Single-pane, uncoated windows absorb infrared rays and transmit visible and near-visible wavelengths. Two opposed rod heaters direct infrared rays at the pane, reflectors aid in this heating which prevents condensation. These windows are useful for telescopes and cameras for oceanographic and related studies

Neuman, J. R.

Novoryta, R. J.

English

NASA Technical Reports Server

October 1970	 Brief 70-10324 
NASA TECH BRIEF 
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nology Utilization Division, NASA, Code UT, Washington, D.C. 20546. 
Radiant Heating Concept Efficient for Light-Transmitting Windows 
Window Cover
	
	
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hield 
Centerline of 
of lncidence 
s AngleParabolic Reflector 
Glass Angle of View 
 
Heater Rod 
Figure 1. Transverse Section of Heated Window 
Highly efficient windows have been designed which 
are single-pane, uncoated, and particularly suitable 
for the most accurate photography. These windows 
could be used in special telescopes and cameras for 
oceanographic and related studies. 
Windows induce condensation when they become 
cold. Multipane windows reduce transmission of 
light, increase unwanted reflections, and permit for-
mation of deposits on the enclosed surfaces—products 
of outgassing from sealing compounds. Coating of 
panes filters light significantly. 
A single-pane window has two opposed rod heaters, 
with reflectors, mounted outside and beside it (Figs. I 
and 2). Electrically powered to a temperature of about 
500°F the rods direct at the pane infrared rays of long 
wavelength. About 35% of the energy consumed by 
the rods reaches the panes; about 25% of this is radi-
ated directly by the rods, while about 75% is reflected 
by the reflectors. Windows can be heated to fairly
even temperatures for prevention of condensation; 
a maximum temperature difference of about 16°F is 
predicted for one design of a spacecraft's window. 
Tests of a simulated window in a partial-vacuum 
chamber have confirmed these predictions and the 
ability of glass to absorb infrared energy at low angles 
of incidence. The window is highly absorptive of 
infrared rays while its transmission of shorter-wave-
length visible and near-visible portions of the spec-
trum is very efficient; thus it acts like a black plate 
toward infrared energy and like an open area for the 
useful wavelengths. 
Note: 
Requests for further information may be directed 
to:
Technology Utilization Officer 
Marshall Space Flight Center 
Huntsville, Alabama 35812 
Reference: TSP70- 10324
(continued overleaf) 
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https://ntrs.nasa.gov/search.jsp?R=19700000312 2020-03-17T00:20:34+00:00Z
S.	 '4 
Reflector
Heater Rod 
Pane 
Patent status: 
No patent action is contemplated by NASA. 
Source: R. J. Novoryta and J. R. Neuman of 
Martin Marietta Corporation 
under contract to 
Marshall Space Flight Center 
(M FS-20630)
Figure 2. View of Half Window; Schematic 
Brief 70-10324	 Category 03


Radiant heating concept efficient for light-transmitting windows

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