the eleva-
tion mirror plane. By rotating the probe tube, the 
vertical scanning plane may be positioned selectively 
about the vertical axis of the tube. The combined 
effect of rotating the elevation mirror about both the 
vertical and horizontal axes is that a view may be 
obtained of any object within the desired sphere. 
Note: 
Documentation is available from: 
Clearinghouse for Federal Scientific 
and Technical Information 
Springfield, Virginia 22151 
Price $3.00 
Reference: TSP69-1 0142 
Patent status: 
This invention is owned by NASA, and a patent
application has been filed. Royalty-free, non-exclusive 
licenses for its commercial use will be granted by 
NASA. Inquiries concerning license rights should be 
made to NASA, Code GP, Washington, D.C. 20546. 
Source: Joe Walker
of LTV Aerospace Corporation
under contract to
Manned Spacecraft Center 
(MSC-10953)
is 
. 
Brief 69-10142	 '	 Category 02


Improved combustion chamber optical probe

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